Chapter IV · (continued 2)

After about eight months' work at Bristol he published a volume of "Researches," which contained a great many new facts, and was characterized by vigour and novelty of conception. These researches had been carried out with intense application; each was struck off at a red heat. His mind during this time was filled with vast scientific conceptions, and he began also to think of fame. "An active mind, a deep ideal feeling of good, and a look towards future greatness," he tells us, sustained him.

Count Rumford, the founder of the Royal Institution in London, was anxious to obtain a lecturer on chemistry for the Institution. Davy was strongly recommended, and after a little arrangement—concerning which Davy says in a letter, "I will accept of no appointment except on the sacred terms of independence"—he was appointed Assistant Lecturer on Chemistry and Director of the Laboratory. About a year later his official designation was changed to Professor of Chemistry. This appointment opened up a great sphere of research; "the sole and uncontrolled use of the apparatus of the institution for private experiments" was to be granted him, and he was promised "any apparatus he might need for new experiments."

He had now the command of a good laboratory; he had not to undergo the drudgery of systematic teaching, but was only required to give lectures to a general audience. Before leaving Bristol he had commenced experiments on the chemical applications of the voltaic battery; these he at once followed up with the better apparatus now at his command. The results of this research, and his subsequent work on the alkalis and on muriatic acid and chlorine, have been already described. The circumstances of Davy's life had hitherto been most favourable; how nobly he had availed himself of these circumstances was testified by the work done by him.

His first lecture was delivered in the spring of 1801, and at once he became famous. A friend of Davy says, "The sensation created by his first course of lectures at the Institution, and the enthusiastic admiration which they obtained, is scarcely to be imagined. Men of the first rank and talent, the literary and the scientific, the practical and the theoretical, blue-stockings and women of fashion, the old and the young—all crowded, eagerly crowded the lecture-room. His youth, his simplicity, his natural eloquence, his chemical knowledge, his happy illustrations and well-conducted experiments, excited universal attention and unbounded applause. Compliments, invitations and presents were showered upon him in abundance from all quarters; his society was courted by all, and all appeared proud of his acquaintance." One of his biographers says of these lectures, "He was always in earnest, and when he amused most, amusement appeared most foreign to his object. His great and first object was to instruct, and in conjunction with this, maintain the importance and dignity of science; indeed, the latter, and the kindling a taste for scientific pursuits, might rather be considered his main object, and the conveying instruction a secondary one."

The greatest pains were taken by Davy in the composition and rehearsal of his lectures, and in the arrangement of experiments, that everything should tend towards the enlightenment of his audience. Surrounded by a brilliant society, invited to every fashionable entertainment, flattered by admirers, tempted by hopes of making money, Davy remained a faithful and enthusiastic student of Nature. "I am a lover of Nature," he writes at this time to a friend, "with an ungratified imagination. I shall continue to search for untasted charms, for hidden beauties. My real, my waking existence, is amongst the objects of scientific research. Common amusements and enjoyments are necessary to me only as dreams to interrupt the flow of thoughts too nearly analogous to enlighten and vivify."

During these years (i.e. from 1802 to 1812) he worked for the greater part of each day in the laboratory. Every week, almost every day, saw some fresh discovery of importance. He advanced from discovery to discovery. His work was characterized by that vast industry and extreme rapidity which belong only to the efforts of genius. Never, before or since, has chemical science made such strides in this country.

In 1803 Davy was elected a Fellow, and in 1807 one of the secretaries of the Royal Society. In 1812 he retired from the professorship of chemistry at the Royal Institution; in the same year he was made a knight.

The next two or three years were mostly spent in travelling abroad with his wife—he had married a widow lady, Mrs. Apreece, in 1812. During his visit to Paris he made several experiments on the then recently discovered iodine, and proved this substance to be an element.

