Зображення сторінки
PDF
ePub

scientific basis. With this purpose he (in 1829) undertook the editorship, and, to a considerable extent, the cost of a publication which he hoped would conduce to the end in view. This work, which was entitled 'Records of Mining,' did not meet with the support he had looked for, and was not continued; but the part published contains four contributions from his own pen. One of these, which deserves especial notice, is an excellent and well-digested paper, in which he advocates the establishment of a School of Mines in Cornwall, and presents a "Prospectus," setting forth the details of a plan for the foundation, government, and maintenance of an institution of that kind, and for regulation of the instruction it should afford. This proposal did not meet with encouragement at the time, but the establishment of the present School of Mines, although he had no active share in it, may be traced to Mr. Taylor's earnest and judicious representations.

In 1812 Mr. Taylor settled in London, and engaged with his brother in a chemical manufactory at Stratford in Essex; but although he had long applied himself to chemistry as a scientific pursuit, and attained a high reputation as a metallurgic chemist, he was compelled to relinquish it as a profession in consequence of the increased extent and importance of his mining business.

Throughout his eminently practical life Mr. Taylor strove constantly to maintain a healthy reciprocity between science and practice; and while availing himself of his scientific knowledge for the improvement of technical processes, he was no less earnest in turning to account his experience and opportunities as a mining engineer and metallurgist for the promotion of the sciences of geology, mineralogy, and chemistry. We accordingly find his name enrolled as a member of various scientific bodies, both British and Foreign. He was one of the earliest Fellows of the Geological Society, and from 1816 to 1844 filled the office of its Treasurer. In 1825 he was elected a Fellow of the Royal Society, and repeatedly served on the Council. But of the several Societies to which he belonged, the British Association for the Advancement of Science has been the most indebted to Mr. Taylor's useful cooperation, both scientific and administrative. He was, indeed, present at its birth, and the first meeting of its first Council was held at his house. This was on the 26th of June 1832. He was also the first Treasurer, and held that office till September 1861, when the infirmities of age constrained him to retire from it. On relieving him from the duties he had so long and so well discharged, the Council of the Association joined in a unanimous expression of respect for his character and gratitude for his long and valuable services to the cause of science. The Council of University College, London, expressed themselves in no less respectful and grateful terms when, for the same reason, he retired from the Treasurership of that Institution, which he had held for many years.

WILLIAM TOOKE was born on the 22nd of November 1777, at St. Peters

burg, where his father was then Chaplain to the factory of the Russian Company. Mr. Tooke was a solicitor by profession, but amidst the calls of business he was able to devote much time and attention to public affairs, and took part in the formation of various public institutions which were established during the active period of his life. He was long a leading member and Vice-President of the Society of Arts, and was elected President on the vacancy caused by the death of His Royal Highness the Prince Consort. His election to the Royal Society was in 1818. From 1832 to 1837 he sat in Parliament for the borough of Truro. Besides a compilation on French history, in two volumes, which appeared in 1855, and occasional contributions to magazines, Mr. Tooke, when a young man, published, anonymously, an edition of Churchill's Poems, with notes and a Life of the Author, which was favourably reviewed by Southey. He died in London on the 20th September 1863.

[graphic]

Rear-Admiral JOHN WASHINGTON was born on the 1st of January 1801. He entered the Navy in 1812, on board the 'Juno,' fitting for the American station, where he served for the next two years, and took part in various active and successful operations against the enemy. In 1814 he returned to England, and entered the Royal Naval College at Portsmouth. During the two years he spent as a student in that Institution he applied himself diligently to the scientific study of his profession, and laid the foundation of that skill and accomplishment which he afterwards attained in nautical surveying and hydrography, and through which in the after course of his life he was able to render much valuable service to the maritime interests of this and other countries.

After serving at sea for some years, and rising to the rank of Commander, he returned home for a time, but in 1841 he was appointed to continue the Survey of the North Sea, in which duty he was employed until the close of 1844. In 1842 he was promoted to the rank of Post Captain.

