MEMOIRS OF THE LIFE OF DAVID RITTENHOUSE; ANTERIOR TO HIS SETTLEMENT IN PHILADELPHIA.

The paternal ancestors of David Rittenhouse were early and long seated at Arnheim, a fortified city on the Rhine, and capital of the district of Velewe or Veluive, sometimes called the Velau, in the Batavian province of Guelderland;^[55] where, it is said, they 80conducted manufactories of paper,^[56] during the course of some generations. The orthography of the name 81was formerly Rittinghuysen, as the writer of these memoirs was informed by an European member of this family.^[57] 82But it is net improbable, that, in more strict conformity to the idiom of its Saxo-Germanic original, the name was spelt Ritterhuysen^[58]—or, perhaps, Ritterhausen; which signifies, in our language, Knights’ Houses: a conjecture that seems to be somewhat corroborated by the chivalrous emblems alluding to this name, belonging to the family, and which have been already noticed.

It has been asserted, that the first of the Rittenhouses who migrated to America, was named William; and that he went from Guelderland to the (now) state of New-York, while it was yet a Dutch colony. This William was also said to have left at Arnheim a brother, Nicholas, who continued to carry on the paper-making business in that city.^[59] But, in a genealogical 83account of the family in the possession of the Memorialist, Garrett (or Gerard) and Nicholas 84Rittenhouse are stated to have arrived at New-York, from Holland, so late as the year 1690: it likewise states, that Nicholas there married Wilhelmina Dewees, a sister of William Dewees, who came thither about the same time; and that, soon afterwards, they all removed to the neighbourhood of Germantown in Pennsylvania; where Nicholas established the first 85paper-mill ever erected in America.^[60] It is believed, however, that Garrett and Nicholas Rittenhouse were sons of William; who is supposed to have arrived in some part of the original territories of New-York, prior to the year 1674;^[61] that the Nicholas left in Arnheim, was his brother; and that his sons Garrett and Nicholas, who are stated to have been the first of the family that settled in New-York, in 1690 (from whence they removed, “soon afterwards,” into Pennsylvania,) did, in fact, transfer themselves into this latter province, in that year.—Garrett left children; some of whose descendants are resident in Pennsylvania, and others in New-Jersey.

Nicholas Rittenhouse, the grandfather of our Philosopher, died about the year 1730; leaving three 86sons, William, Henry, and Matthias; and four daughters, Psyche, Mary, Catharine, and Susanna. Of these daughters, Psyche intermarried with John Gorgas, from whom are descended the Gorgas’s of Cresham and Cocolico; Mary, with John Johnson, the father of Casper, John, Nicholas, William, and Benjamin Johnson, some of whom are now (or were lately) living, in the neighbourhood of Germantown; Catharine, with Jacob Engle, in the same vicinity; and Susanna, with Henry Heiley of Goshehoppen.

William Rittenhouse, the eldest brother of our Philosopher’s father, died at the paper-mills, near Germantown. He left several children, one of whom did lately, and perhaps yet does, carry on those works.—Henry and Matthias removed to the townships of Worcester and Norriton, about the year 1732 or 1733; where both lived to be upwards of seventy years of age.

The old American stock of the Rittenhouses were Anabaptists,^[62] and persons of very considerable note 87in that religious society. Probably, therefore, they were induced to establish their residence in Pennsylvania, towards the close of the seventeenth century, by the tolerating principles held forth by William Penn,^[63] 88in respect to religious^[64] concerns; the justness of the tenure by which he became proprietor of the 89soil;^[65] and the excellence of the political regulations established by that great legislator, for the civil government of his newly-acquired domains.

90Matthias, the youngest son of Nicholas Rittenhouse, by Wilhelmina Dewees his wife, was born at 91the paper-mills belonging to his family, near Germantown,^[66] in the county of Philadelphia and about eight miles from the capital of Pennsylvania, in the year 1703. Having abandoned the occupation of a paper-maker, when about twenty-nine years of age, and two years after his father’s death, he then commenced the business of a farmer, on a piece of land he had purchased in the township of Norriton,^[67] about twenty 92miles from the city of Philadelphia; his brother Henry establishing himself in the same manner, in the adjoining township of Worcester. In October, 1727,—about three years prior to Matthias’s removal from the vicinity of Germantown,—he had become a married man. His wife was Elizabeth William (or Williams) who was born in 1704, and was daughter of Evan William, a native of Wales. Her father, a farmer, dying while she was a child, she was placed under the charge of an elderly English (or, more probably, Welsh) gentleman, in the neighbourhood, of the name of Richard Jones; a relation of her family. That truly respectable woman possessed a cheerful temper, with a mind uncommonly vigorous and comprehensive: but her education was much neglected, as is too often the fate of orphan children. Yet, perhaps, no censure ought justly to be imputable to Mr. Jones, in this case; because there were very few schools of any kind, in country situations, at that early day.^[68]

93The extraordinary natural understanding of this person, so very nearly related as she was to the subject of these memoirs, seemed to the writer to merit particular notice; and the more especially, for a reason which shall be hereafter mentioned.

By this wife, Matthias Rittenhouse had four sons and six daughters;^[69] three of whom died in their minority. 94The three eldest of the children were born at the place of their father’s nativity; the others, at Norriton. Of the former number was David, the eldest son, the subject of these memoirs.—He was born on the 8th day of April, 1732.^[70]

95This son was an infant, when his family removed to Norriton and engaged in the business of farming; and his father appears, early, to have designed him for this most useful and very respectable employment. Accordingly, as soon as the boy arrived at a sufficient age to assist in conducting the affairs of the farm, he was occupied as an husbandman. This kind of occupation seems to have commenced at a very early period of his life; for it is ascertained, that, about the fourteenth year of his age, he was actually employed in ploughing his father’s fields.^[71]

96At that period of our future Philosopher’s life, early as it was, his uncultivated mind, naturally teeming with the most prolific germs of yet unexpanded science, began to unfold those buds of genius, which soon after attained that wonderful luxuriance of growth by which the usefulness and splendour of his talents became eminently conspicuous. His brother Benjamin relates,^[72] that, while David was thus employed at the plough, from the age of fourteen years and for some time after, he (this informant,) then a young boy, was frequently sent to call him to his 97meals; at which times he repeatedly observed, that not only the fences at the head of many of the furrows, but even his plough and its handles, were covered over with chalked numerical figures, &c.^[73]—Hence it is evident, that the exuberance of a sublime native genius and of almost unbounded intellectual powers, unaided by any artificial means of excitement, were enabled, by dint of their own energy, to burst through those restraints which the corporeal employments of his youth necessarily imposed upon them.

During that portion of his life in which this youthful philosopher pursued the ordinary occupations of a husbandman, which continued until about the eighteenth year of his age, as well as in his earlier youth, he appeared to have inherited from healthful parents a sound constitution, and to have enjoyed good health.

It was at this period, or rather about the seventeenth year of his age, that he made a wooden clock, of very ingenious workmanship: and soon after, he constructed one of the same materials that compose the common four-and-twenty hour clock, and upon the same principles. But he had exhibited much earlier proofs of his mechanical genius, by making, when 98only seven or eight years old, a complete water-mill in miniature.

Mr. Rittenhouse’s father was a very respectable man: he possessed a good understanding, united to a most benevolent heart and great simplicity of manners. The writer long knew him; and, from his early acquaintance with the character, the appearance, and the habits of this worthy sire of an illustrious son, he had long supposed him to have been inclined to the religious principles of the society called Friends, although he had been bred a Baptist:—but a circumstance which shall be noticed hereafter, will evince the liberality of this good man’s opinions, in the all-important concern of religion. Yet, with truly estimable qualities, both of the head and heart, old Mr. Rittenhouse had no claims to what is termed genius; and therefore did not, probably, duly appreciate the early specimens of that talent, which appeared so conspicuous in his son David. Hence, he was for some time opposed to the young man’s earnest desire to renounce agricultural employments; for the purpose of devoting himself, altogether, to philosophical pursuits, in connexion with some such mechanical profession as might best comport with useful objects of natural philosophy, and be most likely, at the same time, to afford him the means of a comfortable subsistence. At length, however, the father yielded his own inclinations, in order to gratify what was manifestly the irresistible impulse of his son’s genius: he supplied him 99with money to purchase, in Philadelphia, such tools as were more immediately necessary for commencing the clock-making business, which the son then adopted as his profession.

About the same time, young Mr. Rittenhouse erected on the side of a public road, and on his father’s land in the township of Norriton, a small but commodious work-shop; and, after having made many implements of the trade with his own hands, to supply the deficiency of many such as were wanting in his purchased stock, he set out in good earnest as a clock and mathematical instrument maker.

From the age of eighteen or nineteen to twenty-five, Mr. Rittenhouse applied himself unremittingly, both to his trade and his studies. Employed throughout the day in his attention to the former, he devoted much of his nights to the latter. Indeed he deprived himself of the necessary hours of rest; for it was his almost invariable practice to sit up, at his books, until midnight, sometimes much later.

It was in this interval and by these means, that our young philosopher impaired his constitution, and contracted a pain in his breast; or rather, as he himself described that malady to the writer, “a constant heat in the pit of the stomach, affecting a space not exceeding the size of half a guinea, attended at times with much pain;” a sensation from which he was 100never exempt, during the remainder of his life. About this time, he retired from all business, and passed several weeks at the Yellow Springs, distant but a few miles from his place of residence. He there bathed and drank the waters; and from the use of this chalybeate, he appeared to have derived some benefit to his general health, though it afforded little alleviation of the pain in his breast.

A due regard to the sacredness of historic truth demands, that some circumstances which occurred while Mr. Rittenhouse was yet a youth, and one which it is believed had a very considerable influence on his subsequent pursuits and reputation, should now be made known. Because the writer of these memoirs conceives he ought not to be restrained, by motives which would appear to him to arise from a mistaken delicacy, from introducing into his work such notices of his own father, long since deceased, as do justice to his memory; while they also serve to elucidate the biographical history of Mr. Rittenhouse.

In the year 1751, when David Rittenhouse was about nineteen years of age, Thomas Barton, who was two years elder than David, opened a school in the neighbourhood of Mr. Matthias Rittenhouse. It was while Mr. Barton continued in that place, supposed to have been about a year and a half, that he became acquainted with the Rittenhouse Family; an acquaintance which soon ripened into a warm friendship 101for young Mr. Rittenhouse, and a more tender attachment to his sister, Esther.

