Front matter (continued 3)

FOOTNOTES:

A NEW CRATER IN THE MOON.

Dr. Klein, a German astronomer, has recently called the attention of astronomers to a lunar crater some three miles wide, which had not before been observed, and which, he feels sure, was not in existence two years ago. Astronomers have long since given up all hope of tracing either the signs of actual life upon the moon or traces of the past existence of living creatures there. But there are still among them those who believe that by sedulous and careful scrutiny processes of material change may be recognised in that seemingly inert mass. In reality, perhaps, the wonder rather is that signs of change should not be often recognised, than that from time to time a new crater should appear or the walls of old craters fall in. The moon's surface is exposed to variations of temperature compared with which those affecting the surface of our earth are altogether trifling. It is true there is no summer or winter in the moon. Sir W. Herschel has spoken of the lunar seasons as though they resembled our own, but in reality they are very different. The sun's midday height at any lunar station is only about three degrees greater in summer than in winter; whereas our summer sun is 47° higher in the sky at noon than our winter sun. In fact, a midsummer's day on the moon does not differ more from a midwinter's day, as far as the sun's actual path on the sky is concerned, than with us the 17th of March differs from the 25th, or the 19th of September from the 27th. It is the change from day to night which chiefly affects the moon's surface. In the lunar year of seasons, lasting 346-2/3 of our days, there are only 11¾ lunar days, each lasting 29¾ of ours. Thus day lasts more than a fortnight, and is followed by a night of equal length. Nor is this all. There is neither air nor moisture to produce such effects as are produced by our air and the moisture it contains in mitigating the heat of day and the cold of night. Under the sun's rays the moon's surface becomes hotter and hotter as the long lunar day proceeds, until at last its heat exceeds that of boiling water. But so soon as the sun has set the heat thus received is rapidly radiated away into space (no screen of moisture-laden air checking its escape), and long before lunar midnight a cold exists compared with which the bitterest weather ever experienced by Arctic voyagers would be oppressively hot. These are not merely theoretical conclusions, though even as such they could be thoroughly relied upon. The moon's heat has been measured by the present Lord Rosse (using his father's splendid six-feet mirror). He separated the heat which the moon simply reflects to us from that which her heated surface itself gives out (or, technically, he separated the reflected from the radiated heat), by using a glass screen which allowed the former heat to pass while it intercepted the latter. He thus found that about six-sevenths of the heat we receive from the moon is due to the heating of her own substance. From the entire series of observations it appeared that the change of temperature during the entire lunar day—that is, from near midnight to near midday on the moon—amounts to fully 500° Fahrenheit. If we assume that the cold at lunar midnight corresponds with about 250° below zero (the greatest cold experienced in Arctic travelling has never exceeded 140° below zero), it would follow that the midday heat is considerably greater than that of boiling water on the earth at the sea-level. But the range of change is not a matter of speculation. It certainly amounts to about 500°, and in whatever way we distribute it, we must admit, first, that no such life as we are familiar with could possibly exist on the moon; and, secondly, that the moon's crust must possess a life of its own, so to speak, expanding and contracting unceasingly and energetically. Professor Newcomb, by the way, in his fine work on Popular Astronomy, rejects the idea that the expansions and contractions due to these great changes of temperature can cause any disintegration at the present time. There might, he says, be bodies so friable that they would crumble, 'but whatever crumbling might thus be caused would soon be done with, and then no further change would occur.' For my own part, I cannot consider that such a surface as the moon at present possesses can undergo these continual expansions and contractions without slow disintegration. It seems to me also extremely probable that from time to time the overthrow of great masses, the breaking up of arched crater-floors, and other sudden changes discernible from the earth, might be expected to occur. Professor Newcomb has, I conceive, omitted to consider the enormous volumetric expansion as distinguished from mere lateral extension, resulting from the heating of the moon's crust to considerable depths. On a very moderate computation, the surface of the central region of the full moon must at that time rise above its mean position to such a degree that hundreds, if not thousands, of cubic miles of the moon's volume lie above the mean position of the surface there. At new moon—that is, at lunar midnight for the same region—the same enormous quantity of matter is correspondingly depressed. And though the actual range in vertical height at any given point may be small, we cannot doubt that the total effect produced by these constant oscillations is considerable. Years or centuries may pass without any great or sudden change, but from time to time such catastrophes must surely occur. I believe that all the cases of supposed change in the moon, if all were regarded as proved, could be thus fully accounted for without any occasion to assume the action of volcanic forces properly so called.

Before considering the evidence for the new lunar volcano to which Dr. Klein has recently called the attention of astronomers, it may be well briefly to describe the condition of the moon's surface.

This surface, which is equal in extent to about that of the American Continent, or to Europe and Africa together (without their islands), is divided into two chief portions—the higher levels, which are in the main of lighter tint, and the lower levels, which are, almost without exception, dark. It may be remarked in passing that very erroneous ideas are commonly entertained respecting the moon's general colour. The moon is very far from being white, as many suppose. On the contrary, she is far more nearly black than white. It has been well remarked by Tyndall that if the moon were covered with black velvet (14,600,000 square miles of that material would be required for the purpose), she would still appear white to us, for we should see her disc projected on the blackness of star-strewn space. The actual tint of the moon as a whole is nearly the same as that of gray weathered sandstone. The brightest parts, however, are much whiter; Zöllner infers from his photometric experiments that they can be compared with the whitest of terrestrial substances. On the other hand, the darkest parts of the moon are probably far darker than porphyry, even if they are not so dark that on earth we should call them black. The fact that the low-lying parts of the moon are much darker than the higher regions is full of meaning, though hitherto its significance does not seem to have been much noticed. Either we must assume that these lower regions, the so-called seas (certainly now dry), are old sea bottoms, and owe their darkness to the quality of the matter deposited there in remote ages, or else we must suppose that the matter which last remained fluid when the moon's surface was consolidating was of darker material than the rest. For such matter would occupy the lowest lunar regions. There is here room for a very profitable study of the moon's aspect by geologists. I doubt not that, however different the general past history of our earth may have been from the moon's, terrestrial regions exist where the characteristic features of the moon's surface are more or less closely illustrated. On the American continent, for example, there are peculiarities of geological formation which seem to correspond closely with some of the features of the lunar globe, presently to be noticed; and it seems to me not improbable that geologists might find in the study of certain regions in North America the means of interpreting the difference of tint between higher and lower levels on the moon. If so, light would probably be thrown on very difficult questions relating to the remote past, not only of the moon, but of our own earth.

The lunar feature which comes next in importance to the difference of tint between the so-called 'seas' and the higher lands is the existence of remarkable series of radiating streaks extending from certain important craters—centres probably of past disturbance. It is impossible to contemplate the disc of the full moon, as seen with a powerful telescope, without feeling that these systems of rays must have resulted from the operation of forces of the most stupendous nature, though as yet their true meaning is hid from us. They would be marvellous phenomena, even if they were not so mysterious—marvellous in their enormous extension, their singular brightness, and their manner of traversing 'seas,' craters, and mountain-ranges indifferently. But their chief marvel resides in the mysterious manner of their appearance as the moon approaches her full illumination. Other lunar features are most clearly recognised when the moon is not full, for then the shadows which afford our only means of estimating the height of lunar irregularities are clearly seen along the border between the bright and dark parts of her face, and we have only to wait until this border passes over any object we wish to study to obtain satisfactory evidence of its nature. It is quite otherwise with the rays. The regions occupied by these radiating streaks are neither raised nor depressed in such sort as either to throw shadows or to lie in shadow when surrounding regions are in sunlight. But when the moon approaches her full illumination, the radiating regions come into view, as bright streaks—bright even on the light-tinted lunar uplands. A mighty system of rays can be seen extending from the great crater Tycho in all directions. Other systems, scarcely less wonderful, extend from the battlemented crater, Copernicus, the brilliant Aristarchus, and the solitary Kepler. One ray from Tycho can be traced round nearly an entire hemisphere of the moon's surface. It is specially noteworthy of this great ray that, where it crosses the lunar Sea of Serenity, that great plain seems to be divided as by a sort of ridge line, the slope of the plain from either side of the ray's track being clearly discernible when the moon is near her first quarter.