This Survey was Captain Washington's last service afloat; but his experience and judgment were turned to public account at different times, when he acted as a Royal Commissioner on important questions affecting the interests of navigation and of our maritime industry. In 1853 he visited some of the Russian fortresses in the Baltic, and the results of his observations proved of the greatest value in the conduct of the warlike operations which soon followed.

On the retirement of Sir Francis Beaufort, Captain Washington was appointed Hydrographer to the Admiralty, and was promoted to the rank of Rear-Admiral in 1862. His anxious and unremitting application to the various duties of his office is believed by his friends to have shortened his valuable life, which was closed at Prasu Hayre, on the

September 1863. He was a

and abroad, and was Secretar

1835 to 1841. His election into the Royal Society is dated February 13,

1845.

CÉSAR MANSUÈTE DESPRETZ was born at Lessines in Belgium, on the 13th of May 1789. At an early age he came to Paris for the purpose of devoting himself to the study of chemistry and physics. His intelligence and industry soon attracted the attention of Gay-Lussac, who appointed him répétiteur of his course of lectures on Chemistry at the École Polytechnique. He became the Professor of Physics at the Sorbonne in 1837, having previously held a similar office in the École Polytechnique and the College Henri IV. In 1822 the Academy awarded him the prize for the best memoir on the causes of animal heat. In 1825 he published an elementary treatise on Physics, which in 1836 reached a fourth edition; and in 1830 the Elements of Theoretical and Practical Chemistry. He was the author of numerous memoirs published in the 'Annales de Chimie' and in the Comptes Rendus,' dating from 1817 up to 1858. These memoirs give an account of researches on the specific heat and conductivity of metals and various mineral substances; on the propagation of heat in liquids; on the transmission of heat from one solid body to another; on the heat absorbed in fusion; on the elastic force of vapours; on the density and latent heat of vapours; on the compressibility of liquids; on the density of gas under different pressures; on the displacement and oscillations of the freezing-point of the mercurial thermometer; on the heat developed during combustion; on the expansion of water, and the temperature at which water and saline solutions attain a maximum density; on the modifications which metals undergo under the joint action of heat and ammoniacal gas; on the chemical action of voltaic electricity, the light and heat of the voltaic arc, and the intensity of the voltaic current; on the electricity developed by muscular contraction; on chloride of boron; on the decomposition of water, carbonic acid, and acetic acid; on the decomposition of salts of lead; on the limits of high and low musical notes; on the fusion and volatilization of some refractory substances under the triple action of the voltaic battery, the sun, and the oxyhydrogen blowpipe.

Though not successful in making any brilliant theoretical discoveries, the important scientific facts he has observed and arranged bring his name perpetually before the reader of any modern treatise on Physics. He laboured hard to fulfil to the utmost his duties as a Professor at the Sorbonne; and his lectures, being carefully prepared and well illustrated by experiments, attracted a numerous auditory. He was elected a Foreign Member of this Society in 1862.

His character was upright and benevolent, his tastes simple, and his habits regular in the extreme. It was his custom every year to make a long excursion in England, Germany, or Italy, by himself, and without letting any one know the day of his departure from Paris.

His last illness was preceded by several slight attacks of cerebral con

gestion. These were followed by congestion of the lungs, of which he died on the 15th of March 1863.