Two years afterwards (in 1753), the personal attractions and fine understanding of the sister rendered her the wife of Mr. Barton; who, for some time before, had officiated as one of the tutors in the then recently-established Academy, afterwards College, of Philadelphia; now the University of Pennsylvania. In this station, he continued until the autumn of 1754; when he embarked for England, for the purpose of receiving episcopal ordination in the church, and returned to Pennsylvania in the early part of the following year.

The very intimate connexion thus formed between Mr. Barton and a sister of Mr. Rittenhouse (who was two years elder than this brother), strengthened the bands of friendship which had so early united these young men: a friendship affectionate and sincere, and one which never ceased until Mr. Barton’s death, nearly thirty years afterwards; notwithstanding some difference of political opinions had arisen between these brothers-in-law, in the latter part of that period, in consequence of the declaration of the American independence.

Mr. Barton was a native of Ireland, descended from an English family; of which, either two or three brothers settled in that kingdom, during the disastrous times in 102the interregnum of Charles I. Having obtained very considerable grants of land in Ireland, this family possessed ample estates in their then adopted country. Hence, flattering prospects of an establishment there, in respect to fortune, were held out to their descendants. Through one of those untoward circumstances, however, by means of which the most unexpected revolutions in the affairs of families and individuals have been sometimes produced, the expectations of an independent patrimony which our Mr. Barton’s father had entertained, were speedily dissipated. Nevertheless, this gentleman, who was the eldest son of his family, was instructed in the rudiments of a classical education in the vicinity of his family residence in the county of Monaghan, under the direction of the Rev. Mr. Folds, a respectable English clergyman; and at a suitable age, he was sent to the university of Dublin, where he finished his academical education. Entirely destitute of fortune, but possessing a strong intellect, stored with useful and ornamental learning as well as an ardent and enterprizing spirit, this young adventurer arrived in Philadelphia soon after he had completed his scholastic studies.

The writer’s principal design, in presenting to the public view these slight sketches of the early history of the late Rev. Mr. Barton, shall be now explained.

When Mr. Rittenhouse’s father established his residence at Norriton, and during the minority of the 103son, there were no schools in the vicinity at which any thing more was taught, than reading and writing in the English language and the simplest rules of arithmetic. Young Mr. Rittenhouse’s school-education, in his early youth, was therefore necessarily bounded by these scanty limits of accessible instruction: He was, in truth, taught nothing beyond these very circumscribed bounds of literary knowledge, prior to the nineteenth year of his age; though it is certain, that some years before that period of his life, he began to be known—at least in his own neighbourhood—as a mathematician and astronomer, in consequence of his cultivation of the transcendent genius with which heaven had endued him.

Under such circumstances as these, the familiar intercourse between David Rittenhouse and his young friend Barton, which commenced when the age of the former did not exceed nineteen years, could not fail to prove highly advantageous to the mental improvement of both. The one possessed a sublime native genius; which, however, was yet but very imperfectly cultivated, for want of the indispensable means of extending the bounds of natural knowledge: the other had enjoyed the use of those means, in an eminent degree, and thus justly acquired the reputation of a man of learning. A reciprocation of these different advantages, as may be well supposed, greatly promoted the intellectual improvement of both.

104It will be readily conceived, that Mr. Barton’s knowledge of books must have rendered even his conversation instructive to Mr. Rittenhouse, at so early a period of his life. But the former so greatly admired the natural powers of his young friend’s mind, that he took a delight in obtaining for him access to such philosophical works, and other useful books, as he was then enabled to procure for his use; besides directing, as far as he was capable, the course of his studies.

After Mr. Barton’s removal to Philadelphia and while he resided in that city, his means of furnishing his friend with books, suitable for his instruction, were greatly enlarged; an advantage of which he most assiduously availed himself: and it is supposed to have been about this time, that a small circulating library was established in Norriton, at the instance of Mr. Barton, zealously seconded by the co-operation and influence of Mr. Rittenhouse.

Finally, when Mr. Barton returned from England, in the year 1755—at which time Mr. Rittenhouse was yet but twenty-three years of age, he brought with him a valuable addition to his friend’sfriend’s little library; consisting, in part, of books which he himself had commissioned Mr. Barton to purchase for him.^[74]

105No doubt can be entertained, that Mr. Rittenhouse derived the great and extraordinary faculties of his mind from nature; and it is equally evident, that for some years after he arrived to manhood, he possessed very slender means of improving his natural talents: Nay further, it is well known to those who were long personally acquaintedacquainted with him, that after his removal to Philadelphia, when he was eight-and-thirty years of age, a period of life at which the place of his residence, and the condition of his pecuniary affairs, united in placing within his reach much that is dear to science,—even then, his long continued professional employment and the various public stations he filled, in addition to frequent ill health, deprived him of a large share of those advantages. The vast stock of knowledge which, under such untoward circumstances, he actually acquired, is therefore an additional proof of his native strength of intellect.

But, wonderful as a kind of intuitive knowledge he possessed really was, his mental powers would probably have remained hidden from the world, they 106would have been very imperfectly cultivated, at best, had not an incident apparently trivial, and which occurred when our Astronomer was a young boy, furnished what was, in all probability, the very first incitement to an active employment of his philosophical as well as mechanical genius.

Mr. Rittenhouse’s mother having been already noticed somewhat particularly, the reason for this being done shall be here stated: it is connected with the incident just now referred to. This valuable woman had two brothers, David and Lewis Williams (or William), both of whom died in their minority. David, the elder of these, pursued the trade of a carpenter, or joiner. Though, like his nephew and namesake, he was almost wholly an uneducated youth, he also, like him, early discovered an unusual genius and strength of mind. After the death of this young man, on opening a chest containing the implements of his trade which was deposited at Mr. M. Rittenhouse’s, (in whose family it is presumed he dwelt,) a few elementary books, treating of arithmetic and geometry, were found in it: With these, there were also various calculations and other papers, in manuscript; all, the productions of David Williams himself, and such as indicated not only an uncommon genius, but an active spirit of philosophical research. To this humble yet valuable coffer of his deceased uncle, Mr. Rittenhouse had free access, while yet a very young boy. He often spoke of this acquisition as a treasure; 107inasmuchinasmuch as the instruments of his uncle’s calling afforded him some means of exercising the bent of his genius towards mechanism, while the books and manuscripts early led his mind to those congenial pursuits in mathematical and astronomical science, which Were ever after the favourite objects of his studies.^[75]

108It being thus apparent, that not only Mr. Rittenhouse’s mother but her brother David Williams were persons of uncommon intellectual powers, the writer thinks it fairly presumable, that our Astronomer 109inherited his genius from his mother’s family.^[76] His surviving brother has decidedly expressed this 110opinion: in a letter on the subject of the deceased, addressed to the writer of these memoirs soon after 111Dr. Rittenhouse’s death, he says—“I am convinced his genius was more derived from his mother, than from his father.”

A casualty that occurred in the year 1756, appeared to have been very near depriving the world of the talents, services, and example of our Philosopher, at a very early period of those pursuits in which he was afterwards so eagerly engaged. This circumstance is thus narrated by himself, in a letter dated the 26th of July, in that year, and addressed to the Rev. Mr. Barton, at his then residence in Redding township, York county.^[77]

112“I was,” said our young philosopher, “obliged to ride hard to reach Lancaster, the evening after I left you; and being somewhat tired myself, as well as my horse, I determined to go to the Dunker’s-Town,^[78] where I staid the remainder of that day and the night following. I was there entertained with an epitome of all the whimsies mankind are capable of conceiving. 113Yet it seemed to me the most melancholy place in the world, and I believe would soon kill me were I to continue there; though the people were exceedingly civil and kind, and the situation of the place is pleasant enough.^[79] From thence I went homewards, 114through Reading;^[80] where I was agreeably surprised, the number and goodness of the buildings far exceeding my expectations.

115“You have perhaps seen, in one of the last papers, an account of the prodigiously large hail-stones which fell in Plymouth.^[81] The lightning struck a tall green poplar standing in our meadow, just before the door, and levelled it with the earth. I was standing between the tree and house; and, at the same instant that I saw the flash of lightning, felt a most violent shock through my whole body,—and was stunned with such a horrible noise, that it is impossible for imagination to represent any thing like it.”

The advantages and the disadvantages, which Mr. Rittenhouse respectively enjoyed and encountered, until after he had attained to the period of manhood, have been mentioned; and it will be readily perceived, that the latter greatly outweighed the former, in every other particular than that of his native genius, which alone was sufficient to preponderate against innumerable difficulties.

The great deficiencies in his education, as well as their causes, having been misconceived and incorrectly represented in some publications, a due regard to truth demands a correction of such mistaken opinions. 116Soon after his death, there appeared in the Maryland Journal, “Anecdotical Notices of Mr. David Rittenhouse;” which, although written with some ingenuity and knowledge of the subject, contained several errors. It is therein asserted, among other things, that “his parents, incapable of giving him any other education than common reading and writing, intended to have brought him up to country-business; but, being blessed by nature with a mechanical turn of mind, he soon gave specimens of his ingenuity in making wooden clocks: This so recommended him to notice, as to give him an opportunity of learning the clock-making business.”—It has been already shewn, that Mr. Rittenhouse never received the least instruction in any mechanic art; and it is not ascertained that he ever made more than one wooden clock. It is also notoriously an error, that his parents were “incapable” of giving him any other education, than the common schooling he received: they were by no means poor, though not wealthy. His father inherited some patrimony; and he had, besides, been about nine years concerned in conducting the paper-manufactory near Germantown, after his one-and-twentieth year, before he purchased the Norriton farm.^[82] This part of his estate he was enabled to give to his eldest son, David, about the year 1764; prior to which time the old gentleman removed to a farm he had purchased, nearly 117adjoining it in Worcester township, and on which he had erected a good two-story stone dwelling-house with suitable out-houses. There Mr. David Rittenhouse’s father and mother afterwards resided, together with their other son, Benjamin, (the house being so constructed as, conveniently, to accommodate two small families,) until the death of old Mrs. Rittenhouse in the autumn of 1777, at the age of seventy-three years, and of her husband in the autumn of 1780, in the seventy-eighth year of his age. The Worcester farm was left to the younger son: and, in addition to these not inconsiderable establishments for his sons, the old gentleman had given small portions to each of his five daughters, when they severally married. The remains of this worthy and upright man, for he truly merited that character, were interred in the cemetery belonging to a Baptist congregation, in the neighbourhood, in which both he and his wife had long attended divine worship. But, some years before his death, the old gentleman disposed of a lot of ground very near to his own house,—and gratuitously, if the writer’s information be correct,—to a Presbyterian congregation, for a burial place, and site for a church they were then about to erect. If this little piece of land was a donation to the religious society to whom it belongs, the grant of it, though not of great value, furnishes an instance of that liberality of sentiment and goodness of heart which characterized our Astronomer’s father, and to which some allusion is before made.