What are these mysterious ray systems? How are we to explain the circumstance that though only the most tremendous forces seem competent to account for bands such as these, many miles broad and many hundreds of miles in length, there are yet none of the usual signs of the action of volcanic forces? If mighty rifts had been formed in the moon's crust by the outbursting action of a hot nucleus, or through the contraction of the crust on an unyielding nucleus (for the effect would be the same in either case), we should scarcely expect to find that after such rifts had formed no signs of any difference of level would appear. If lava flowed out all along the rift, one would imagine that it would form a long dyke which would throw an obvious shadow, except under full solar illumination. If the rift were not filled with lava, the bottom of the rift would certainly remain in shadow long after the surrounding region was illuminated. That lava should exactly fill the rift along its entire length seems incredible. This might happen by a strange chance in the case of a single rift, but not with all the rifts of a radiating system, still less with all the rifts of all the radiating systems. Yet I believe that neither astronomers nor geologists can form any other opinion respecting these mysterious ray-systems than that they were caused by what Humboldt (speaking of the earth) calls the reaction of the interior on the crust. Nasmyth has admirably indicated their appearance, or rather their radiating form, by filling a globular glass shell with water, hermetically closed, and then freezing the water. The expansion of the water bursts the glass shell, and the lines of fracture are found to extend in a series of rays from the part of the shell which first gave way. But this experiment of itself does not explain the mystery of the lunar rays. Accepting the theory that the moon's crust yielded in some such way, we have still to explain how the rifts which were thus formed came to be covered over with matter lying nearly at the same level as the surrounding surface. It appears to me that the only available way of explaining this is somewhat as follows. First, from the way in which the streaks are covered like the surrounding region with craters, we may conclude that the streaks are older than any except the largest craters; from the great extension of many of them, we may safely infer that the lunar crust possessed a large measure of plasticity when they were formed (for otherwise it would have yielded over a smaller area). It was, therefore, probably still hot during the era (which may have lasted millions of years) to which the formation of the rifts belonged: accordingly the lava which flowed out through the rifts remained liquid for a considerable time, and was thus able to spread widely on either side of the rift, forming a broad band of lava-covered surface, instead of a steep and narrow dyke. This seems not only to account for the most striking peculiarity of the bands, but to accord well with all that is known about them, and even to suggest explanations of some other lunar features which had appeared perplexing. I understand that in certain regions of North America there are lava-covered rifts large enough to form geographical features, and, therefore, fairly comparable with the lunar radiating streaks. But as yet American geologists have not presented in an accessible form a description of the peculiar features of the American continent; in fact, it may be doubted whether as yet the materials for such a description exist.

The mountain-ranges of the moon do not differ to any marked degree from those of our own earth. They are few in number; in fact, mountain-ranges form a less important feature of lunar than of terrestrial geography. On the other hand, the lunar ring-mountains and craters far exceed those of our earth in size and importance. The large craters may, in fact, be regarded as characteristic features of lunar scenery. There are several craters exceeding 100 miles in diameter. It is strange to consider that though the ringed wall surrounding some of these larger craters exceeds 10,000 feet in height, no trace of the highest peaks of such a wall would be visible from the middle of the enclosed plain. Conversely, an observer standing on one of the highest peaks beside one of these great craters, would not see half the floor of the crater, while more than half the horizon line around him would belong to the enclosed plain, and would appear as level as the horizon seen from a height overlooking a great prairie. These ringed plains and larger craters seem to belong to the third great era of the moon's history. The bright high regions and dark low levels called seas must have been formed while the greater part of the crust was intensely hot. The contraction of the cooling crust on the nucleus, which cooled far less slowly, led to the formation of the great ray systems. But though such systems extend from great craters, these craters themselves probably attained their present form far later. The crust having in great part cooled, the nucleus began in turn to shrink more quickly than the crust, having more heat to part with. Thus the crust, closing in upon the shrinking nucleus, formed the corrugations and wrinkles which can be seen under telescopic scrutiny in nearly every part of the visible lunar surface. The process was accompanied necessarily by the development of great heat—the thermal equivalent of the mechanical process of contraction. Mallet has shown that the process of contraction at present occurring in the earth's crust gives rise to the greater part of the heat to which volcanic phenomena are due. If this is so in the earth's case at present, how tremendous must have been the heat evolved by the far more rapid contraction of the moon's mass in the remote era we are considering, when probably her heat passed into space unchecked by the action of a dense moisture-laden atmosphere! We can well understand that enormous volumes of heated gas would be formed—including steam, for there is good reason to believe that water is present in large quantities in the moon's interior. The imprisoned gas would find an outlet at points of least resistance, the centres, namely, of the great radiating systems of streaks. These centres would certainly be regions of outlet. But they would not be sufficient. We can understand then why every ray system extends from a great crater, though that crater was really formed after the system of radiating streaks; and we can equally understand why these central craters are not the only or even the chief of the great craters in the moon. Here again I would suggest that possibly the careful study of American geology might disclose features illustrating the great lunar craters.

When we pass to the smaller craters, ranging in diameter from seven or eight miles to less than a quarter of a mile, even if there be not some far smaller and beyond the range of the most powerful telescopes man can construct, we find ourselves among objects resembling those with which the study of our own earth has rendered us familiar. When Sartorius's map of Etna and the surrounding region was first seen at the Geological Society's rooms, many supposed that it represented lunar features. The Vesuvian volcanic region, again, is presented side by side with a lunar region of similar extent in Nasmyth's fine treatise on the moon, and the resemblance is very close. Considering the part which water plays in producing terrestrial volcanic phenomena, it may reasonably be doubted whether there is in reality so close a resemblance as a superficial comparison (and we can make no other) would suggest. There are those, indeed, who believe that some of the multitudinous small craters of the moon have had their origin in the downfall of meteoric masses on her once plastic surface; and strange though the thought may seem, there would be considerable difficulty in showing how the surface of the moon could have remained without traces of the meteoric downfall to which during myriads of centuries she was exposed undefended by that atmospheric shield which protects our earth from millions of meteors yearly falling upon her. We could only attribute the smallest lunar craters, however, to this cause. It may be noticed in passing that Professor Newcomb, apparently referring to this suggestion, which some had thought too fanciful to be seriously advanced, says that 'the figures of these inequalities (the small craters) can be closely imitated by throwing pebbles upon the surface of some smooth plastic mass, as mud or mortar.' Craters, however, larger than a mile or so in diameter, and many also of smaller dimensions, must be regarded as due to the same process of contraction which produced the great craters, but as belonging to an era when this process went on less actively. In like manner another feature of the moon's surface, the existence of narrow furrows called rilles, which sometimes extend to a considerable distance, passing across levels, intersecting crater walls, and reappearing beyond mountain-ranges as though carried under like tunnels, must be regarded as due to the cracking of the crust thus slowly shrinking.

It is noteworthy that the signs of change which have been suspected during recent years belong to these smaller and probably more recent lunar formations. In November, 1866, Dr. Schmidt, chief of the Athens Observatory, announced that the crater Linné in the lunar Sea of Serenity was missing. To understand the importance of this announcement, let it simply be noted that the quantity of matter necessary to fill that crater up would be at least equal to that which would be required to form a mountain covering the whole area of London to a height of two miles! The crater was described by former lunar observers as at least five miles in diameter and very deep. It is not now actually missing, as Schmidt supposed, but it is certainly no longer deep. It is, in fact, exceedingly shallow. Sir J. Herschel's opinion was that the crater had been filled up from beneath by an effusion of viscous lava, which, overflowing the rim on all sides, poured down the outer slope so as to efface its ruggedness and convert it into a gradual declivity casting no stray shadows. But the stupendous nature of the disturbing forces necessary to produce such an overflow of molten matter has led most astronomers to adopt in preference the theory that the wall surrounding the crater has been overthrown, either in consequence solely of the processes of contraction and expansion described above, or from the reinforcement of their action by the effects due to sublunarian energies. Some consider that the descriptions of the crater by Mädler and Lohrmann (which slightly differ) were erroneous, and that there has been no real change. Others deny that any change has occurred, on the ground that Linné varies in aspect according to the manner of its illumination. This I perceive is Professor Newcomb's explanation, who considers such variations 'sufficient to account for the supposed change.' But since the time of Schmidt's announcement Linné has several times been observed under nearly the same conditions as by Mädler and Lohrmann, as the great shadows formerly seen in its interior have not reappeared. There seems to be great reason for believing that a change has really occurred there.

The discovery announced by Dr. Klein is of a different nature. Near the middle of the visible half of the moon there is a well-known though small crater called Hyginus, the neighbourhood of which has been often and carefully examined. While examining this part of the moon's surface with an excellent 5-1/2in. telescope, in May, 1877, Dr. Klein observed a small crater full of shadow, and apparently nearly three miles in diameter. It formed a conspicuous object on the Sea of Vapours. Having frequently observed this region during the last few years, he felt certain that no such crater existed there in 1876. He communicated his discovery to Dr. Schmidt, who stated, in reply, that in all the numerous drawings he had made of this lunar region no such crater was indicated. It is not shown in the great chart by Beer and Mädler, or in Lohrmann's map. Further observation showed that the crater is a deep, conical opening in the moon's surface. Soon after the sun has risen at that part of the moon, and, as later observations confirm, shortly before sunset there, the opening is entirely in shadow, and appears black. But when the sun is rather higher it appears grey, and with a yet higher sun it can no longer be distinguished. It can, however, be seen when the sun is very high on that part of the moon, appearing then somewhat brighter than the surrounding region, a circumstance which does not hitherto seem to have been noticed by either Klein or Schmidt.