The work which Davy had accomplished in the seventeen years that had now elapsed since he began the study of chemistry, whether we consider it simply as a contribution to chemical science, or in the light of the influence it exerted on the researches of others, was of first-rate importance; but a fresh field now began to open before him, from which he was destined to reap the richest fruits. In the autumn of 1815 his attention was drawn to the subject of fire-damp in coal-mines. As he passed through Newcastle, on his return from a holiday spent in the Scottish Highlands, he examined various coal-mines and collected samples of fire-damp; in December of the same year his safety-lamp was perfected, and soon after this it was in the hands of the miner.

The steps in the discovery of this valuable instrument were briefly these. Davy established the fact that fire-damp is a compound of carbon and hydrogen; he found that this gas must be mixed with a large quantity of ordinary air before the mixture becomes explosive, that the temperature at which this explosion occurs is a high one, and that but little heat is produced during the explosion; he found that the explosive mixture could not be fired in narrow metallic tubes, and also that it was rendered non-explosive by addition of carbonic acid or nitrogen. He reasoned on these facts thus: "It occurred to me, as a considerable heat was required for the inflammation of the fire-damp, and as it produced in burning a comparatively small degree of heat, that the effect of carbonic acid and azote, and of the surfaces of small tubes, in preventing its explosion, depended on their cooling powers—upon their lowering the temperature of the exploding mixture so much that it was no longer sufficient for its continuous inflammation." He at once set about constructing a lamp in which it should be impossible for the temperature of ignition of a mixture of fire-damp and air to be attained, and which therefore, while burning, might be filled with this mixture without any danger of an explosion. He surrounded the flame of an oil-lamp with a cylinder of fine wire-gauze; this lamp when brought into an atmosphere containing fire-damp and air could not cause an explosion, because although small explosions might occur in the interior of the wire cylinder, so much heat was conducted away by the large metallic surface that the temperature of the explosive atmosphere outside the lamp could not attain that point at which explosion would occur.

In 1818 Sir Humphry Davy was made a baronet, in recognition of his great services as the inventor of the safety-lamp; and in 1820 he was elected to the most honourable position which can be held by a man of science in this country, he became the President of the Royal Society.

For seven years he was annually re-elected president, and during that time he was the central figure in the scientific society of England. During these years he continued his investigations chiefly on electro-chemical subjects and on various branches of applied science. In 1826 his health began to fail. An attack of paralysis in that year obliged him to relinquish most of his work. He went abroad and travelled in Italy and the Tyrol, sometimes strong enough to shoot or fish a little, or even to carry on electrical experiments; sometimes confined to his room, or to gentle exercise only. He resigned the presidentship of the Royal Society in 1827. In 1828 he visited Rome, where he was again attacked by paralysis, and thought himself dying, but he recovered sufficiently to attempt the journey homeward. At Geneva he became very ill, and expired in that city on the 29th of May 1829.

During these later years of illness and suffering, his intense love of and delight in Nature were very apparent; he returned again to the simple tastes and pleasures of his early days. His intimate knowledge of natural appearances and of the sights and sounds of country life is conspicuous in the "Salmonia, or Days of Fly-fishing," written during his later years.

Sir Humphry Davy was emphatically a genius. He was full of eager desire to know the secrets of the world in which he lived; he looked around him with wonder and delight, ever conscious of the vastness of the appearances which met his gaze; an exuberance of life and energy marked his actions; difficulties were encountered by him only to be overcome; he was depressed by no misfortunes, deterred by no obstacles, led aside from his object by no temptations, and held in bondage by no false analogies.

His work must ever remain as a model to the student of science. A thorough and careful foundation of fact is laid; on this, hypotheses are raised, to be tested first by reasoning and argument, then by the tests of the laboratory, which alone are final. Analogies are seized; hints are eagerly taken up, examined, and acted on or dismissed. As he works in the laboratory, we see his mind ranging over the whole field of chemical knowledge, finding a solution of a difficulty here, or guessing at a solution there; combining apparently most diverse facts; examining phenomena which appear to have no connection; never dwelling too long on an hypothesis which cannot yield some clue to the object of research, but quickly discovering the road which will lead to the wished-for solution.