118When, therefore, all the circumstances here mentioned, respecting Matthias Rittenhouse’s property and condition of life, shall be taken into view, it will be evident that he possessed a decent competency; with an estate quite independent, though not large: for he never enjoyed what is now termed affluence.

Concerning our Astronomer’s early life and condition, even his eloquent eulogist, Dr. Rush, was mistaken in some particulars. His assertion, that Mr. Rittenhouse was descended from parents “distinguished for probity, industry, and simple manners,” is perfectly correct. But, although he was comparatively “humble” in his “origin,” his father held the highly respectable station of an intelligent, independent farmer;^[83] and it has been also seen, that his paternal ancestors, for some generations in succession, were proprietors of considerable manufactories of an article important in commerce and the arts, and eminently useful in literature and science as well as in the common affairs of life.

Dr. Rush has remarked, in regard to Mr. Rittenhouse’s talents first becoming generally known, that “the discovery of his uncommon merit belonged chiefly to his brother-in-law, the Rev. Mr. Barton, Dr. Smith, and the late Mr. John Lukens.” Perhaps it 119might be said, with greater strictness, that the “discovery” here spoken of, belonged solely to Mr. Barton; by whom it was communicated, very early, to his learned and reverend friend, Dr. Smith,—and through him, to the ingenious astronomical observer, Mr. Lukens, (afterwards surveyer-general,) as well as some other distinguished characters of that time. The writer in the Maryland paper before referred to, after having noticed the prevailing opinion that Mr. Rittenhouse was self-taught, had corrected the full extent of that misconception, in these words: “This is not strictly true; for, while engaged in these acquirements,” (astronomy, &c.) “the Rev. Mr. Barton, a learned episcopal clergyman of Lancaster, married his sister.”——“Mr. Barton, admiring the simplicity of manners and natural genius of his brother-in-law, afforded him every assistance in his power,—not only in mathematics, but in several other branches of literature: Mr. Rittenhouse was worthy of his notice; for he lost no time, and spared no pains, to improve himself in knowledge, as far as his limited education would permit.”

Hence, as well as from the preceding narrative, it will appear that Dr. Rush was led into a further mistake, respecting Mr. Rittenhouse.—In regard to his exalted genius, the learned professor has amply done justice to his memory. He has, in particular, recorded one extraordinary fact, in proof of his genius, well worthy of notice; and which is therefore related in 120the Professor’s own words.——“It was during the residence of our ingenious philosopher with his father, in the country, that he made himself master of Sir Isaac Newton’s Principia, which he read in the English translation of Mr. Motte. It was here, likewise, he became acquainted with the science of Fluxions; of which sublime invention he believed himself, for a while, to be the author: nor did he know for some years afterwards, that a contest had been carried on between Sir Isaac Newton and Leibnitz, for the honour of that great and useful discovery.” Then exclaims the ingenious eulogist, in terms of well-founded admiration, “What a mind was here!”—But, immediately after, he adds—“Without literary friends or society, and with but two or three books, he became, before he had reached his four-and-twentieth year, the rival of two of the greatest mathematicians in Europe!”—The circumstance must, then, have escaped Dr. Rush’s recollection—if indeed he had ever been made acquainted with it,—that five years before Mr. Rittenhouse attained to the age of twenty-four, he found at least one literary friend, in Mr. Barton; whose intimate society he long enjoyed, prior to that period; and that, through his means, he had access to many books.^[84]

121It is not meant to be insinuated, however, that Mr. Barton ever gave Mr. Rittenhouse any insight into the knowledge of fluxions; or, indeed, much instruction, if any at all, in other of the higher branches of 122mathematics: because the first named gentleman never did himself pretend to the character of a profound mathematician; and because, likewise, although always esteemed a man of learning, his pursuits in science and literature were chiefly directed to objects of a different nature. That Mr. Rittenhouse derived some instruction and information from his early acquaintance with Mr. Barton, is certain: but, whatever may have been the extent of the literary advantages which the latter was enabled to confer on his young friend and companion, they could not in any degree derogate from the intrinsic excellence and greatness of our Astronomer’s innate geniusgenius.

That a mind so formed as that of our young philosopher—situated in life as he was—should have impelled him to assume the business of clock-making, can not be a matter of surprize: this occupation, connected with that of a mathematical instrument maker, is such as may be well supposed to have presented itself to his youthful ingenuity; being in accordance with the philosophical bent of his genius in his early years, while yet untutored in science and unknown to the world.

The great utility of the common clock, in measuring time, is universally known. It possesses numerous and manifest advantages, beyond those of sun-dials, clepsydræ, sand-glasses, and other horological instruments, by reason of its vastly superior accuracy: the 123sun-dial, indeed, is oftentimes wholly useless in all situations, even in the day-time; and always necessarily so, at night.

But the many improvements which have been made in modern times, in chronometers,—more especially in pendulum-clocks,—have very much advanced a correspondent accuracy in astronomical observations: and these improvements, together with those lately made in telescopes—chiefly by Dr. Herschel, the discoverer of the Georgium Sidus^[85]—afford good 124grounds for hoping, that yet farther and more important additions will continue to be made to the recent discoveries in astronomy.

125Further improvements may also be expected to take place, in the construction of watches and other spring-chronometers; 126so as to render them still more useful for the purposes of navigation, by ascertaining with greater precision the longitude at sea.^[86] For this 127purpose, the finely-improved English time-keepers of Harrison, Mudge, and others, have been found of the greatest utility. Mr. de Zach, (in his Explanation and uses of the Tables of the Motions of the Sun,^[87]) after some observations on determining 128differences of longitude by means of astronomical observation, says,^[88]—“De cæteris longitudinem determinandi 129modis, non est hic disserendi locus;—de uno vero, horologiâ maritimâ seu nauticâ, quidquam adjicere non alienum erit. Triginta jam abhinc annis, ingeniosissimi horologiorum artifices, Harrison, Cummings, Kendal, Arnold, Mudge, apud Anglos,—Le Roy et Berthoud apud Gallos, varia navigantium usui, egregia excogitaverant, et ad magnum perduxerant perfectionis gradum, horologia nautica, (Anglis, Time-keeper.) Cum eorum in longitudinibus itenere maritimo definiendis, usum quisque norit, plura hic dicere abstineo; simile horologium ab ingenioso horolopega Thom. Mudge constructum, in Observatorio Regio Grenovicensi sæpius exploratum, anno 1784, a Clar. 130D. Campbell, classis navalis præfecto^[89] ad Terram Novam (Newfoundland) vectum, et reductum, ab hoc tempore in Observatorio Excellentissimi Comitis de Bruhl, Londini, Doverstreet, assidue observatum est. Hoc ipsum horologium maritimum, anno 1786, in terrestribus, iteneris longitudines determinandi gratia, concreditum mihi fuit, cum â Serenissimo Duce Saxe-Gothanâ, omnium scientiarum bonarumque artium patrono, imprimis astronomiæ, faventissimo, Londino evocatus in Germaniam me conferrem, ubi amplissimæ splendidissimæ Speculæ, Astronomicæ Gothanæ extruendæ cura mihi demandata erat;^[90] attuli eodem 131hoc tempore, ad Serenissimi mandatum, minoris molis horologium, quod in braccis gestari solet (Anglis, 132Pocket-chronometer,) a Londiniensi artifice, D. Josiah Emery,^[91] constructum, quod summâ accuratione et 133subtilitate elaboratum, nil majoribus cedit horologiis nauticis, ut videre licet ex tribus horum motuum elenchis ab Ilustr. Comite de Bruhl, et â aliorum Dr. Arnold, nuperrime publici juris factis. Sub finem anni 1786 et ad initium 1787, Serenissimum in itenere per Germaniam, Galliam, et Italiam, comitatus sum: hoc itenere quorundam locorum et Specularum astronomicarum longitudines definitæ sunt ex comparatione temporis horologii maritimi (quod ad tempus solare medium Londinense, in Doverstreet incedebat) cum tempore medio loci, quod sextante Hadleianâ per solis altitudines, quas correspondentes dicimus, vel ex comparatione cum illo, quod in Speculis Astronomicis ab ipsis astronomis traditum nobis fuit. Iisdem itaque automatis, cum primum Gotham advenissem, observatorii futuri longitudinem maximâ cum curâ atque diligentiâ definivi, quam paucis post diebus Serenissimus Dux Londinum profectus, chronometro suo secum deportato denuo perbelle comprobaverat.”

This very respectable testimony of an eminent German astronomer affords incontestable proof of the great accuracy, of which nautical chronometers are susceptible, and to which they have actually been brought by some artists of celebrity, mostly English.^[92]

134The general use of the common clock ought not to derogate from the ingenuity of an invention of such universal importance in the affairs of human life. The pendulum-clock now in use was brought to some degree of perfection, if not invented, by Huygens,^[93] who was one of the first mathematicians and 135astronomers of the age in which he lived: and the date of this invention is about the middle of the seventeenth century; although GalileoGalileo disputed with him the discovery, a few years earlier. Clocks of some kind date their antiquity much higher; some writers pretending to carry their invention back as far as the year 510 of the Christian era. However, on the authority of Conrad Gesner,^[94] the honour of inventing the clock, before the application of the pendulum to these machines was made by Huygens, belongs to England: He says, that “Richard Wallingford, an English abbot of St. Albans, who flourished in the year 1326, made a wonderful clock by a most excellent art; the like of which could not 136be produced in all Europe.”^[95] This was forty-six years before Henry de Vic, a German, made his clock for Charles V. king of France; and fifty-six years before the duke of Burgundy ordered one, which sounded the hour, to be carried away from the city of Courtray, in Flanders.