The moon's surface has been so long and so carefully studied, that it is almost impossible to understand how such a crater as now certainly exists in the Sea of Vapours near Hyginus could have escaped detection. Craters of the kind exist, indeed, in hundreds on the moon's surface. But many astronomers have given years of their life to the study of such objects; and the centre of the moon's disc, for reasons which astronomers will understand, has been studied with exceptional care. It seems so unlikely that a deep crater three miles in diameter could escape recognition, that some astronomers have not hesitated to regard the newly-detected crater as certainly a new formation. For my own part, though it seems almost impossible to explain how such a crater could have remained so long unnoticed, I can regard the evidence of change as amounting only to extreme probability so far as it depends on the result of past telescopic scrutiny of the moon.

Admitting that a change had occurred, it would not follow that it had been produced by volcanic forces. It seems far more likely that a floor originally covering the conical hole now existing in the Sea of Vapours has given way at last under the effect of long-continued processes of expansion and contraction, which would operate with special energy over a region, like the Sea of Vapours, near the moon's equator.

But there remains to be mentioned a form of evidence respecting lunar features which could not be effectively applied to the case of the crater Linné, because the moon had only been subject to the necessary method of examination during a few years before that crater was missed. I refer to lunar photography. Many objects less than two miles in diameter are shown in the best photographs of our satellite by Rutherfurd, De la Rue, Ellery, and Draper; and as the moon has been photographed in every phase, some among the views might fairly be expected to show Klein's crater if it really existed before 1877. I do not find that in any lunar photographs the crater is shown as a black or dark gray spot. But in Rutherfurd's splendid photograph of the moon on March 6, 1865 (when the moon was about nine days five hours old), the place of Klein's crater is occupied by a small spot lighter than the surrounding 'sea.' This is the usual appearance of a small crater under a high sun; and though it may indicate only the existence of a flat crater floor in 1865 where now a great conical hole exists, it throws some degree of doubt on the occurrence of any change at all there. The case strongly suggests the necessity for continuing the work of lunar photography, which seems of late years to have flagged. Photographs of the moon should be taken in every aspect and in every stage of her librational swayings. Possessing such a series, we should be able to decide at once whether any newly-recognised crater was in reality a new formation or not.

THE NOVEMBER METEORS.

During November 13 and 14 the earth is passing through the region along which lies the course of the family of meteors called the Leonides, sometimes familiarly known as the November meteors. When at this time of the year the meteor region thus traversed by the earth is densely strewn with meteors, there occurs a display of falling stars, one of the most beautiful, and, rightly understood, one of the most remarkable of all celestial phenomena. Of old, indeed, when it was supposed that these meteors were purely meteorological phenomena, they were not thought specially interesting objects. They were held by some as mere weather-portents. It was only when a storm of wind was approaching, vento impendente, according to Virgil, that a shower of meteors was to be seen. Gross ignorance, indeed, has given to showers of falling stars an interest surpassing even that which has become attached to them through the discoveries of modern science, for they have been regarded as portending the end of the world. The shower of November 13, 1833, which was seen in great splendour in America, frightened the negroes of the Southern States nearly out of their wits. A planter of South Carolina relates that he was awakened by shrieks of horror and cries for mercy from 600 or 700 negroes. When he went out to see what was the matter, he found the negroes prostrate on the ground, 'some speechless, some with bitterest cries imploring God to spare the world and them.' There is, however, a grandeur in the interpretation placed by modern science upon these beautiful displays which dwarfs into littleness even such ideas as have been suggested by the terrors of superstition. We perceive that meteors are not mere terrestrial phenomena, nor of brief existence. They speak to us of domains in space compared with which the volume of our earth—nay, even the volume of the sun himself—is a mere point: of time-intervals compared with which the millions of years spoken of by geologists appear but as mere seconds.

The special meteor family whose track the earth crosses on November 13-14 forms a mighty ellipse round the sun, extending more than 19 times farther from him than the track of our earth, which yet, as we know, lies more than 92,000,000 miles from the sun. Along this tremendous orbit the meteors speed with planetary but varying velocity, crossing the track of our earth with a velocity exceeding by more than a third her own swift motion of about 19 miles in every second of time. Coming down somewhat aslant, but otherwise meeting the earth almost full tilt, the meteors rush into our air at the rate of more than 40 miles per second. They are so intensely heated as they rush through it that they are turned into the form of vapour, insomuch that we never make acquaintance with the members of this particular meteoric family in the solid form. In this respect they resemble the greater number of our meteoric visitants. It is, indeed, a somewhat fortunate circumstance for us that this is so, for if Professor Newton, of Yale College (United States), is right in estimating the total number of meteors, large and small, which the earth encounters per annum at 400,000,000, it would be rather a serious matter if all or most of these bodies were not warded off. The least of them, even though a mere grain perhaps in weight, would yet, arriving with planetary velocity exceeding a hundredfold or more the velocity of a cannon-ball, prove an awkward missile if it struck man or animal. But the air effectually saves us from all save a few fire-balls which are large enough to remain in great part solid until they actually strike the earth itself.

The importance of the meteors in the planetary system will be recognised when we remember that the November group alone extends along its oval course in one complete system of meteors for a length of more than 1,700 millions of miles, with an average thickness of about a million miles (determined by noting the average time occupied by the earth in passing through the system on November 13-14), and an unknown cross breadth which probably does not fall short of three or four millions of miles. Other systems are, no doubt, far more important, for it has been found that meteors follow in the track of comets. Now the November meteors follow in the track of a comet (Tempel's comet of 1866), which was so small when last favourably placed for observation that it escaped detection by the naked eye. If so small a comet as this is followed by so large a meteoric system, in which also meteors are strewn so richly that during the passage of the earth through it, tens of thousands of meteors have been counted, how vast must be the numbers and how large probably the individual bodies following in the track of such splendid comets as Newton's, Donati's (1858), the comets of 1811, 1847, 1861, and others! For it should be remembered that we become cognisant of the existence of a meteoric system only when the earth threads its way through one, when those which she encounters may become visible as falling stars if it so chances that she encounters them on the dark or night half of her surface. But the earth is far smaller compared with a system like the November meteor-flight than a rifle-ball compared with the largest flight of birds ever yet seen. Such a ball fired into a very dense and widely extending flock of birds might encounter here and there along its course some five or six birds—not one in 10,000, perhaps, of the entire flight; and if the flock continued flying with unchanging course, a hundred rifle balls might be fired through it without seemingly reducing its numbers. Our earth has passed hundreds of times through the November meteor system, yet its meteoric wealth has scarcely been reduced at all, so exceedingly minute is the track of the earth through the meteor system compared with the extension of the system itself. The region through which the earth has passed is less than a billionth part of the entire region occupied by the system. But the November system is but one among several hundreds through which the earth passes—in other words, the systems which chance to be traversed by that mere thread-like ring in space traversed each year by the earth, are not a millionth, not a billionth, of the total number of such systems. It will be conceived, therefore, that the total amount of meteoric matter, travelling on orbits of all degrees of eccentricity and extension from the sun and inclined at all angles to the general plane of the solar system, must be enormously great. The idea once advanced by an eminent astronomer that the total quantity of unattached matter, so to speak, existing within the solar domain must be estimated rather by pounds than by tons is now altogether exploded. It would be truer to say that the totality of matter thus freely travelling around the sun must be estimated by billions of tons rather than by millions.

Whether it is likely that there will be a display of meteors to-night (or, rather, to-morrow morning), is a question to which most astronomers would be disposed, we believe, to reply definitely in the negative. The display of November 13-14, 1866, was very brilliant; that of 1867 (best seen in the United States) was almost equally so; but successive showers steadily diminished. In other words, the part of the system crossed by the earth in 1866 and 1867 was very rich, but the part which she crossed afterwards (the rich part having passed far on towards the remote aphelion of the system outside the orbit of Uranus) was less rich. For the last few years very few November meteors have been seen, though the few stragglers which have been seen, and have been identified as belonging to the family by their paths athwart the star-depths, have been almost as interesting to astronomers as the showers of such bodies seen in 1799, 1833, 1866, and 1867. But it is not altogether impossible that in the small hours 'ayont the twal' to-morrow morning a shower of meteors may be seen. For Schiaparelli (the Italian astronomer who first started the ideas which led when properly followed up to the discovery of the relations existing between meteors and comets) asserts that it has happened before now that the November meteors have appeared in great numbers in years lying midway between the times of maximum display. These times are separated on the average by about 33¼ years. Thus, in 1799, there was a great display of November meteors, a shower rendered specially celebrated by Humboldt's description. In 1833 there was another, the display which so terrified the negroes of South Carolina, but more interesting scientifically as described by Arago. In 1866 the shower again attained its maximum splendour, though the display of 1867 was little inferior. It will not be till 1899 that another great shower of November meteors may be confidently looked for. But if Schiaparelli be right, it is quite possible that there may be a shower this year, due to some scattered flight of the November meteors which, delayed accidentally (through some special perturbation) many hundreds of years ago, has come in the course of ages to travel nearly half a circuit behind the richest part of the system, the 'gem of the meteor-ring,' as it has been poetically called. Even, however, though no display of November meteors should be seen, yet the recognition of even a few scattered stragglers would be exceedingly interesting to astronomers. A single meteor seen to-night which could be regarded as certainly belonging to the November system would suffice to show the possibility that a whole flight of the November meteors might travel at a similar distance behind the main body. It would be more easy, however, to identify two such meteors than one, six than two, and a score than half-a-dozen. The only way in which a meteor can be questioned, so to speak, respecting the family it belongs to, is by noting its path across the sky. If this path tends directly from the constellation Leo (however remote Leo may be from the part of the heavens traversed by the meteor), the chances are that the meteor is a Leonid, or one of the November family. If the path tends from that particular part of the constellation Leo (near the end of the curved blade of the so-called Sickle in Leo), the probability of the meteor being a Leonid is increased. If two or more meteors are seen to-morrow morning (after 12.30) which both tend from the Sickle in Leo, even though they seem to tend in opposite directions, the chances are yet greater that they are travelling in parallel paths along the track of the November meteors, but some 2,000 million miles behind the main body. Should the number mount up to a score or so, the conclusion would be, to all intents and purposes, certain; and the possible occurrence of even a shower of Leonids at a time midway between the customary maxima of the meteoric displays would be placed beyond question.