EILHARDT MITSCHERLICH was born on the 7th of January 1794, in the village of Jever in Oldenburg. His father was pastor of Neuende; his uncle, the well-known philologer, was Professor in Göttingen. He was educated at the Gymnasium of Jever, under the historian Schlosser. Following the example of his uncle, and encouraged by Schlosser, he devoted himself to the study of history, philology, and especially the Persian language. In order to prosecute these studies, he went in 1811 to the University of Heidelberg, and in 1813 to Paris. He had hoped to be allowed to accompany an embassy to Persia, but was prevented by the fall of Napoleon. In 1814, on his return to Germany, he commenced writing a history of the Ghurides and Kara-Chitayens, compiled from manuscripts in the Göttingen Library, and of which a specimen was published in 1815 under the title "Mirchondi historia Thaheridarum." Unwilling to renounce his favourite project of travelling in Persia, he determined to accomplish it without any extraneous assistance. The only way in which it appeared possible to travel was in the character of a physician; accordingly he resolved to study medicine. He went to Göttingen. for this purpose, and first applied himself to the introductory sciences, especially to chemistry, which so fascinated him that he gave up philology and his intention to visit Persia. In 1818 he went to Berlin for the purpose of obtaining license to lecture. Link allowed him to carry on his researches in the laboratory of the University. Here he undertook the examination of the phosphates and arseniates, and confirmed the accuracy of the latest conclusion arrived at by Berzelius, viz. that phosphoric and arsenic acid contain each five equivalents of oxygen, while phosphorous and arsenious acid contain three equivalents. He noticed at the same time that the similarly constituted phosphates and arseniates crystallized in similar forms. Up to this period he had never paid any especial attention to crystallography, but the conviction that he was on the eve of a great discovery allowed him no rest; he studied the laws of crystallography, learned the method of measuring the angles of crystals, and soon satisfied himself that the phosphates and arseniates are not merely similar but identical in form, and that, consequently, bodies exist of dissimilar composition having the same crystalline form, and that these bodies are compounds containing respectively the same number of equivalents. Many minerals appeared to confirm this law, viz. the carbonates, dolomite, chalybite, diallogite and calcite, and the sulphates, baryte, celestine, and Anglesite. In confirmation, however, of this discovery he considered it necessary to appeal to artificial salts which crystallize readily and distinctly, and are easily obtained of sufficient purity, so that his conclusions might be confirmed by any one without difficulty. The neutral sulphates of protoxide of iron, oxide of copper, oxide of zinc, and magnesia, which all con

tain water, mostly in different proportions, appeared peculiarly well fitted for this purpose. He found that the following were similar in form :(1) sulphate of copper and sulphate of protoxide of manganese; (2) sulphate of protoxide of iron and sulphate of oxide of cobalt; (3) sulphate of magnesia, sulphate of oxide of zinc, and sulphate of oxide of nickel. He also found that the salts which had dissimilar forms contained a different number of equivalents of water, and that those which had similar forms contained the same number. He then mixed the solutions of the different sulphates, and found that the resulting crystals had the form and the same number of equivalents of water as some one of the unmixed sulphates. Lastly, he examined the combinations of these sulphates with sulphate of potash, and showed that the double salts had all similar forms belonging to the oblique system, and that they were composed of one equivalent of the earthy or metallic sulphate, one equivalent of sulphate of potash, and six equivalents of water. The memoir in which these observations are recorded was presented to the Berlin Academy on the 9th of December 1819. In the course of the preceding August Berzelius came to Berlin, on his way from Paris to Stockholm. He became acquainted with Mitscherlich, and conceived such an opinion of his talents, that he suggested him to the Minister Altenstein as the most fitting successor to Klaproth in the chair of Chemistry in the University of Berlin. Altenstein did not at the moment act upon this suggestion, but consented to the proposal that Mitscherlich should perfect his chemical education by working for some time under the guidance of Berzelius. In Stockholm he continued and extended his researches on the phosphates and arseniates, and wrote a memoir on the subject, which appeared in the Transactions of the Swedish Academy. In it he described with great care the forms of the acid and neutral phosphates and arseniates of potash, soda, and ammonia, the neutral double salts of potash and soda, and of ammonia and soda, and the phosphates and arseniates of oxide of lead. He showed in every case that the phosphates and arseniates have similar forms and analogous compositions. Urged by Berzelius to give a name to this newly detected property of the chemical elements, he designated it by the term isomorphism. This discovery was of the highest importance to the theory of chemical equivalents, inasmuch as it explained the exceptions to the law of definite proportions in the mineral system of Berzelius. It appeared moreover, from the crystallization of the mixtures of the different sulphates, that isomorphous substances combine in all proportions; and that they replace one another in indefinite proportions in the composition of minerals was proved by Mitscherlich's fellow-students, Heinrich Rose and Bonsdorff, in the cases of augite and amphibole.

The doctrine of isomorphism, moreover, was an admirable test of the determination of the equivalents of the different elements, whilst the smallness of the number of changes in the equivalents of the simple substances that followed the discovery of isomorphism, is an indication of the

« НазадПродовжити »