Within our own day and a short period of time preceding it, great improvements have been made in the construction of the pendulum-clock,^[96] as well as 137in other descriptions of Chronometers.^[97] Mr. Rittenhouse’s early zeal in his practical researches into 138astronomy, prompted him to desire the greatest possible accuracy in the construction of time-pieces adapted to astronomical purposes; and uniting, as he did, operative skill with a thorough knowledge of the principles upon which their construction depends, he was enabled—impelled by so powerful a motive—to display to the world, by his own manual ingenuity, the near approach to perfection to which the pendulum-chronometer may be brought. Besides his astronomical pursuits, his early employment in ascertaining the limits and fixing the territorial boundaries of Pennsylvania, and of some of the neighbouring states, obliged him to supply himself with chronometers of the greatest possible accuracy: and these were either made by his own hands, or under his immediate inspection by his brother, who, with the aid of his instruction, became an excellent mechanician. One of these fine instruments, bearing on its face the name of Benjamin Rittenhouse as the maker, and the date of the year 1786, is now in the possession of Mr. Norton 139Prior,^[98] of Philadelphia: but that admirable one, the workmanship of which was executed by our Philosopher 140himself, and which was part of the apparatus of his Philadelphia Observatory, is now placed in the hall of the American Philosophical Society.^[99] This is constructed on a greatly improved plan of his own, which improvement was afterwards applied to that now belonging to Mr. Prior; and the latter is the same chronometer, it is believed, that was used by Mr. D. Rittenhouse, in fixing the northern line which divides Pennsylvania from New York, and in establishing the boundary line between the last mentioned state, and Pennsylvania and Massachusetts, respectively, in the years 1786 and 1787.—A descriptiondescription of 141the principles of his observatory-chronometer here mentioned, together with some account of its mechanism, will be found in the Appendix: the former having been communicated to the writer of these memoirs by the ingenious Robert Patterson, Esq. director of the Mint; and the latter by that able mechanician, Mr. Henry Voight, chief coiner in that institution,—a person who, by reason of his well-known skill as a clock and watch-maker, was employed by Mr. Rittenhouse more than forty years since, in the fabrication of some of his philosophical instruments.

The great accuracy and exquisite workmanship displayed in every thing belonging to the profession he pursued, that came through his hands, soon became pretty extensively known: and this knowledge of his mechanical abilities, assisted by the reputation he had already acquired as a mathematician and astronomer, in a short time procured him the friendship, respect and patronage, of some eminent scientific characters; while it promoted his interest, in the profession he had thus newly chosen. In this he was, nevertheless, self-taught; for he never received the least instruction from any person, in any mechanic art whatever: and, therefore, if he were to be considered as being merely an excellent artist, in an occupation intimately connected with the science of mathematics—untutored, as he was, in any art or science,—he would deservedly be deemed an extraordinary and eminent man. It will be perceived, however, 142that it was the union of the almost unbounded powers of his genius, and his prodigious acquirements in a sublime science, with his wonderful abilities as a philosophical mechanic—and these faculties and attainments, moreover, combined with an amiable and virtuous character,—which constituted that celebrity so justly attached to his name.

Our young philosopher lived a retired, though by no means an inactive life, in his father’s family, for several years after he arrived to (what is usually termed) lawful age. In this situation, which was a pleasant one in many respects, he long continued to enjoy the tranquil scenes of rural life, amidst the society of an amiable and very intelligent family-circle, and surrounded by many worthy and estimable neighbours, by whom he was both loved and respected. His chief occupation was the profession he had chosen; but in such occasional intervals of personal abstraction from the mechanical part of his business, as the assistance the workmen he employed enabled him to obtain, he devoted much of the time to philosophical pursuits and study. Frugal in his expenditures, his industry furnished him amply with the means of comfort; and in the plentiful and decent mansion of his father’s family he experienced, with contentment, almost every gratification that a reasonable mind could desire. Good health seemed alone to be wanting to complete his happiness, in his earlier years; 143a privation which he felt through the greater part of his life.

Such was the condition of Mr. Rittenhouse, while he remained under the same roof with his father and mother, and some of their unmarried children. It was a mode of life which his disposition was calculated to enjoy; for, strongly attached to his kindred and friends by the benevolence of his nature, he derived much of his happiness from the reciprocal affections of a domestic circle and the kind intercourses of friendly esteem.

There does not appear to have been, for a long time, any occurrence that could have much disturbed the placid composure of our philosopher’s mind,—until 1762; in which year his sister Anne died, in the twenty-sixth year of her age. She was the wife of Mr. George Shoemaker, a respectable citizen of Philadelphia, and a member of the religious society of Friends. A letter which Mr. Rittenhouse wrote to his brother-in-law Mr. Barton, in October 1762, announcing this event, indicates the keenness of his sensibility on the occasion. Mrs. Shoemaker was a woman of intrinsic worth; she died in the prime of life; and it is believed, she was the first of Mr. Rittenhouse’s affectionate little band of brothers and sisters who had attained to the age of maturity, that he had then lost. After giving a circumstantial account of his sister’s illness and death, he informs Mr. 144Barton, that Mr. Daniel Stanton, an eminent public speaker in the society of Friends,^[100] attended her in her last illness, at her particular request;—and, added Mr. Rittenhouse, “the same worthy gentleman who visited her in her sickness, delivered an excellent exhortation at the grave,—giving, in a few words, a very just character, I think, of our deceased sister.”

Mr. Shoemaker (who married again) had an only child named Jacob, by his first wife here mentioned. This son became a young man of promising character: but, having entered the American army at the commencement of the revolutionary war, and attained (it is believed) the rank of captain, under the patronage of his uncle David Rittenhouse, he was slain in the campaign of 1781, in South-Carolina. Mr. Rittenhouse was much afflicted by the death of this gallant young man, who fell in the flower of his age.

An occasion presented itself, in which Mr. Rittenhouse, when only in the thirty-second year of his age, was employed in transacting an important piece of business of a public nature: it was as follows.

145In consequence of a petition of the Messrs. Penn to the court of chancery in England, exhibited in the year 1735, it was decreed by the lord chancellor, in 1750,—That an agreement which had been entered into between the Penns and Lord Baltimore, concerning the long-subsisting controversy relative to the boundary lines between Pennsylvania and Maryland, should be carried into specific execution: and, accordingly, a final agreement was executed by those proprietaries of the two provinces, on the fourth day Julyday July, 1760.

In pursuance of the chancellor’s decree, provision was made for ascertaining and fixing the “circle,” to be “drawn at twelve miles distance from New-Castle, northward and westward, unto the beginning of the fortieth degree of north latitude;”—and thence, running a straight line westward, five degrees in longitude, to be computed from the eastern boundary; as described in the royal charter to William Penn. Commissioners were appointed under the chancery-degree, for settling these boundaries. But nothing was definitively done in the business, until the eleventh of January, 1769; when the line which was run by Messrs. Mason and Dixon in the years 1767 and 1768, in pursuance of the final agreement between the parties before mentioned, was approved and ratified by the king in council.

146So early, however, as about the close of the year 1763, four or five years before the running and marking of Mason and Dixon’s line, Mr. Rittenhouse was employed by the Penn family in making some geographical arrangements, preparatory to the final establishment of those boundaries. He was engaged to perform this service, by the Rev. Mr. Richard Peters, (afterwards D. D. and rector of the united churches of Christ-Church and St. Peters, in Philadelphia,) who then officiated as the Governor’s provincial secretary; a gentleman of learning and great worth; and one who, on various occasions, manifested a friendship for Mr. Rittenhouse, as well the high opinion he entertained of his abilities.

The particular department of that business thus committed to Mr. Rittenhouse, seems to have been the fixing of the Circle,—or at least, the tracing of its course or route, topographically; and this was, certainly, a matter of no little difficulty. That this service was performed to the satisfaction of the then administrators of the government of Pennsylvania, and that it was an arduous one, will appear by the following extract of a letter from Mr. Rittenhouse to the Rev. Mr. Barton, dated the sixteenth of February, 1764.^[101]

147“I hope,” said he, “you will never believe that I am determined to disclaim all kind of intercourse” with 148you: for I can say with the greatest sincerity there are very few things I so much regret, as that I have it 149not in my power to spend a great part of my time with you. My attention has, for some time past, been engaged 150with such a multiplicity of things, that I may with some reason claim your indulgence for my not writing. Have I not, indeed, an equal right to complain?—for, I think this letter will balance our accounts, from the time I last saw you.

“I waited on Mr. Peters, as you desired me to do. He treated me kindly, and made an offer of doing me some services; for which I am greatly obliged to him. He likewise paid me for my attendance at New-Castle, and much more generously than I expected;—though I found it a very laborious affair; being obliged, singly, to go through a number of tedious and intricate calculations.”

151It appears that about this time, Mr. Rittenhouse’s friends had some beneficial object in view for him; perhaps some official situation, which they conceived to be adapted to the nature of his pursuits, and such as might more permanently promote his interests. But whatever that object may have been, he seems to have hesitated about it. If it were a public appointment of a permanent kind, it would probably have required his removal to the city,—a measure which he did not contemplate at that time; and he might, besides, have been disinclined to undertake any official duties, which would be likely to occupy the greater part of his time. He expressed himself thus to Mr. Barton, on the subject, in the letter just quoted:—“I am greatly obliged to you, my dear brother, for pointing out any prospect of advantage to me: I shall consider the matter you mention in your last, and let you know my opinion. The objections you have so well answered, are those which would most readily occur to me. Considering the crazy state of my constitution, a retired life would certainly suit me best. Since death, to use John Bunyan’s^[102] phrase, 152does usually knock at my door once a day, would it not be a folly for me to take up the load of any public business?”