We must, however, admit that it seems less likely there will be anything like a display of Leonids to-night than that patient observers may be able to identify a few of these bodies, and thus—though by observations of a less attractive kind—to advance our knowledge of this interesting system. Far more likely is it that towards the end of the month there will be a display of meteors belonging to another and an entirely distinct family, a family scarcely less worthy to be called November meteors par excellence, but actually rejoicing in the classically unsatisfactory name of Andromeds.

EXPECTED METEOR SHOWER.

(From the Times of November 25, 1878.)

It is probable that during the next three nights some light may be thrown on one of the most perplexing yet most interesting of all the problems recently suggested to the study of astronomers. It is confidently expected that many of those November meteors called Andromeds will be seen on one or other of those nights, if not on all three. No meteor systems, not even the famous systems of August and November, are more remarkable than this singular family. To explain why astronomers regard the Andromeds with so much interest, it will be necessary to speak of an object which at first sight seems in no way connected with them—an object, in fact, which, so long as it was actually known to astronomers, was never supposed to be connected with any family of meteors—the celebrated lost comet called Biela's (or, by Frenchmen, Gambart's comet). In February, 1826, Biela discovered in the constellation Aries a comet which was found to be travelling in an oval path round the sun, in a period of about six years seven and a half months. Tracing its course backwards, astronomers found that it had been seen in 1772 by Montaigne, and observed for two or three weeks in that year by Messier, the great comet hunter. Nothing very remarkable was recognised regarding this comet in 1826, except the fact that its path nearly intersects that of our own earth; so that if ever the earth is to encounter a comet, here seemed to be the comet she had to fear. Great terror was, indeed, excited by the announcement that in 1832 the comet would cross the earth's track only four or five weeks before the earth came to the place of danger. But no harm happened. In that year, and again in 1839, the comet returned quietly enough, though in 1839 it was not observed, being so placed that it was lost in the splendour of the solar rays. In February, 1846, the comet was again seen, this being the third return since its discovery in 1826, or rather, since its recognition as a member of the solar system, the eleventh since it was first seen by Montaigne. At this time everything seemed to suggest that this comet, unless our earth at some future time should absorb it, would remain for a long time a steady member of the sun's comet family. But only a few days after its detection in February, 1846, the comet was found to have divided into two, which travelled side by side until both vanished from view with increasing distance. In 1852 the companion comets reappeared, and again both continued in view till their motion carried them beyond telescopic range. As the distance between the coupled comets had increased from about 160,000 miles in 1846 to about 1,250,000 miles in 1852, astronomers anticipated a most interesting series of observations at the successive returns of the double comet to the earth's neighbourhood. Unfortunately, in 1859 the comet's course carried it athwart a part of the sky illuminated by the sun's rays, so that astronomers could not then expect to see it. But in 1866 it was looked for hopefully. Its orbit had now been most carefully computed, and many observers, armed with excellent telescopes, were on the watch for it, with very accurate knowledge of the course along which it might be expected to travel, and even of its position from day to day and from hour to hour. But it was not seen. Nor, again, was it seen in 1872, when fresh computations had been made, and observations were extended over a wider range, to make sure, as was hopefully thought, that this time it should not escape recognition. Could it have come, asked Herschel in 1866—and in 1872 the same question might still more pertinently be asked—into contact or exceedingly close approach to some asteroid as yet undiscovered? or, peradventure, had it plunged into and got bewildered among the rings of meteorolites, which astronomers more than suspected?

Between 1866, when Sir John Herschel thus wrote, and 1872, when again Biela's comet was sought in vain, a series of strange discoveries had been made respecting meteors, which led astronomers to believe that, even though the missing comet might never again be seen as a comet, we might still learn something respecting its present condition. It had been noticed that the remarkable comet of 1862 (comet 11 of that year) crossed the earth's track near the place where she is on August 10-11, the time of the August meteors, called the Tears of St. Lawrence in old times, but now known as the Perseids, because they seem to radiate from the constellation Perseus. Later the idea occurred to Schiaparelli, an Italian astronomer, that the August meteors may travel along the path of that comet. He could not prove this, but he advanced very strong evidence in favour of the opinion, for he found that bodies travelling along the path of the comet of 1862 would seem to radiate from Perseus as they traversed the earth's atmosphere. It was as if a person suspected that a steam-cloud seen on a distant railway track belonged to a particular train, and, though unable actually to prove this, was yet able to show that, with the wind and weather then prevailing, that train, travelling at its customary rate, would leave a steam-cloud behind it precisely of the apparent length and position of the observed steam-cloud. This cloud might have the observed position though otherwise produced, yet the evidence would be thought strongly to favour the supposition that it came from the train in question. In like manner the August meteors might be travelling on any one of a great number of tracks intersecting the earth's orbit in the place occupied by the earth on August 10-11; yet it was at least a striking coincidence that a flight of meteors travelling in the orbit of the chief comet of 1862 would seem to radiate from the constellation Perseus, precisely as the August meteors do.

While astronomers were still discussing the ideas of Schiaparelli, Professor Newton of Yale College, in America, called their attention to the great display of November meteors which might be expected on November 13-14, 1866. The fine shower of that year was well observed, and the part—we may almost say the point—of the constellation Leo from which the meteors radiated was correctly determined. And now a strange thing happened. Those who believed in Schiaparelli's account of the August meteors supposed of necessity that the bodies forming that system travel in an orbit of enormous extent, for the comet of 1862 travels on a path extending much further from the sun than the path of Neptune. There was, therefore, nothing to prevent them from believing that the Leonides travel in a track carrying them far away from the sun. The recurrence of great displays of these meteors at intervals of about 33 years might be readily explained on such an assumption, for if the Leonides have a period of about 33 years, their path must extend far beyond the path of Uranus. But hitherto astronomers had not been ready to admit such an explanation of the periodic recurrence of great displays of the November meteors. They preferred theories (for several were available) which accounted for the 33-year period, while assigning to the Leonides paths of much less extent. Now that the idea of vast meteoric orbits had been fairly broached, some astronomers thought it might at least be worth while to calculate the path of the November meteors on the assumption that their true period is about 33¼ years. This was perfectly easy, because the period of a body travelling round the sun determines the velocity at any given distance from the sun, and knowing thus (at least, on this assumption) the true velocity of the Leonides as they rush into our air, while their apparent path is known, their true course is as readily determined as the true course of the wind can be determined by a seaman from the apparent direction and velocity with which it reaches his ship. When the path of the November meteors had been determined (on the assumption mentioned), it was found to be identical with the path of a comet which had only been discovered a few months before-the comet called Tempel's. That a comet which is invisible to the naked eye should have been discovered in the very year when first astronomers made exact observations of the meteors which travel in its track—for it will presently be seen that the assumption above mentioned was a just one—cannot but be regarded as a very singular coincidence. It was a most fortunate coincidence for astronomers, since there can be but little doubt that but for it Schiaparelli's theory would very soon have been forgotten. As that theory was itself suggested by the fortuitous recognition of another comet (only visible at intervals of more than a century) at a time when attention had been specially directed to the August meteors, it may fairly be said that the theory which now associates meteors and comets in the most unmistakable manner was suggested by one accident and confirmed by another. Albeit such accidents happen only to the zealous student of nature's secrets. We shall presently see that the fortunate detection of Tempel's comet in 1866 was not the last of the series of coincidences by which the theory of meteors was established.