Like so many great experimenters Davy accomplished wonders with little apparatus. When he went abroad for the first time he took with him two small boxes, one twenty, and the other twelve inches long, by about seven inches wide and four deep. With the apparatus contained in these boxes he established the elementary nature of iodine, and made a rough estimation of its atomic weight; he determined many of its analogies with chlorine, proving that, like chlorine, it is markedly electro-negative, and that its compounds are decomposed by chlorine; he accomplished the synthesis of hydriodic acid, and approximately determined the composition of iodide of nitrogen. But when it was necessary to employ delicate or powerful apparatus, he was able by the use of that also to obtain results of primary importance. The decomposition of potash, soda, baryta, lime and strontia could not have been effected had he not had at his command the resources of a well-furnished laboratory.

Davy has had no successor in England. Much useful and some brilliant work has been done by English chemists since his day, but we still look back to the first quarter of the century as the golden age of chemistry in this country. On the roll wherein are written the names of England's greatest sons, there is inscribed but a single chemist—Humphry Davy.

I carried on the account of the work of Davy's great contemporary, Berzelius, to the time when he had fairly established dualistic views of the structure of chemical compounds, and when, by the application of a few simple rules regarding the combinations of elementary atoms, he had largely extended the bounds of the atomic theory of Dalton.

Berzelius also did important work in the domain of organic chemistry. By numerous analyses of compounds of animal and vegetable origin, he clearly established the fact that the same laws of combination, the same fixity of composition, and the same general features of atomic structure prevail among the so-called organic as among the inorganic compounds. In doing this he broke down the artificial barrier which had been raised between the two branches of the science, and so prepared the way for modern chemistry, which has won its chief triumphs in the examination of organic compounds.

By the many and great improvements which he introduced into analytical chemistry, and by the publication of his "Textbook of Chemistry," which went through several editions in French and German, and also of his yearly report on the advance of chemistry, Berzelius exerted a great influence on the progress of his favourite science. Wöhler tells us that when the spring of the year came, at which time his annual report had to be prepared, Berzelius shut himself up in his study, surrounded himself with books, and did not stir from the writing-table until the work was done.

In his later days Berzelius was much engaged in controversy with the leaders of the new school, the rise and progress of which will be traced in the next chapter, but throughout this controversy he found time to add many fresh facts to those already known. He continued his researches until his death in 1848.

The work of the great Swedish chemist is characterized by thoroughness in all its parts: to him every fact appeared to be of importance; although now perhaps only an isolated fact, he saw that some day it would find a place in a general scheme of classification. He worked in great measure on the lines laid down by Dalton and Davy; the enormous number and accuracy of his analyses established the law of multiple proportions on a sure basis, and his attempts to determine the constitution of compound atoms, while advancing the atomic theory of Dalton, drew attention to the all-important distinction between atom and molecule, and so prepared chemists for the acceptance of the generalization of Avogadro. The electro-chemical conceptions of Davy were modified by Berzelius; they were shorn of something of their elasticity, but were rendered more suited to be the basis of a rigid theory.

At the close of this transition period from the Lavoisierian to the modern chemistry, we find analytical chemistry established as an art; we find the atomic theory generally accepted, but we notice the existence of much confusion which has arisen from the non-acceptance of the distinction made by Avogadro between atom and molecule; we find the analogies between chemical affinity and electrical energy made the basis of a system of classification which regards every compound atom (or molecule) as built up of two parts, in one of which positive, and in the other negative electricity predominates; and accompanying this system of classification we find that an acid is no longer regarded as necessarily an oxygen compound, but rather as a compound possessed of certain properties which are probably due to the arrangement of the elementary atoms, among which hydrogen appears generally to find a place; we find that salts are for the most part regarded as metallic derivatives of acids; and we find that by the decomposition of the supposed elementary substances, potash, soda, lime, etc., the number of the elements has been extended, the application of a new instrument of research has been brilliantly rewarded, and the Lavoisierian description of "element" as the "attained, not the attainable, limit of research" has been emphasized.

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