About three years afterwards, Mr. Rittenhouse seemed to have been less indisposed to accept of an official situation: and, such was his high standing with the government and its most influential friends, there can be very little doubt he could have obtained a respectable one. It is evident that, at this latter period, when perhaps his health was improved, he 153had some particular office in view: because, by a letter to Mr. Barton, dated January 28th 1767, he said—“I am entirely satisfied with your proceedings in the affair I recommended to you; and I shall wait on Mr. Peters. The reputation of the office would be very agreeable to me; but the execution of it would, I am afraid, greatly interfere with the other projects you have so much insisted on.”

Mr. Rittenhouse continued a bachelor until the 20th of February, 1766, when he married Eleanor Colston, daughter of Bernard Colston, a reputable farmer in the neighbourhood. This person belonged to the religious society called Quakers; Mr. RittenhouseRittenhouse was not himself a member of any particular church: but the marriage was solemnized at Norriton, by the Rev. Mr. Barton, who went thither for the purpose at his brother-in-law’s request.

Some time prior to this event, old Mr. Rittenhouse, having previously made his son David the proprietor of the Norriton farm, removed with his family to the house he had built^[103] on his place in Worcester township, already mentioned; while the son’s family occupied the old place of residence: and here our Astronomer remained about four years after his marriage. It was during this period, that his reputation as an 154astronomer became eminently conspicuous;^[104] his name acquired a celebrity even in the old world, of which his early but now much increased fame, in his native country, was a sure presage.^[105]

155About the time that he projected his Orrery (which shall be duly noticed in its place), it appears he had been speculating on the doctrine of the compressibility of water. For in a letter to Mr. Barton, dated from Philadelphia the 27th of March, 1767, he mentions,—that he had not then met with any person, who had seen Mr. Kinnersley’s^[106] experiment on that theory; 156but that he understood it was made with the air-pump, and conjectured it to have been similar to the one made by a member of the Royal Society, related in Martin’s Magazine: which is thus quoted in Mr. Rittenhouse’s letter:

“I took a glass ball of about an inch and ⁶/₁₀ in diameter, which was joined to a cylindrical tube of 4 inches and ²/₁₀ in length, and in diameter ¹/₁₀₀ of an inch; and by weighing the quantity of mercury that exactly filled the ball, and also the quantity that filled the tube, I found that the mercury in ²³/₁₀₀ of an inch of the tube was the 10000th part of that contained in the ball; and with the edge of a file, I divided the tube accordingly. This having been done, I filled the ball and part of the tube with water exhausted of air: Now, by placing this ball and tube under the receiver of an air-pump, I could see the degree of expansion of the water, answering to any degree of rarefaction of the air; and by putting it into a glass receiver of a condensing engine, I could see the degree of compression of the water, answering to any degree of condensation of the air, &c.”—Then adds. Mr. Rittenhouse—“Indeed I do not doubt the compressibility of water, although the above experiment does 157not much please me. If the particles of water were in actual contact, it would be difficult to conceive how any body could much exceed it in specific gravity; yet we find that gold does, more than eighteen times.”

The first academic honour conferred upon our philosopher, was on the 17th of November, 1767; when the College of Philadelphia, then in its meridian splendour, bestowed on him an honorary degree of Master of Arts. Mr. Rittenhouse being present at the commencement then held, the provost, in conferring this degree, thus addressed him,—in terms of a just and well merited compliment:

“Sir,—The trustees of this College (the faculty of professors cheerfully concurring), being ever desirous to distinguish real merit, especially in the natives of this province,—and well-assured of the extraordinary progress and improvement which you have made, by a felicity of natural genius, in mechanics, mathematics, astronomy, and other liberal arts and sciences, all which you have adorned by singular modesty and irreproachable morals,—have authorized and required me to admit you to the honorary degree of Master of Arts, in this seminary: I de therefore, by virtue of this authority, most cheerfully admit, &c.”

Mr. Rittenhouse’s great abilities, as an astronomer and mathematician, being now every where known, 158he was employed in the year 1769, in settling the limits between the provinces of New-York and New-Jersey. The original grant of all the territory, called by the Dutch New-Netherlands (sometimes Nova-Belgia), was made by King Charles II. to James Duke of York, on the 12th of March, 1663-4; and on the 24th of June following, the Duke granted that part of it, now called New-Jersey, to the Lord Berkeley of Stratton and Sir George Carteret, jointly. The Dutch reduced the country, in the year 1672; but it was restored by the peace of Westminster, February the 9th, 1673-4. On the 29th of June, in the same year, a new patent was issued to the Duke of York, for the lands comprised within the limits described in the former patent. On the 28th of the succeeding July, the colony of New-Jersey was divided into East and West-Jersey (hence, generally called the Jersies); and the former was then granted, by the Duke of York, to Sir George Carteret. In 1675, West-Jersey, being Lord Berkeley’s moiety of the province, was sold to John Fenwick, in trust for Edward Bylinge; who assigned his interest therein to William Penn and others,^[107] in trust, for the use 159of his creditors. This partition was confirmed in the year 1719, by the general assembly of the Jersies. But prior to this confirmation, viz. the 10th of October, 1678, a new grant of West-Jersey was made by the Duke of York, to the assigns of Lord Berkeley; and on the 1st of February, 1681-2, East-Jersey was sold and conveyed, in pursuance of Sir George Carteret’s will, to twelve persons; who, by separate deeds, conveyed one-half of their several interests in the same to twelve other persons: and, on the 14th of the next month, the Duke of York made a new grant of East-Jersey to those twenty-four proprietors, thereby confirming the same to them. The proprietors of both the Jersies afterwards became very numerous, by purchase as well as by descent. This being attended with great inconveniencies, they finally surrendered the government to the crown, on the 17th of April, 1702: and from that time, the province of New-Jersey continued to be a royal government, until the American revolution.

160The division-line, between East and West-Jersey, was to run from the south-east point of Little Egg-Harbour, on Barnegate Creek—being about midway between Cape-May and Sandy-Hook, to a creek, a little below Ancocus-Creek, on the river Delaware; thence, about thirty-five miles in a straight course, along the Delaware, up to 44° 40´ of north latitude.

The province of New-York passed a legislative act on this subject, in the year 1762; and the New-Jersey Assembly enacted a corresponding law, in 1764. Five commissioners—namely, John Stevens, James Parker, Henry Cuyler, William Donaldson, and Walter Rutherford—were appointed on this business, for the two provinces: their report was passed upon, by both; and it was confirmed by the King in council, the 1st of September, 1773. It is understood, that the division-line between East and West-Jersey remained unsettled, so late as the year 1789. But it nevertheless appears, that the territorial boundary between New-York and New-Jersey was fixed by Mr. Rittenhouse, forty-four years ago.

A recurrence shall now be had to a date anterior to our Philosopher’s employment in the transaction just mentioned.—Within the two years preceding that period, two objects of much importance to astronomical science, claimed a large share of the public attention, in this country: One of them, especially, had already actually engaged the investigations of the 161ablest astronomers of the other hemisphere, as well as our own; preparatory to the then approaching event, to which those researches were directed. The result of the expectations excited by both of those objects proved, on their final completion, highly honourable to the fame of Mr. Rittenhouse.

The first of these, in the order of time, was our Astronomer’s newly-projected Orrery; a general but concise description of which, was communicated by his friend, the Rev. Dr. Smith, to the Philosophical Society, on the 21st of March, 1768. Of this fine and eminently useful piece of mechanism, more particular mention shall be made in the sequel.

The other circumstance, just referred to, was the then approaching Transit of Venus over the Sun’s disk; an event which was to take place on the 3d day of June, 1769: And of Mr. Rittenhouse’s participation in the arduous labours of the astronomical world, on that very interesting occasion, the following narrative will furnish some account.

The American Philosophical Society, in their meeting on the 7th of January, 1769, had appointed the following gentlemen to observe that rare phænomenon,^[108] as it was aptly styled by Dr. Smith; namely, 162the. Rev. Mr. (afterwards Dr.) John Ewing, Mr. Thomas Prior, Joseph Shippen, jun. Esq., Hugh Williamson, M. D., the Rev. Dr. Smith, Mr. David Rittenhouse, John Lukens, Esq. and Messrs. James Alexander, Owen Biddle, James Pearson, John Sellers, Charles Thomson, and William Poole. The gentlemen thus nominated were distributed into three committees, for the purpose of making separate observations at three several places; these were, the city of Philadelphia, Mr. Rittenhouse’s residence, in Norriton, and the Light-House near Cape Henlopen, on Delaware Bay. Dr. Ewing, an able mathematician and very respectable astronomer, had the principal direction of the Observatory in the City, which was erected on this occasion in the State-house Gardens; and Mr. O. Biddle, a person of much ingenuity, had the charge of superintending the observations at Cape Henlopen. Associated with Mr. Rittenhouse, on the Norriton committee, were the Rev. Dr. Smith, provost of the College of Philadelphia, well known as an astronomer and eminently skilled in the mathematics; Mr. Lukens, then surveyor-general 163of Pennsylvania, who possessed considerable abilities in the same departments of science; and Mr. Sellers, a respectable member of the provincial legislature, for the county of Chester. The Rev. Mr. Barton, with some other gentlemen of ingenuity and talents, voluntarily attended at Norriton, on this occasion; and rendered such assistance as they could, to the committee.

As the time approached near, when this extraordinary and almost unprecedented^[109] astronomical phænomenon was to manifest itself, the public expectation and anxiety, which were before considerable, became greatly heightened. The ignorant—and those, generally, unacquainted with the nature of the looked-for event,—hearing much every where said on the subject, and seeing the preparations making for the occasion, had their curiosity wonderfully excited. To scientific men, the inestimable value of the approaching phænomenon suggested very different sensations. “Its importance to the interests of Astronomy and Navigation, had,” as Dr. Ewing observed at the time, “justly drawn the attention of every civilized nation in the world.” An accurate ascertainment 164of the Sun’s Parallax,—an important. and fundamental article in Astronomy, was a desideratum not yet obtained. Only two Transits of Venus over the Sun, had been observed, prior to the 3d of June, 1769, since the creation of the world; and of these, the first alone was seen but by two persons:^[110] Yet, as the learned gentleman just quoted has remarked,—“the Transits of Venus, alone, afford an opportunity of determining this problem” (the settling the Parallax of the Sun,) “with sufficient certainty: and these,these,” he adds, “happen so seldom, that there cannot be more than two in one century, and in some centuries none at all.”