Although the evidence favouring Schiaparelli's theory was now strong, yet it was well that at this stage still more convincing evidence was forthcoming. The date of the November display has changed since the Leonides were first recognised, in such sort as to show that the position of their path has changed. The change is due to the disturbing attractions of the planets. It occurred to our great astronomer Adams, discoverer with Leverrier of distant Neptune, to inquire whether the observed change accorded with the calculated effects of planetary attraction, if the Leonides are supposed to travel in any of the smaller paths suggested by astronomers, or could be explained only by the assumption that the meteors travel on the widely-extending path corresponding to the 33¼ years period. The problem was worthy of his powers—in other words, it was a problem of exceeding difficulty. By solving it, Adams made that certain which Schiaparelli and his followers had merely assumed. He showed beyond all possibility of doubt or question that of all the paths by which the periodic meteoric displays could be accounted for, the wide path carrying the November meteors far beyond the track of Uranus was the only one which accorded with the observed effects of planetary perturbation.

It was in the confidence resulting from this masterly achievement that in 1872 some astronomers (among them Professor Alex. Herschel, one of Sir J. Herschel's sons) announced the probable occurrence of a display of meteors when the earth crossed the track of Biela's missing comet. An occurrence of this sort was alone wanting to complete the evidence for the meteoric theory. It had been found that the August Perseids move as if they followed in the track of a known comet; the path of the November Leonides had been shown to be identical with that of another comet; if astronomers could predict the appearance of meteors at the time when the earth should pass through the track of a known comet, even those who could not appreciate the force of the mathematical evidence for the new theory would be convinced by the meteoric display. Possibly such observers would have been satisfied with a meteor shower which would not have contented astronomers. The display must have special characteristics to satisfy scientific observers. The path of a body following Biela's comet being known, and its exact rate of motion, the direction in which it must enter our earth's atmosphere (if at all) is determined. Calculation showed this direction to be such that every meteor would appear to travel directly from the constellation Andromeda,—from a point near the feet of the Chained Lady. A meteor might appear in any part of the sky, but its course must be directed from that point, otherwise it could not possibly be travelling in the track of Biela's comet.

The event corresponded exactly with the anticipations of astronomers. On the evening of November 27, 1872, many thousands of small meteors were seen. In England between 40,000 and 50,000 were counted. In Italy the meteors were so numerous that at one time there seemed to be a cloud of light around the region near the feet of Andromeda whence all the meteor-tracks seemed to radiate. The meteors were unmistakably travelling on the track of Biela's comet. They overtook the earth on a path slanting downwards somewhat from the north—precisely in the direction in which Biela's comet would itself have descended upon the earth if at any time the earth had chanced to reach the part of her path crossed by the comet's when the comet was passing that way.

Strangely enough, a German astronomer, Klinkerfues, seems to have regarded the meteoric display of November 27, 1872, as an actual visit from Biela's comet. He telegraphed to Pogson, Government Astronomer at Madras, 'Biela touched earth on November 27, look out for it near Theta Centauri;' which, being interpreted, means, Biela's comet then grazed the earth, coming from the feet of Andromeda, look for it where it is travelling onwards in the opposite direction—that is towards the shoulder of the Centaur. As Biela's comet had in reality passed that way twelve weeks earlier, the instructions of Klinkerfues were somewhat wide of the mark. However, Pogson followed them, and near the spot indicated he saw two faint cloud-like objects, slowly moving athwart the heavens. These he supposed to be the two comets into which the missing comet had divided. It so happens, strangely enough, that these objects, though moving parallel to the track of the missing comets, were neither those comets themselves, nor the meteor flight through which the earth had passed a few hours before. They were probably somewhat richer meteor clouds, fragments (like the cloud through which our earth had passed) of this most mysterious of all known comets.

To-night, or perhaps to-morrow or next night (for the position of the meteor flights is not certainly known) we shall probably see meteors travelling in advance of the main body. For the earth passes during the next three days across the orbit of Biela's comet, about as far in front of the head as she passed behind the head in 1872. Now, there is no known reason for supposing (on à priori grounds) that meteors get strewn behind a comet's nucleus more readily than in front of it. The disturbing forces which would tend to delay some meteoric attendants would be balanced by forces which would tend to hasten others. As a matter of fact it would seem that the meteor flights which follow a comet's nucleus are commonly denser than those which precede the nucleus. Yet in 1865 many thousands of Leonides were seen which were in advance of the main body forming the comet of 1866. In 1859, 1860, and 1861, many Perseids were seen, which were in advance of the comet of 1862. So that we might fairly expect to see a great number of Andromeds to-night (or on the following nights) even if we had none but the probabilities thus suggested to guide us. But since many were seen on November 27 last, when the head of the comet, now some four months' journey from us, was a whole year's journey further away, it seems probable that on the present occasion a display well worth observing will be seen should fine weather prevail. It will be specially interesting to astronomers, as showing how meteors are strewn in front of a comet. How meteors are strewn behind a comet we already know tolerably well from observations made on the Perseids since 1862 and on the Leonides since 1865.

COLD WINTERS.

During the cold weather of last December (1878) we heard much about old-fashioned winters. It was generally assumed that some thirty or forty years ago the winters were colder than they now are. Some began to speculate on the probability that we may be about to have a cycle of cold winters, continuing perhaps for thirty or forty years, as the cycle of mild winters is commonly supposed to have done. If any doubts were expressed as to the greater severity of winter weather thirty or forty years ago, evidence was forthcoming to show that at that time our smaller rivers were commonly frozen over during the winter, and the larger rivers always encumbered with masses of ice, and not unfrequently frozen from source to estuary. Skating was spoken of as a half-forgotten pastime in these days, as compared with what it was when the seniors of our time were lads. Nor were dismal stories wanting of villages snowed up for months, of men and women who had been lost amid snowdrifts, and of other troubles such as we now associate rather with Siberian than with British winters.

Turning over recently the volume of the 'Penny Magazine' for the year 1837, I came across a passage which shows that these ideas about winter weather forty years ago were entertained forty years ago about winter weather eighty or ninety years ago. It occurs in an article on the 'Peculiarities of the Climate of Canada and the United States.' Discussing the theory whether the clearing away of forests has any influence in mitigating the severity of winter weather, the writer of the article says, 'Many persons assert, and I believe with some degree of accuracy, that the seasons in Europe, and in our own island particularly, have undergone a remarkable change within the memory of many persons now living; and if such really be the case, how few attempts have been made to account for this change, since no great natural phenomenon, like that of clearing away millions of acres of forest timber, and thereby exposing the cold and moist soil to the action of the sun's rays, has recently taken place here; so that if the climate of Great Britain has actually undergone a change, the cause, whatever that may be, must be of a different nature from that generally supposed to affect the climate of North America.' It must be explained that, though in this passage the writer does not speak of a diminution in the severity of the winters, it is a change of that sort that he is really referring to. He had said, a few lines before, that 'some of the older inhabitants of North America will declare to you that the winters are much less severe "now" than they were forty or fifty years ago,' and in the passage quoted he is discussing the possibility of a similar change in Europe, where, however, as he points out, the cause assigned to the supposed change in America has certainly no existence. Since 1830, by the way, the theory has been advanced that the supposed mildness of recent winters may have been caused by the large increase in the consumption of coal, owing to the use of steam machinery, gas for lighting purposes, and so forth.

I believe it will be found on careful inquiry that the change for which forty years ago men sought a cause in vain, and for which at present they assign a perfectly inadequate cause, has had no real existence. The study of meteorological records gives no valid support to the theory of change. Nor is it difficult to understand how the idea that there has been a change has arisen from the changed conditions under which men in middle life, as compared with children, observe or feel the effects of milder weather. A child gives no heed to mild winters. They pass, like ordinary spring or autumn days, unnoted and unremembered. But a bitter winter, or even a spell of bitter weather such as is felt almost every year, is remembered. Even though it lasts but for a short time, it produces as much effect on the childish imagination as a long and bitter winter produces on the minds of grown folk. Looking back at the days of childhood, the middle-aged man or woman recalls what seems like a series of bitter winters, because recalling many occasions when, during what seemed a long time, the snow lay deep, the waters were frozen, and the outdoor air was shrewd and biting.

Before considering some of the remarkable winters which during the last century have been experienced in Great Britain and in Europe generally, I would discuss briefly the evidence on which I base the belief that the winter weather of Europe, and of Great Britain especially, has undergone no noteworthy change during the last century.

If there is any validity in the theory at present in vogue that our winters are milder now than they were forty or fifty years ago, and the theory in vogue as we have seen forty years ago that the winters then were milder than they had been forty or fifty years earlier, it is manifest that there ought to be a very remarkable contrast between our present winter weather and that which was commonly experienced eighty or ninety years since. Now, it so chances that we possess a record of the weather from 1768 to 1792, by a very competent observer—Gilbert White of Selborne—which serves to show what weather prevailed generally during that interval; while the same writer has described at length, in his own happy and effective manner, some of the winters which were specially remarkable for severity. Let us see whether the winters during the last third of the eighteenth century were so much more bitter or long-lasting than those now experienced as common ideas on the subject would suggest.

In 1768, the year began with a fortnight's frost and snow. The cold was very severe, as will presently be more particularly noted. Thereafter wet and rainy weather prevailed to the end of February. The winter of 1768-69 was marked throughout by alternations of rain and frost; thus from the middle of November to the end of 1768 there were 'alternate rains and frosts;' in January and February, 1769, the weather was 'frosty and rainy, with gleams of fine weather in the intervals; then to the middle of March, wind and rain.' The last half of November, 1769, was dry and frosty, December windy, with rain and intervals of frost, and the first fortnight very foggy; the first fortnight of January, 1770, frosty, but on the 14th and 15th all the snow melted and to the end of February mild hazy weather prevailed; March was frosty and bright. From the middle of October, 1770, to the end of the year, there were almost incessant rains; then severe frosts till the last week of January, 1771, after which rain and snow prevailed for a fortnight, followed by spring weather till the end of February. March and April were frosty. The spring of 1771 was so exceptionally severe in the Isle of Skye that it was called the Black Spring; in the south also it was severe. November, 1771, frost with intervals of fog and rain; December, mild and bright weather with hoar frosts; January and the first week of February, 1772, frost and snow; thence to the end of the first fortnight in March, frost, sleet, rain, and snow.

The winter of 1772-73 would fairly compare with the mildest in recent years, except for one fortnight of hard frost in February, 1773. For from the end of September to December 22 there were rain and mild weather—the first ice on December 23—but thence to the end of the month foggy weather. The first week in January, frost, but the rest of the month dark rainy weather; and after the fortnight of hard frost in February, misty showery weather to the end of the first week in March, and bright spring days till April.

There were four weeks of frost after the end of the first fortnight in November, 1773, then rain to the end of the year, and rain and frost alternately to the middle of March, 1774.

In 1774-1775 there seems to have been no winter at all worth mentioning. From August 24 to the end of the third week in November there was rain, with frequent intervals of sunny weather. Then to the end of December, dark dripping fogs. January, February, and the first half of March, 1775, rain almost every day; and to the end of the first week in April, cold winds, with showers of rain and snow.

The end of the year 1775 was rainy, with intervals of hoar frost and sunshine. Dark frosty weather prevailed during the first three weeks of January, 1776, with much snow. Afterwards foggy weather and hoar frost. The cold of January, 1776, was remarkable, and will presently be more fully described.

November and December, 1776, were dry and frosty, with some days of hard rain. Then to January 10, 1777, hard frost; to the 20th foggy with frequent showers; and to February 18, hard dry frost with snow, followed by heavy rains, with intervals of warm dry spring weather to the end of May.

The winter of 1777-78 was another which resembled closely enough those winters which many suppose to be peculiar to recent years. The autumn weather to October 12 had been remarkably fine and warm. From then to the end of the year, grey mild weather prevailed, with but little rain and still less frost. During the first thirteen days of January there was frost with a little snow; then rain to January 24, followed by six days of hard frost. After this, harsh foggy weather with rain prevailed till February 23; then five days of frost; a fortnight of dark harsh weather; and spring weather to the end of the first fortnight in April. The second fortnight of April, however, was cold, with snow and frost.

Similarly varied in character was the winter of 1778-79. From the end of September, 1778, to the end of the year the weather was wet, with considerable intervals of sunshine. January, 1779, was characterised by alternations of frost and showers. After this, to April 21, warm dry weather prevailed.

The winter of 1779-80 was rather more severe. During October and November the weather was fine with intervals of rain. December rainy, with frost and snow occasionally. January 1780, frosty. During February dark harsh weather prevailed, with frequent intervals of frost. March was characterised by warm, showery, spring weather.

November and December, 1781, were warm and rainy; and the same mild open weather prevailed till February 4. Then followed eighteen days of hard frost, after which to the end of March the weather was cold and windy, with frost, snow, and rain. Thus the first two-thirds of the winter of 1781-82 were exceptionally mild, while the last third was cold and bleak.

In November, 1782, we find for the first time in these records an instance of early and long-continued cold. 'November began with a hard frost, and continued throughout, with alternate frost and thaw. The first part of December frosty.' The latter half of December, however, and the first sixteen days of January were mild, with much rain and wind. Then came a week of hard frost, followed by stormy dripping weather to the end of February. Thence to May 9, cold harsh winds prevailed. On May 5 there was thick ice.

The next two winters were, on the whole, the severest of the entire series recorded by Gilbert White, though at no time in the winter of 1783-84 was the cold greater than has often been experienced in this country. White's record runs thus: From September 23 to November 12, dry mild weather. To December 18, grey soft weather with a few showers. Thence to February 19, 1784, hard frost, with two thaws, one on January 14, the other on February 5. To February 28, mild wet fogs. To March 3, frost with ice. To March 10, sleet and snow. To April 2, snow with hard frost.

The winter of 1784-85 was remarkable for the exceedingly severe cold of December, 1784, which will presently be referred to more particularly. From November 6 to the end of the year 1784, fog, rain, and hard frost alternated, the frost continuing longest and being severest in December. On January 2 a thaw began, and rainy weather with wind continued to January 28. Thence to March 15 hard frost; to March 21 mild weather with sprinkling showers; to April 7 hard frost.

After rainy weather till December 23, 1786, came frost and snow till January 7, 1787. Then a week of mild and very rainy weather, followed by a week of heavy snow. From January 21 to February 11, mild weather with frequent rains; to February 21 dry weather with high winds; and to March 10, hard frost. Then alternate rains and frosts to April 13.

Early in November, 1786, there was frost, but thence to December 16 rain with only 'a few detached days of frost.' After a fortnight of frost and snow, came 24 days of dark, moist, mild weather. Then four days (from January 24 to January 28, 1787) of frost and snow; after which mild showery weather to February 16, dry cool weather to February 28, stormy and rainy weather to March 10. The next fortnight bright and frosty; then mild rainy weather to the end of April.

November, 1787, was mild till the 23rd, the last week frosty. The first three weeks of December still and mild, with rain, the last week frosty. The first thirteen days of January mild and wet; then five days of frost, followed by dry, windy weather. February frosty, but with frequent showers. The first half of March hard frost, the rest dark harsh weather with much rain.

The winter of 1788-89 was very severe, hard frost continuing from November 22, 1788, to January 13, 1789. The rest of January was mild with showers. February rainy, with snow showers and heavy gales of wind. The first thirteen days of March hard frost, with snow, and then till April 18, heavy rain, with frost, snow, and sleet. This winter was very severe also on the Continent.

The winter of 1789-90 was as mild as that of 1788-89 had been severe. The record runs thus:—'November to 17th, heavy rains with violent gales of wind. To December 18, mild dry weather with a few showers. To the end of the year rain and wind. To January 16, 1790, mild foggy weather, with occasional rains. To January 21' (five days only) 'frost. To January 28, dark, with driving rains. To February 14, mild dry weather. To February 22' (eight days) 'hard frost.' To April 5 bright cold weather with a few showers.

In November, 1790, mild autumnal weather prevailed till the 26th, after which there were five days of hard frost. Thence to the end of the year, rain and snow, with a few days of frost. The whole of January, 1791, was mild with heavy rains; February windy, with much rain and snow. Then to the end of April dry, but 'rather cold and frosty.'

November, 1791, was very wet and stormy, December frosty. There was some hard frost in January, 1792, but the weather mostly wet and mild. In February also there was some hard frost and a little snow. March was wet and cold.

The record ends with the year 1792, the last three months of which are thus described: 'October showery and mild. November dry and fine. December mild.'

Certainly the account of the 23 years between 1768 and 1792 does not suggest that there is any material difference between the winter weather now common and the average winter weather a century ago. Still it may be necessary to show, that when men spoke of mild weather in old times, they meant what we should understand by the same expression. A reference to rain or showery weather shows sufficiently that a temperature above the freezing point existed while such weather prevailed. But it might be that what White speaks of as mild weather, is such as we should consider severe. In order to show that this is not the case, it will suffice to examine his statement respecting the actual temperature in particular winters, considering them always with due reference to what he says as to their exceptional character.

Take for instance his account of the frost in January, 1768. He says that, for the short time it lasted, this frost 'was the most severe that we had then known for many years, and was remarkably injurious to evergreens.' 'The coincidents attending this short but intense frost,' he proceeds, after describing his vegetable losses, 'were, that the horses fell sick with an epidemic distemper, which injured the winds of many and killed some; that colds and coughs were general among the human species; that it froze under people's beds for several nights; that meat was so hard frozen that it could not be spitted, and could not be secured but in cellars, &c.' On the 3rd of January a thermometer within doors, in a close parlour, where there was no fire, fell in the night to 20; on the 4th to 18; and on the 7th to 17½ degrees, 'a degree of cold which the owner never since saw in the same situation.' The evidence from the thermometer is unsatisfactory, because we do not know how the parlour was situated. But there is reason for supposing that in the bitterest winters known during the last thirty or forty years, a greater degree of cold than that of January, 1768, has been experienced in England.