To an object, then, of such vast importance to science, were proportioned the expectations of our Observers. But they could not fail to experience, at the same time, in common with their astronomical brethren in other parts of the world, a large portion of anxious apprehensions, lest a cloudy day—nay, even a solitary passing cloud,—should baffle entirely their exalted hopes, and destroy all the fruits of their arduous labours! Yet such an occurrence, as one or the other of these events, was evidently within the calculations of a probable incident.

Mr. Rittenhouse participated largely in these blended hopes and fears. He had, for some time before, 165been laboriously employed in making the requisite preparatory observations and calculations: and, as Norriton was now rendered eminently conspicuous, by being fixed on as a principal site for observing the very interesting phænomenon so near at hand, he had been assiduously engaged, at the same time, in preparing and furnishing an Observatory at that place, suitable for the occasion. This he began to erect early in November, 1768,—“agreeably,” to use his own words, “to the resolutions of the American Philosophical Society;” but, through various disappointments from workmen and weather, he was not enabled to complete it till the middle of April, 1769.^[111]

166The Norriton Observatory was commodiously situated near Mr. Rittenhouse’s mansion, on a pretty elevated piece of ground, commanding a good range of horizontal view. This temporary edifice was as well adapted to the purpose for which it was chiefly designed, as the nature of the materials of which it was constructed, and other circumstances, would permit. Some monies had been previously appropriated by the Philosophical Society, towards defraying the expenses necessarily incident to this occasion, at the three several places of observation: but the funds of the society, at their disposal for such purposes, were very limited; and it is believed that the quota of these funds assigned for the expenditures actually incurred for making the observations of the transit, at Norriton, was quite inconsiderable in its amount.

In order that ample justice may be done to the merits of Mr. Rittenhouse, for all the preparatory arrangements made by him on this occasion, the reader 167is here presented with an extract from Dr. Smith’s subsequent Report, to the Philosophical Society, of the proceedings of the Norriton Committee, and made in their behalf.—“I am persuaded” says the doctor, “that the dependance which the learned world may place on any particular Transit-Account, will be in proportion to the previous and subsequent care, which is found to have been taken in a series of accurate and well conducted observations, for ascertaining the going of the time-pieces, and fixing the latitude and longitude of the place of observations, &c. And I am the more desirous to be particular in these points, in order to do justice to Mr. Rittenhouse, one of the committee; to whose extraordinary skill and diligence is owing whatever advantage may be derived, in these respects, to our observation of the Transit itself.”—“Our great discouragement at our first appointment,” continues the learned reporter, “was the want of proper apparatus, especially good Telescopes with Micrometers. The generosity of our Provincial Assembly soon removed a great part of this discouragement, not only by their vote to purchase one of the best reflecting Telescopes, with a Dollond’s micrometer;^[112] but likewise 168by their subsequent donation of one hundred pounds,” (this was in sterling money, = $444) “for erecting Observatories and defraying other incidental expences.^[113] It was forseen, that on the arrival of the Telescope, added to such private ones as might be procured in the city, together with fitting up the instruments belonging to the honourable the Proprietaries of the province—viz. the equal Altitude and Transit Instruments and the large astronomical Sector,—nothing would be wanted for the city Observatory in the State-House Square, but a good Time-piece, which was easily to be procured. We remained, however, still at a loss, how to furnish the Norriton Observatory:^[114] But even this difficulty gradually vanished.”

169Thus it appears, that while the public contributions, and such astronomical instruments suitable for the occasion as were the public property, were principally at the disposal of the Philadelphia committee, the Observatory at Norriton—which seems to have been considered as a private establishment, belonging to an individual,—depended almost entirely on other resources. Even an excellent reflecting telescope (though without a micrometer,) the property of the Library Company of Philadelphia, and to which institution it was a donation from the Hon. T. Penn,—the same that had been used by Messrs. Macon and Dixon, when employed in settling the boundary lines of Pennsylvania and Maryland—was necessarily appropriated to the use of Mr. Owen Biddle, who was appointed by the Society to conduct the Observation of the Transit, near Cape Henlopen.

The Norriton Observatory was, notwithstanding, at last completely furnished with every instrument proper for the occasion. In consequence of some previous communications made by Dr. Smith to the Hon. Mr. T. Penn of London, and to the Rev. Mr. Maskelyne, the British astronomer-royal at Greenwich, the former worthy and liberal gentleman had sent, for the use of the Norriton committee, a reflecting Telescope with Dollond’s Micrometer—such as the doctor had expressed a wish to obtain; and requested, that after the committee should have made their observations with it, it should be presented in his name to the 170College.^[115] Through the means of Dr. Smith, likewise, an astronomical quadrant of two and an half feet radius, made by Sisson, the property of the East-Jersey proprietaries, was procured by Mr. Lukens from the Earl of Stirling, surveyor-general of that province. This had been pretty early sent up by Mr. Lukens to Mr. Rittenhouse, and was used by him in ascertaining the latitude of his Observatory.

In addition to these and some other apparatus used at Norriton on the occasion—a catalogue and description of the whole of which, are contained in Dr. Smith’s before-mentioned report—the zeal, industry, and talents of Mr. Rittenhouse enabled him to furnish his Observatory with the three following described instruments, made by himself,^[116] as described by Dr. Smith.

1711. An Equal Altitude Instrument—its telescope three and an half feet focal length, with two horizontal hairs, and a vertical one in its focus; firmly supported on a stone pedestal, and easily adjusted to a plummet-wire four feet in length, by two screws, one moving in a North and South, the other in an East and West direction.

2. A Transit Telescope, fixed in the meridian, on fine steel points; so that the hair in its focus could move in no other direction than along the meridian; in which were two marks, South and North, about 330 yards distance each; to which it could be readily adjusted in an horizontal position by one screw, as it could in a vertical position, by another.

3. An excellent Time-piece—having for its pendulum-rod a flat steel bar, with a bob weighing about twelve pounds, and vibrating in a small arch. This went eight days, did not stop when wound up, beat 172dead seconds, and was kept in motion by a weight of five pounds.^[117]

Thus was the Norriton Observatory furnished with all the more immediately necessary apparatus, in readiness for the important event which was the main object of these arduous exertions. Much credit was due to Dr. Smith, much to Mr. Lukens and the other gentlemen engaged on this occasion, for the assistance which he, and they, afforded Mr. Rittenhouse. Yet the doctor himself very candidly says—in reporting the proceedings of the Norriton committee to the Philosophical Society,—“other engagements did not permit Mr. Lukens or myself to pay much attention to the necessary preparations; but we knew that we had entrusted them to a gentleman on the spot, who had joined to a complete skill in mechanics, so extensive an astronomical and mathematical knowledge, that the use, management, and even the construction of the necessary apparatus, were perfectly familiar to him. Mr. Lukens and myself could not set out for his house till Thursday, June 1st; but, on our arrival there, we found every preparation so forward, that we had little to do, but to adjust our respective telescopes to distinct vision. He had fitted up the different instruments, and made a great number of observations, to ascertain the going of his Time-piece, and to determine the latitude and longitude of his Observatory. The laudable 173pains he hath taken in these material articles,” continues Dr. Smith in his report, “will best appear from the work itself,—which he hath committed into my hands, with the following modest introduction; giving me a liberty, which his own accuracy, care and abilities, leave no room to exercise.”^[118]

174

Norriton, July 18th 1769.

“Dear Sir,

“The enclosed is the best account I can give of the Contacts, as I observed them; and of what I saw during the interval between them. I should be glad you would contract them, and also the other papers, into a smaller compass,—as I would have done myself, if I had known how. I beg you would not copy any thing merely because I have written it, but leave out what you think superfluous.—I am, with great esteem and affection, yours, &c.

David Rittenhouse.^[119]

To Rev. Dr. Smith.”

175The result of the Norriton Observations of the Transit of Venus—as well as those also made under the auspices of the American Philosophical Society, at Philadelphia and Cape Henlopen—will be found, in detail, in the first volume of the Transactions of that Society.^[120] And “the Work itself,” to which 176Dr. Smith refers, in his Report of the Proceedings of the Norriton Committee, bears ample testimony to the 177transcendent Astronomical Abilities of Mr. Rittenhouse.—Four days after the Transit, Dr. Smith transmitted to the Hon. Mr. Penn, in London, a short account of the Norriton Observations, more particularly mentioning the times of the Contacts, and a few other circumstances attending them. This was speedily communicated by Mr. Penn to the Rev. Mr. Maskelyne,^[121] the Astronomer Royal; who, acknowledging 178the receipt of the communication, by a note, dated at Greenwich the 2d of August, 1769, says—“I thank you for the account of the Pennsylvania Observations (of the Transit,) which seem excellent and complete,^[122] and do honour to the gentlemen who made them^[123], and those who promoted the undertaking;— 179among whom, I reckon yourself^[124] in the first place.”^[125]

180Here the observation will emphatically apply;—Laus est, â viro laudato laudari.

181Before this interesting occurrence in the life of Mr. Rittenhouse is finally passed over, the reader’s 182attention is solicited to the beautiful and animated description given by Dr. Rush, in his Eulogium, of the sensations which must have been more particularly experienced by that extraordinary man, on the near approach of the long-expected Phænomenon.—“We are naturally led here,” says the learned Professor, “to take a view of our Philosopher, with his associates, in their preparations to observe a phænomenon which had never been seen but twice^[126] before, 183by any inhabitant of our earth, which would never be seen again by any person then living, and on which depended very important astronomical consequences. The night before the long-expected day, was probably passed in a degree of solicitude which precluded sleep. How great must have been their joy, when they beheld the morning sun!—‘and the whole horizon without a cloud;’ for such is the description of the day, given by Mr. Rittenhouse, in the report referred to by Dr. Smith. In pensive silence and trembling anxiety, they waited for the predicted moment of observation: it came,—and brought with it all that had been wished for, and expected, by those who saw it.—In our Philosopher, it excited—in the instant of one of the contacts of the planet with the sun, an emotion of delight so exquisite and powerful, as to induce fainting. This,” then remarks Dr. Rush, “will readily be believed by those who have known the extent of that pleasure which attends the discovery, or first perception of Truth.”