The frost of January, 1776, was also regarded as remarkable, and an account of it will therefore enable us to judge what was the ordinary winter weather of the last century.

In the first place, White notices that 'the first week of January, 1776, was very wet, and drowned with vast rains from every quarter; from whence may be inferred, as there is great reason to believe is the case, that intense frosts seldom take place till the earth is perfectly glutted and chilled with water; and hence dry autumns are seldom followed by rigorous winters.' On the 14th, after a week of frost, sleet, and snow, which after the 12th 'overwhelmed all the works of men, drifting over the tops of gates, and filling the hollow lanes,' White had occasion to be much abroad. He thought he had never before or since encountered such rugged Siberian weather. 'Many of the narrow roads were now filled above the tops of the hedges, through which the snow was driven into most romantic and grotesque shapes, so striking to the imagination as not to be seen without wonder and pleasure. The poultry dared not to stir out of their roosting places: for cocks and hens are so dazzled and confounded by the glare of snow, that they would soon perish without assistance. The hares also lay sullenly in their seats, and would not move till compelled by hunger: being conscious, poor animals, that the drifts and heaps treacherously betray their footsteps and prove fatal to many of them.' From the 14th the snow continued to increase, and began to stop the road-wagons and coaches, which could no longer keep their regular stages; and especially on the Western roads. 'The company at Bath that wanted to attend the Queen's birthday were strangely incommoded; many carriages of persons who got on their way to town from Bath, as far as Marlborough, after strange embarrassments, here met with a ne plus ultra. The ladies fretted, and offered large rewards to labourers, if they would shovel them a road to London; but the relentless heaps of snow were too bulky to be removed; and so the 18th passed over, leaving the company in very uncomfortable circumstances, at the Castle and other inns.'

Yet all this time and till the 21st the cold was not so intense as it was in December 1878. On the 21st the thermometer showed 20 degrees, and had it not been for the deep snows, the winter would not have been very severely felt. On the 22nd, the author had occasion to go to London 'through a sort of Laplandian scene, very wild and grotesque indeed.' But London exhibited an even stranger appearance than the country. 'Being bedded deep in snow, the pavement of the streets could not be touched by the wheels or the horses' feet, so that the carriages ran almost without the least noise.' 'Such an exemption from din and clatter,' says White, 'was strange but not pleasant; it seemed to convey an uncomfortable idea of desolation:

Ipsa silentia terrent.

'The worst had not yet, however, been reached. On the 27th much snow fell all day, and in the evening the frost became very intense. At South Lambeth, for the four following nights, the thermometer fell to eleven, seven, six, six; and at Selborne to seven, six, ten; and on the 31st, just before sunrise, with rime on the trees and on the tube of the glass, the quicksilver sank exactly to zero—a most unusual degree of cold this for the South of England.' During these four nights, the cold was so penetrating that ice formed under beds; and in the day the wind was so keen, that persons of robust constitutions could hardly endure to face it. 'The Thames was at once frozen over, both above and below bridge, that crowds ran about on the ice. The streets were now strangely encumbered with snow, which crumbled and trod dusty; and turning gray, resembled bay salt; what had fallen on the roofs was so perfectly dry that from first to last it lay twenty-six days on the houses in the city; a longer time than had been remembered by the oldest housekeepers living.'

According to all appearances rigorous weather might now have been expected for weeks to come, since every night increased in severity. 'But behold,' says White, 'without any apparent cause, on February 1, a thaw took place, and some rain followed before night, making good the observation that frosts often go off as it were at once without any gradual declension of cold. On February 2 the thaw persisted, and on the 3rd swarms of little insects were frisking and sporting in a court-yard at South Lambeth, as if they had felt no frost. Why the juices in the small bodies and smaller limbs of such minute beings are not frozen, is a matter of curious inquiry.'

Although it is manifest that the weather of January, 1776, was severe, yet the remarks italicised show that such weather was regarded a century ago as altogether exceptional. Again, the cold lasted only about three weeks. And it may be doubted whether in actual intensity it even equalled that which was experienced in London and the south of England generally during the first week of 1855. Certainly the evidence afforded by such remarks as I have italicised in the above-quoted passage tends more to prove that winter weather in England a hundred years hence was on the average much like winter at present, than the unusual severity of the weather during about twenty-four days in January, 1776, tends to suggest that a marked change has taken place.

Similar evidence is afforded by White's remarks respecting the severe cold of December, 1784.

As in January, 1776, so in December, 1784—a week of very wet weather heralded the approach of severe cold. 'The first week of December,' says White, 'was very wet, with the barometer very low. On the 7th, with the barometer at 28.5, came on a vast snow, which continued all that day and the next, and most part of the following night: so that by the morning of the 9th the works of men were quite overwhelmed' (there is something quite Homeric in White's use of this favourite expression), 'the lanes filled so as to be impassable, and the ground covered twelve or fifteen inches without any drifting. In the evening of the 9th the air began to be so very sharp that we thought it would be curious to attend to the motions of a thermometer; we therefore hung out two, one made by Martin and one by Dolland' (probably Dollond), 'which soon began to show us what we were to expect; for by ten o'clock they fell to twenty-one, and at eleven to four, when we went to bed. On the 10th in the morning the quicksilver of Dolland's glass was down to half a degree below zero and that of Martin's, which was absurdly graduated only to four degrees above zero, sunk quite into the brass guard of the ball, so that, when the weather became most interesting, this was useless. On the 10th, at eleven at night, though the air was perfectly still, Dolland's glass went down to one degree below zero! This strange severity of the weather made me very desirous to know what degree of cold there might be in such an exalted and near situation as Newton. We had, therefore, on the morning of the 10th, written to Mr. ----, and entreated him to hang out his thermometer, made by Adams, and to pay some attention to it, morning and evening, expecting wonderful phenomena in so elevated a region, at two hundred feet or more above my house. But, behold! on the 10th, at eleven at night, it was down only to seventeen, and the next morning at twenty-two, when mine was at ten! We were so disturbed at this unexpected reverse of comparative cold that we sent one of my glasses up, thinking that of Mr. —— must somehow be wrongly constructed. But when the instruments came to be confronted they went exactly together, so that for one night at least the cold at Newton was eighteen degrees less than at Selborne, and through the whole frost ten or twelve degrees; and indeed, when we came to observe consequences, we could readily credit this, for all my laurustines, bays, ilexes, arbutuses, cypresses, and even my Portugal laurels—and, which occasions more regret, my fine sloping laurel hedge—were scorched up, while at Newton the same trees have not lost a leaf....' One circumstance noted by White, though not bearing specially on the degree of cold which prevailed on this occasion, is very interesting. 'I must not omit to tell you,' says White, 'that during those two Siberian days my parlour cat was so electric that had a person stroked her and been properly insulated, the shock might have been given to a whole circle of people.'

White's account of this severe frost bears very significantly on the theory that our winter weather has undergone a great change. It is obvious, in the first place, that the situation of his thermometers was such that they were likely to show a low temperature as compared with the indications in other places. It is also clear that the thermometer he used was trustworthy. If it were one of Dollond's it would presumably be a good one, and I do not think that in White's time the trick of marking inferior instruments with the name Dolland had come into vogue. But in any case Adams's scientific instruments were excellent; and, as the account shows, the thermometer used by White indicated the same temperature as Adams's. Now, the lowest temperature recorded was only one degree below zero; and that this was altogether exceptional is shown not only by what White says in the passage I have quoted, but also by his remarking a little later that this frost 'may be allowed, from its effects, to have exceeded any since 1739-40.' Even this is not all. It would certainly prove beyond dispute that our winters were not milder than those of a century ago; for a greater degree of cold than that recorded by White in December, 1784, has been more than once experienced in the same part of England during the last forty years. But it seems from a statement in Miller's 'Gardener's Dictionary,' that the Portugal laurels were untouched in the great frost of 1739-40, which would show that the frost of 1784 was more severe and destructive than that of 1739-40. If this were really so, the frost of 1784 was the severest (though owing to its short duration it did not produce the most remarkable effects in the country at large) of any during the periods noted between the years 1709 and 1788. On the Continent, the frost of December, 1788, was more severe in some places, though rather less severe at Paris, than that of 1709; but I do not know of any records which would enable us to make a direct comparison between the cold in 1709, 1784, and 1788, at any given place in Great Britain.

It will be well now to take a wider survey and consider some of the most severe winters experienced in Europe generally.

The winter of 1544 was remarkably severe all over Europe. In Flanders, according to Mézerai, wine froze in casks, and was sold in blocks by the pound weight. The winter of 1608 was also very severe. In the winter of 1709 the thermometer at the Paris Observatory recorded a cold of nearly ten degrees below zero.