On the 9th of November, following, there was a Transit of Mercury over the Sun. An account of this phænomenon,—as observed at Norriton by William 184SmithSmith, d. d. John Lukens, Esq. and Messrs. David Rittenhouse and Owen Biddle, the Committee appointed for that Observation by the American Philosophical Society,—was drawn up and communicated to the Society, by direction and in behalf of the Committee, by Dr. Smith: this will be found in the first volume of the Society’s Transactions. In this report it is remarked, that—“the first time that ever Mercury was observed on the Sun’s disk, was by Gassendus at Paris, October 28th 1631, O. S. and that the Transit of Nov. 9th was the fourth in that class; the two intermediate ones, each at forty-six years distance, having been observed by Dr. Halley, in 1677 and 1723.”

Mr. Maskelyne, the celebrated English Astronomer before mentioned,^[127]—in a letter to Dr. Smith, of the 26th of December, 1769—expressed a wish “that the 185difference of Meridians of Norriton and Philadelphia, could be determined by some measures and bearings, within one-fiftieth or one-hundredth part ofof the whole; in order to connect,” continues Mr. Maskelyne, “your observations of the Longitude of Norriton with those made by Messrs. Mason and Dixon, in the course of measuring the degree of Latitude.”—This request of the Astronomer Royal was communicated to the Philosophical Society of Philadelphia; in consequence of which, Dr. Smith, Mr. Lukens and Mr. Rittenhouse, were appointed to make the terrestrial measurement required. These gentlemen, having taken to their assistance Mr. Archibald M’Clean and Mr. Jesse Lukens, two able and experienced Surveyors, commenced their operations at Norriton, early on the 2d day of July following, and completed their survey on the 4th day of that month. The Report of the able Committee, to which this business was assigned by the American Philosophical Society, is also contained in the first volume of the Transactions of that learned Body. After giving various calculations, resulting from the operations of that committee, the Reporter says—“Hence, by the above measurement and work, we get Norriton Observatory 52″ of time West of the Observatory in the State-house Square; which is exactly what we got by that excellent element, the external contact of Mercury with the Sun, Nov. 9th 1769.”—“The external contact,” continues the Reporter, “gave it something more; owing, no doubt, to the difference that will 186arise among Observers, in determining the exact moment when the thread of light is compleated: and the mean of all our Observations gives the difference of Meridians, between Norriton and Philadelphia, only 4″ of time more than the terrestrial measurement, and the external contact of Mercury, gave it,—which may be taken as a very great degree of exactness; if we consider that the difference of Meridians, between the long-established Observatories of Greenwich and Paris, (as Mr. De la Lande writes, Nov. 18th 1762,) was not then determined within 20″ of time—For, he says, ‘some called it 9′ 15″; others, 9′ 40″;’ but that he himself commonly used 9′ 20″, though he could not tell from what Observations it was deduced.^[128]—Finally, the Report fixes Philadelphia to be 5^h 0′ 37″, and Norriton, 5^h 1′ 29″ West from Greenwich.^[129] The Latitude of Norriton, as deduced from the actual mensuration just mentioned, connected with Observations previously made by Mr. Rittenhouse—predicated also, 187in part, on antecedent Calculations of Messrs. Mason and Dixon, who, (having been furnished with a complete Astronomical Sector,) had ascertained the southernmost point of the City of Philadelphia to be in Latitude 39° 56′ 29″,4. N.—is stated, in the same Report, as being 40° 9′ 31″. It came out, by the measurement, 25″.09 less North, with respect to the southernmost point of Philadelphia, than Mr. Rittenhouse’s Observations had given it; and, in making these, he had no better Instrument than Sisson’s two-and-an half feet Quadrant. Nevertheless, the framer of the Report remarks, “as both were fixed by celestial observations and experienced Men, the small difference ought perhaps to be divided; and if a mean be taken, to reconcile it with the terrestrial measure, the Lat. of the south point of Philadelphia would be 39° 56′ 42″; and that of Norriton, 40° 9′ 43″.^[130]

The same Volume of the American Philosophical Transactions that comprehends the communications of these Proceedings—as well as various Observations, made at different places, on the then recent Transit of Venus—contains also a Memoir, by Dr. Smith, deducing the Sun’s Parallax from a comparison of the Norriton and some other American Observations of the Transit of Venus, in 1769, with the Greenwich 188and some other European Observations of the same: And with this paper, its learned writer has incorporated a communication, on the same subject, made to him by Mr. Rittenhouse.

Until about the period at which the latest of these favourite transactions of Mr. Rittenhouse took place—namely, his geometrical employment in ascertaining the Latitude and Longitude of Norriton and Philadelphia, respectively,—he continued to reside on his farm at Norriton. And here he still carried on, with the aid of some apprentices and journey-men, his self-acquired occupation of a Clock and Mathematical Instrument-maker: combining, at intervals, with these mechanical pursuits, an unceasing attention to his philosophical studies and researches; and occasionally employing himself, principally with a view to his health, in some of the occupations of Husbandry. Ever an economist of Time, of which he well knew the inestimable value, none of his hours which could be spared from necessary sleep were suffered to be unemployed. In this rural abode, he enjoyed the comforts of domestic life amidst his little family, consisting only of an amiable wife and two young children. In short, no part of his time was unengaged, or uselessly passed; although he, not unfrequently, felt the solace of friendly calls, and was gratified by visits from persons of science, worth, and distinction.

189The writer of these memoirs designed to narrate those circumstances most worthy of notice, in the Life and character of Mr. Rittenhouse, in their chronological order; and this plan will be generally adhered to. Having followed our philosopher in his astronomical and mechanical pursuits, up to the year 1770, it therefore becomes proper to recur to a period of his life some few years earlier, in order to introduce the history of his Orrery,^[131] before mentioned; a piece of 190mechanism which is admitted, by all competent judges of its merit, to be one of the greatest of his works.

The Planetarium invented by Mr. George Graham,^[132]—and a model of which was improperly retained by Mr. Rowley, its constructor,—had, long before the appearance of Mr. Rittenhouse’s machine, acquired the name of an Orrery; in compliment to Richard Boyle, Earl of Orrery,^[133] who merely patronized the construction of one, from the artist Rowley’s pirated model. This complimentary appellation of Mr. Graham’s then newly invented Planetarium is 191said to have been bestowed upon it by Lord Orrery’s friend, Sir Richard Steele:^[134] and, the name being thus applied to that machine, all those of the nature of Planetaria, subsequently constructed,—however variant in usefulness or design, from the original one bearing the name of an “Orrery,”—were denominated Orreries.^[135] In compliance, then, with long established 192usage, Mr. Rittenhouse modestly called his Planetarian-machine, from the first projection of it, an Orrery; although the entire merit, both of the invention and construction, belonged to himself.^[136]

It is not ascertained, at what time Mr. Rittenhouse first conceived the plan of that extensive, complicated and inestimable Orrery, which he afterwards executed. Probably, he had long thought on the subject, before he publicly announced his design. It is certain, however, that before the beginning of the year 1931767, there was some correspondence and some understanding, respecting it, between himself and the Rev. Mr. Barton. It appears in fact, that, prior to that period, Mr. Barton had been fully apprized of his brother-in-law’s desire to carry into effect his meditated design of constructing a complete Orrery, on a plan entirely new; and that some arrangement was previously made, between these gentlemen; by which Mr. Barton undertook to indemnify Mr. Rittenhouse, for such actual expenditures as he should incur in making the machine and his loss of time while employed in the work, not exceeding a stipulated sum; provided he should not be able to dispose of it, when finished, at a price then fixed on. The prudential caution of our young Philosopher (then about thirty-four years of age,) and the public spirit of his friend, grounded on the confidence he had in the artist’s talents and abilities, were alike evinced on this occasion.

The first written communication made by Mr. Rittenhouse to Mr. Barton, on the subject of the Orrery, is contained in a letter under the date of Jan. 28th, 1767: it is in these words:—“I am glad you took the pains to transcribe, and send me, Martin’s Account of Orreries.”^[137] “Two forms (he says) have principally obtained, the Hemispherical Orrery and the Whole Sphere. But the idea given us by the former, 194is very unnatural and imperfect. An Orrery, then, adapted to an Armillary Sphere is the only machine that can exhibit a just idea of the true System of the World.”—“But in my opinion,” says Mr. Rittenhouse, “the latter is likewise very unnatural; for, what has a Sphere, consisting of a great number of metaline Circles, to do with the true System of the World? Is there one real, or so much as apparent Circle, in it? (the bodies of the Sun and Planets excepted.) Are they not all merely imaginary lines, contrived for the purpose of calculation? I did not intend to let one of them have a place in my Orrery, except the Zodiac, on which I would have the true latitude and longitude of each planet pointed out by its proper Index.”

“I did not design a Machine, which should give the ignorant in astronomy a just view of the Solar System: but would rather astonish the skilful and curious examiner, by a most accurate correspondence between the situations and motions of our little representatives of the heavenly bodies, and the situations and motions of those bodies, themselves. I would have my Orrery really useful, by making it capable of informing us, truly, of the astronomical phænomena for any particular point of time; which, I do not find that any Orrery yet made, can do.”

“But,” continues Mr. Rittenhouse, “perhaps it may be necessary to comply with the prevailing taste: If 195so, my plan must be entirely altered;—and this is a matter that must be settled between you and me, before I can proceed. However, I shall send you, in my next, a particular account of my design; such as I would have it, if not limited by the fear of making it too expensive.—A specimen (if I may so call it) of the most curious part of it, though much smaller than that intended for the Orrery, is now in hand, and I hope will soon be finished.”

To this letter Mr. Barton returned the following answer.

“Lancaster, February 21st, 1767.

“Dear Brother,

“I received, a few days ago, yours of the 28th ult.—after it had undergone the torture of some Dutchman’s pocket, which compelled it to force its way through the cover: However, the inside did escape without many fractures; so that I had the pleasure of getting it into my hands in such a condition that I could read it.

“Had I known your distress, at the time you received my letter, I should have sincerely felt for you. I well know the anxiety of an husband, on such occasions, and my heart will ever join in sympathy with him: For you, my feelings would have been doubled, as a husband, as my friend and brother. Glad I am, therefore, that I have no occasion to condole with you, but rather to rejoice; and I most sincerely and affectionately congratulate you, on the escape and recovery 196of your good girl, and wish you joy of your daughter. I desire to offer my best regards to sister Nelly, for the compliment she intended me, had her child been a boy. Her intention was kind, and I hope to have the continuance of her favourable opinion of me.