Passing over the winter of 1776, of whose effects in England we have learned enough to enable us to judge how severely it must have been felt in those continental countries where the winter is always more severe than with us, we come to the severe winter of 1788-89.

We have seen that in England hard frost began on November 22 and continued till January 13. In France (or rather at Paris) the frost began three days later, but the thaw began on the same day, January 13. There was no intermission except on Christmas Day, when it did not freeze. In the great canal at Versailles the ice was two feet thick. 'The water also froze,' says Flammarion, 'in several very deep wells, and wine became congealed in cellars. The Seine began to freeze as early as November 26, and for several days its course was impeded, the breaking up of the ice not taking place until January 20 (1789). The lowest temperature observed at Paris was seven degrees below zero, on December 31. The frost was equally severe in other parts of France and throughout Europe. The Rhone was quite frozen over at Lyons, the Garonne at Toulouse, and at Marseilles the sides of the docks were covered with ice. Upon the shores of the Atlantic the sea was frozen to a distance of several leagues. The ice upon the Rhine was so thick that loaded wagons were able to cross it. The Elbe was covered with ice, and also bore up heavy carts. The harbour at Ostend was frozen so hard that people could cross it on horseback; the sea was congealed to a distance of four leagues from the exterior fortifications, and no vessel could approach the harbour.'

It was during the frost of 1788-89 that a fair was held on the Thames. The river was frozen as low as Gravesend; but it was only in London that booths were set up. The Thames fair lasted during the Christmas holidays and the first twelve days of January.

At Strasburg, on December 31, a temperature of fifteen degrees below zero was shown. At Berlin on the 20th, and St. Petersburg on the 12th, temperatures of twenty and twenty-three degrees below zero respectively were noted. But in Poland and parts of Germany an even greater degree of cold was recorded. For instance, at Warsaw, 26½ degrees below zero; and at Bremen thirty-two degrees. At Basle, on December 18, the thermometer indicated nearly thirty-six degrees below zero. In the district around Toulouse bread was frozen so hard that it could not be cut till it had been laid before the fire. Many travellers perished in the snow. At Lemburg, in Galicia, thirty-seven persons were found dead in three days towards the end of December. The ice froze so thick in ponds that in most of them all the fish were killed.

The winter of 1794-95 was remarkable in this country as giving the lowest average temperature for a month ever recorded in England. The mean temperature for January, 1795, was only 26.5 degrees; or more than three degrees lower than that of last January. January 25, 1795, is commonly supposed to have been the coldest day ever known. The thermometer in London stood at eight degrees below zero during part of that bitter day; and in Paris, where also there were six consecutive weeks of frost, at 10-3/7 degrees below zero. The Thames was frozen over at Whitehall in the beginning of January. The Marne, the Scheldt, the Rhine, and the Seine were so frozen over that army corps and heavy carriages crossed over them. Perhaps the strangest of all the recorded results of cold weather occurred during the same month. The French General Pichegru, who was then operating in the North of Holland, sent detachments of cavalry and infantry about January 20, with orders to the former to cross the Texel and to capture the enemy's vessels, which were 'imprisoned by the ice.' 'The French horsemen crossed the plains of ice at full gallop,' we are told, 'approached the vessels, called on them to surrender, captured them without a struggle, and took the crews prisoners:' probably the only occasion in history when effective use could have been made of a corps of horse-marines.

The winter of 1798-99 was very cold, but not so exceptionally cold in England as on the Continent. The Seine was completely frozen over from the 29th of December to the 19th of January, from the Pont de la Tournelle to the Pont Royal. Farther east the cold was much greater. The Meuse was frozen over so thickly that carriages could cross it, and at the Hague and at Rotterdam fairs were held on the river. A regiment of dragoons starting from Mayence, crossed the Rhine upon the ice.

The winter of 1812-13 was exceeding cold in November, December and January. It was this unusually early and bitter winter which occasioned the destruction of Napoleon's army in Russia, and the eventual overthrow of his power. (For no one who considers his achievements during the campaigns of 1813 and 1814 can doubt that, had the army with which he invaded Russia been at his command, he would have foiled all the efforts of combined Europe against him.) The cold became very intense in Russia after the 7th of November. On the 17th the thermometer fell to 15 degrees below zero, according to Larrey, who carried a thermometer suspended from his button hole. The retreat from Moscow began on the 18th, Napoleon leaving the still burning city on the 19th, and the evacuation being complete on the 23rd. Everything seemed to conspire against Napoleon and his army. During the march to Smolensk snow fell almost incessantly. Even the only intermission of the cold during the retreat caused additional disaster. On the 18th of November, Russian troops had crossed the frozen Dwina with their artillery. A thaw begun on the 24th, but continued only for a short time; 'so that from the 26th to the 29th the Beresina contained numerous blocks of ice, but yet was not so frozen over as to afford a passage to the French troops.' It was to this circumstance that the terribly disastrous nature of the passage of the Beresina must mainly be attributed.

The winter of 1813-14 was colder in England than on the Continent—I mean, the winter here was colder for England than the winter in any region of continental Europe was for that region. The frost lasted from December 26 to March 21, and the mean temperature of January was only 26.8 degrees. The Thames was frozen over very thickly, and a fair was held on the frozen river.

The winter of 1819-20 was bitter throughout Europe. Mr. Thomas Plant, in an interesting letter to the Times of February 4, says that this winter was one long spell of intense frost from November to March, and was almost as severe as that of 1813-14. In Paris there were forty-seven days of frost, nineteen of which were consecutive, from December 30, 1818, to January 17. 'In France,' says Flammarion, 'the intensity of the cold was heralded by the passage along the coast of the Pas de Calais of a great number of birds coming from the farthest regions of the north by wild swans and ducks of variegated plumage. Several travellers perished of cold; amongst others a farmer near Arras, a gamekeeper near Nogent (Haute Marne) a man and woman in the Côte d'Or, two travellers at Breuil, on the Meuse, a woman and a child on the road from Etain to Verdun, six persons near Château Salins (Meurthe), and two little Savoyards on the road from Clermont to Chalons-sur-Saône. In the experiments made at the Metz School of Artillery, on the 10th of January, to ascertain how iron resisted low temperatures, several soldiers had their hands or their ears frozen.' During this winter the Thames, the Seine, the Rhône, the Rhine, the Danube, the Garonne, the lagoons of Venice, and the Sound, were so far frozen that it was possible to walk across them on the ice.

The winter of 1829-30 was remarkable as the longest winter of the first half of the present century. The cold was not exceptionally intense, but the long continuance of bitter weather occasioned more mischief in the long run than has attended short spells of severer cold. The river Seine was frozen at Paris first for twenty-nine days, from December 28th to January 26th, and then for five days from February 5th to February 10th. The river had not been so many days frost-bound in any winter since 1763. Even at Havre the Seine was frozen over; and at Rouen a fair was held upon the river on January 18th. On January 25, after a thaw of six days, the ice from Corbeil and Melun blocked up the bridge at Choisy, forming a wall 16½ feet high.

The winter of 1837-38 was remarkable for the long frost of January and February, 1838. It lasted eight weeks. Mr. Plant mentions that 'the lowest point of the thermometer during this long and severe frost occurred on January 20, when the readings were from 5 degrees below zero, in this district' (Moseley, near Birmingham), 'to 8 and 10 degrees below zero in more exposed aspects.' 'On the 13th of January, the old Royal Exchange, London, was destroyed by fire; and the frost was so great that, when the fire brigade had ceased playing on one portion of the burning pile, the water in a short time became icicles of such large dimensions, that the effect has been described as grand in the extreme.'

The winter of 1837-38 is not usually included as one among the exceptionally cold winters on the Continent, and the winter of 1840-41, though certainly cold in the British Isles, is not included by Mr. Plant in his list of the coldest winters since 1795. But this winter was exceedingly cold on the Continent. At Paris there were fifty-nine days' frost, twenty-seven of them consecutive—viz. from December 5th, when the cold began, to January 1st. The intermission which began on January 1, lasted only till January 3, when there was another week of frost. There was frost again from January 30 to February 10. One of the most remarkable stories connected with the cold of this winter is thus told by Flammarion:—'On the 15th of December, the ashes of Napoleon, brought back from St. Helena, entered Paris by the Arc de Triomphe. The thermometer in places exposed to nocturnal radiation, had that day marked 6.8 degrees above zero. An immense crowd, the National Guard of Paris and its suburbs, and numerous regiments lined the Champs Elysées, from the early morning until two in the afternoon. Every one suffered severely from the cold. Soldiers and workmen, hoping to obtain warmth by drinking brandy' (the most chilling process they could have thought of), 'were seized by the cold, and dropped down dead of congestion. Several persons perished, victims of their curiosity: having climbed up into the trees to see the procession, their extremities, benumbed by the cold, failed to support them, and they were killed by the fall.'