“I am much pleased with your remarks on Spherical Orreries, or rather on the circles generally adapted to such Orreries. Mr. Rowning seems to be so much of the same opinion, that I could not deny myself the pleasure of transcribing some part of his account of Orreries, and of an imaginary machine, which he thinks might be made very useful.^[138] Several of his hints appear to me ingenious, and I hope they will not be unacceptable to you.

“I would have you pursue your Orrery in your own way, without any regard to an ignorant or prevailing taste. All you have to study is truth, and to display the glorious system of Copernicus in a proper manner;—and to make your machine as much an original, as possible. I beg you will not limit yourself in the price. I am now perfectly convinced, that you can dispose of it to advantage; and should be sorry you would lose one hour more in fears or doubts about it. In fact, I have laid such plans for the disposal of it, that I have almost a moral certainty of having a demand for more than one of the kind. I have not time to write you as fully as I could wish, as the transcribing 197from Rowning has detained me so long, and I am this moment setting out for Caernarvon.

“My letter to the Proprietor^[139] is delayed, till I can send him the account of your design, which you are pleased to promise me. You say you have “a specimen” in hand: I should be glad to know what it is.

“I shall not neglect the things you mentioned to me, as I shall always receive a pleasure in serving you.... She joins me in love to father, mother and all friends.—I am, in haste, dear Davy, your very affectionate friend and brother,

“Thomas Barton.

“P. S. Forgive this wretched scrawl—I have not time to examine whether I have committed any errors in copying Mr. Rowning.

“I beg leave to recommend Huygens’, Cotes’, Helsham’s, and Power’s Philosophy to you. You will be much pleased with them.

198“I wish you would purchase Bion’s Description of Philosophical and Mathematical Instruments, &c.”

“Mr. David Rittenhouse.”

His next letter to Mr. Barton, covering the promised Account of his Orrery, is dated the 27th of March, 1767: and this, it will be perceived, is very nearly a year before a description of it was communicated to the American Philosophical Society in Philadelphia. In this letter, he says—“Rowning’s opinion of Orreries pleases me more than any thing I had met with before. The idea of his imaginary machine naturally presents itself to persons conversant in Astronomy; but, if actually made, it could not answer the purpose, unless prodigiously large,—which I presume is the reason it has never been done.done.

“I send“I send you a description of my imaginary machine: the foundation of it is now laid; and I hope that part of it, containing the mechanical Astronomy of the Moon, will be finished some time this spring: then we shall be able to judge, whether my abilities are equal to the undertaking.”

The “Description” here referred to, in Mr. Rittenhouse’s own hand-writing, is new before the writer of these Memoirs; and is thus endorsed by the Rev. Mr. Barton—“Original Description of Mr. 199Rittenhouse’s Orrery, first communicated to Thomas Barton.”—For the satisfaction of those, who may not have an opportunity of seeing the American Philosophical Society’s Transactions, in which this short account of the Orrery was afterwards published; and, as this original description of it differs somewhat from the printed one, it is presumed that the introduction of the former into this work, will not be unacceptable to the reader.

The impossibility of conveying to the mind of any one, even the most intelligent and skilful, by means of either any delineation upon paper in the nature of a diagram, or by words, an adequate idea of so complex and multiform a machine as the one now about to be described, will instantly be conceived. Indeed no description, alone, can render the nature of its construction, and the many curious and useful purposes it is capable of answering, perfectly intelligible to the most scientific Astronomer. Mr. Rittenhouse’s very concise description of his Orrery will, therefore, necessarily be found defective: it is thus worded by himself.

“DESCRIPTION OF A NEW ORRERY.

“This Machine is intended to have three faces, standing perpendicular to the horizon: that in the 200front to be four feet square, made of sheet-brass, curiously polished, silvered, and painted in proper places, and otherwise ornamented. From the centre arises an axis, to support a gilded brass ball, intended to represent the Sun. Round this ball move others, made of brass or ivory, to represent the Planets: They are to move in elliptical orbits, having the central ball in one focus; and their motions to be sometimes swifter, and sometimes slower, as nearly according to the true law of an equable description of areas as is possible, without too great a complication of wheel-work. The orbit of each Planet is likewise to be properly inclined to those of the others; and their Aphelia and Nodes justly placed; and their velocities so accurately adjusted, as not to differ sensibly from the tables of Astronomy in some thousands of years.

“For the greater beauty of the instrument, the balls representing the planets are to be of a considerable bigness; but so contrived, that they may be taken off at pleasure, and others, much smaller, and fitter for some purposes, put in their places.

“When the Machine is put in motion, by the turning of a winch, there are three indexes which point out the hour of the day, the day of the month, and the year (according to the Julian account,) answering to that situation of the heavenly bodies which is then represented; and so continually, for a period of 5000 years, either forward or backward.

201“In order to know the true situation of a Planet at any particular time, the small set of balls are to be put each on its respective axis; then the winch to be turned round until each index points to the given time. Then a small telescope, made for the purpose, is to be applied to the central ball; and directing it to the planet, its longitude and inclination will be seen on a large brass circle, silvered, and properly graduated, representing the zodiac, and having a motion of one degree in seventy-two years, agreeable to the precession of the equinoxes. So, likewise, by applying the telescope to the ball representing the earth, and directing it to any planet,—then will both the longitude and latitude of that planet be pointed out (by an index and graduated circle,) as seen from the earth.

“The two lesser faces are four feet in height, and two feet three inches in breadth. One of them will exhibit all the appearances of Jupiter and his Satellites—their eclipses, transits, and inclinations; likewise, all the appearances of Saturn, with his ring and satellites. And the other will represent all the phænomena of the moon, particularly, the exact time, quantity, and duration of her eclipses—and those of the sun, occasioned by her interposition; with a most curious contrivance for exhibiting the appearance of a solar eclipse, at any particular place on the earth: likewise, the true place of the moon in the signs, with her latitude, and the place of her apoge in the nodes; the sun’s declination, equation of time &c. It must 202be understood, that all these motions are to correspond exactly, with the celestial motions; and not to differ several degrees from the truth, in a few revolutions, as is common in Orreries.

“If it shall be thought proper, the whole is to be adapted to, and kept in motion by, a strong pendulum-clock; nevertheless, at liberty to be turned by the winch, and adjusted to any time, past or future.”

“N. B. The diurnal motions of such planets as have been discovered to revolve on their own axes, are likewise to be properly represented; both with regard to the Times, and the situation of their Poles.”

The foregoing is a literal copy of the original manuscript; and such readers of this article as may think proper to compare it with the printed description of Mr. Rittenhouse’s Orrery, communicated to the American Philosophical Society by Dr. Smith, on the 21st of March 1768, and contained in the first volume of that Society’s Transactions, will find some (though, on the whole, not very essential) differences, in the two descriptions. The concluding paragraph, indeed,—designated, in each, by a N. B.—is materially variant in the two: and it appears, by its having been announced in the published (and later) account of this machine, that, “the clock part of it may 203be contrived to play a great variety of Music,” (a suggestion wholly omitted in Mr. Rittenhouse’s original communication, made to the Rev. Mr. Barton,) that the philosophic Artist had been afterwards induced, in one particular at least, “to comply with the prevailing taste.”^[140] But this may be readily accounted for: our artist had previously made some extremely curious and beautiful Time-pieces, to each of which was attached the mechanism of a Musical Clock, in addition to a limited Planetarium, in miniature. These were in the hands of gentlemen of respectability and taste:^[141] and they were much and generally admired, 204as well for the great ingenuity displayed by the constructor, in these combined and pleasing operations of his machinery, as for the superior accuracy and beauty of the workmanship; qualities eminently conspicuous in all his mechanical productions.

It appears, that when Mr. Rittenhouse sent the foregoing description of his projected Orrery to Mr. Barton—that is to say, on the 27th of March, 1767^[142]—the 205“foundation” of it was “laid.” But, notwithstanding his earnest wishes prompted him to the utmost diligence, in his exertions to finish it, many circumstances concurred to retard its completion. The magnitude of the undertaking—the multiplicity of the work—and, perhaps, the difficulty of sometimes readily procuring, even from Philadelphia, the necessary materials,—all conspired, to prevent as early a completion of the machinery as he had anticipated: and, added to these causes of unavoidable delay, was the yet unabandoned pursuit of his professional business.

The Orrery was, nevertheless, then his favourite object. On the 18th of June, 1767, he wrote to Mr. Barton, thus—“I hope you will persuade your Pequea friends to stay for the clocks, till harvest is over; and then, I think, I may venture to promise them, for ready money: but, at this time, one part of the Orrery is in such forwardness, that I am not willing to lay it by till it is done. I hope it will far exceed the description I gave you of it. To-morrow morning I am to set off for Reading, at the request of the Commissioners of Berks county, who wrote to me about their town-clock. They had employed a ... to make it, who, it seems, is not able to go through with 206it: if I should undertake to finish it, this will likewise retard the great work.”

Amidst the more important philosophical pursuits which engaged Mr. Rittenhouse’s attention before his removal to Philadelphia, as well as after he fixed his residence in that city, he now and then relaxed the energy of his mind from its employment in laborious investigations, by bestowing a portion of his time on minor objects in physical science; and indeed, sometimes, even on little matters of ingenuity, curiosity and amusement. As instances of this, he addressed to the Rev. Mr. Barton the letter under the date of the 20th of July, 1768, which will be found in the Appendix; and also another, dated the 4th of February, 1770, to which there is the following postscript:

“I have,” says he, “seen a little curiosity, with which you would be pleased; I mean the glass described by Dr. Franklin, wherein water may be kept in a boiling state, by the heat of the hand alone, and that for hours together. The first time I shall be in Lancaster, where I hope to be next June, I expect to prevail on you to accompany me to the Glass-house,^[143] where we may have some of them made, as 207well as some other things I want.”—A description of this instrument, then usually called Dr. Franklin’s Pulse-Glass,^[144] by means of which water may be made to boil, in vacuo, by the heat of the human hand, was communicated by Mr. Rittenhouse to Mr. Barton in a subsequent letter.