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DAV experimental chemistry, which numbered amongst its members Sir Humphrey Davy, Gay-Lussac, Thenard, Berzelius, Kirwan, and Wollaston. Trained in the laboratory of the Royal Institution, then the great centre of attraction to Europe, he acquired habits of sound thought and philosophical methods of experimenting; and, as a careful and patient investigator and teacher of the great truths of chemical science, he conferred large and lasting benefit upon society. Davy's contributions to scientific literature are numerous, and are to be found in the Transactions of the Royal Society, and of various other learned bodies both in England and Ireland, especially of the institution of which he was so long professor.—J. F. W.  DAVY,, was born at Penzance in Cornwall, December 17, 1778. His father was a carver in wood. He does not appear to have been fortunately placed at school in the first instance; but he was afterwards, until he was fifteen years of age, with Dr. Cardew, whose school he quitted in 1793, and where he made great progress in the ordinary branches of knowledge, but certainly gave no indication of his future eminence. In 1795 he was apprenticed to Mr. Borlase, a surgeon and apothecary at Penzance, after his father's death, which took place in 1794, when young Davy was about sixteen years of age. While with Mr. Borlase he studied very assiduously, not only the sciences peculiarly belonging to his profession, but also the languages, history, mathematics, &c. In 1798 he was considered competent by Dr. Beddoes to take charge of an establishment which he had founded at Bristol, under the name of the Pneumatic institution; at this time he was scarcely twenty years old. In the following year he published "Essays on Heat, Light, Respiration," and other subjects which were very remarkable, although the theories they contain were soon abandoned by the author as too speculative. In 1801 he published in one volume, 8vo, a work entitled "Researches, Chemical and Philosophical, chiefly concerning Nitrous Oxide and its Respiration," in which he detailed several very interesting experiments in which he himself had incurred great hazard to life in the inhalation of various gases. During this year Davy came to London, and on the 25th April gave his first lecture at the Royal Institution. He began with the history of galvanism, detailed the successive discoveries, and described the different methods of accumulating it; and on the 31st of May, 1802, he was appointed professor. From this time to the year 1807 a great variety of subjects attracted his attention, especially galvanism and electro-chemical science, the examination of astringent vegetable matter in connection with the art of tanning, and the analysis of rocks and minerals with relation to geology and agricultural chemistry. In November, 1807, he announced a most important and unexpected discovery, viz., the decomposition of the fixed alkalies by galvanism and the metallic nature of their bases, to which he gave the names of sodium and potassium. From the year 1808 to 1814 twelve papers were read by Davy before the Royal Society, and published in their Transactions, all containing most important chemical and electrochemical discoveries and original researches. In 1810 he published the first volume of his "Elements of Chemical Philosophy," which, however, was never completed. His "Elements of Agricultural Chemistry" appeared soon after, and contains much useful matter; it is full of sound and practical views on the subject discussed. One of Humphrey Davy's greatest inventions, and with which his name is popularly associated, is that of the miners' safety lamp, the first paper in relation to which appeared in the Philosophical Transactions for 1815, and the last in 1817. Davy became president of the Royal Society in 1820, and contributed papers of great interest for some years. He was intimately associated with chemists and learned men of other countries, and it is a singular fact, that at the time when England and France were at war, he received in the handwriting of the Emperor Napoleon a free passage into and through France, at a time when all other Englishmen were denied admission into that country. It was during this time, when assembled in council with the savants of Paris, that he made his great discovery as to the nature and properties of iodine. On the 8th of April, 1812, Sir Humphrey Davy received his knighthood, and on the 11th of the same month he married Mrs. Apreece, the widow of Shuckburgh Apreece, Esq., and daughter and heiress of Charles Kerr, Esq., of Kelso, with whom he had a considerable fortune. It was the happy lot of Sir Humphrey Davy's mother to witness the realization of all her hopes for her son's future, and to see him receive at the hands of his own sovereign, and those of foreign countries, as well as from the most distinguished body of scientific men living, such honours as are accorded to but few of the votaries of science. He died on the 28th of May, 1829, at Geneva. His widow survived him until 1855. There are several lives of this distinguished man published—one by Dr. Paris, late president of the College of Physicians, which contains a perfect list of his works; one by his brother. Dr. John Davy; and one by the late Dr. Henry, from which we quote a few lines. In characterizing Davy he says, "His imagination, in the highest degree fertile and inventive, took a rapid and extensive range in the pursuit of conjectural analogies, which he submitted to close and patient comparison with known facts, and tried by an appeal to ingenious and conclusive experiments. He was indued with the spirit, and was a master of the inductive logic; and he has left us some of the noblest examples of the efficacy of that great instrument of human reason in the discovery of truth. He applied it not only to connect classes of facts of more limited extent and importance, but to develope great and comprehensive laws which embrace phenomena that are almost universal to the natural world. In explaining these laws, he cast upon them the illumination of his own clear and vivid conception. He felt an intense admiration of the beauty, order, and harmony which are conspicuous in the perfect chemistry of nature; and he expressed these feelings with a force of eloquence which could issue only from a mind of the highest powers and finest sensibilities."—E. L.  * DAVY,, the brother and biographer of Sir Humphrey Davy, eminent as a chemist, geologist, and physiologist. Dr. Davy studied medicine at Edinburgh, and took his degree in that university in 1814. He entered the army as a surgeon, but latterly retired to Ambleside in Cumberland. He has written many works and papers on various subjects connected with natural science, and his physiological contributions to the Philosophical Transactions and the Transactions of the Royal Society of Edinburgh, are numerous. In 1839 he published two volumes entitled "Researches Physiological and Anatomical." They embrace a wide field of inquiry, and afford abundant evidence of a highly-cultivated mind. The subject of animal heat has been largely treated of by Dr. Davy, who, in all his observations, shows an intimate acquaintance with the science of chemistry. The titles of some of his papers will show the extensive range of his inquiries—"On the Specific Gravity of different parts of the Human Body;" "An account of some Experiments and Observations on the Torpedo;" "On the Early Generative Power of the Goat;" "On the Composition of the Colostrum;" "Miscellaneous Observations on Blood and Milk;" "On the Specific Gravity of certain substances considered lighter than water;" "On the Property belonging to Charcoal and Plumbago in fine Plates, of transmitting light." One of his latest works, published in 1849, is "Lectures on the Study of Chemistry in connection with the Atmosphere, the Earth, and the Ocean; and Discourses on Agriculture, with Introductions on the present state of the West Indies, and on the Agricultural Societies of Barbadoes.'"—E. L.  DAVY,, a celebrated English musician, was born at Upton Helion, near Exeter, in 1770, and died in 1824. When he was about three years of age, he came into the room where his uncle, who lived in the same parish, was playing a psalm tune on the violoncello; but the moment he heard the instrument he ran away crying, and was so much terrified that it was thought he would have gone into fits. For several weeks his uncle repeatedly tried to reconcile him to the instrument; and at last, after much enticement and coaxing, he effected it by taking the child's fingers, and making him strike the strings. The sound thus produced very much startled him at first; but in a few days he became so passionately fond of the amusement, that he took every opportunity of forming a better acquaintance with the monster which had before so much terrified him. About this time there happened to be a company of soldiers quartered at Crediton, a town about a mile from Helion. His uncle frequently took him there, and one day attending the rollcall, he appeared much pleased with the fifes. Not contented, however, with hearing, he borrowed one of them, and soon made out several tunes, which he played very decently. At the age of four or five years, his ear was so correct, that he could play an easy tune after once hearing it. Before he was quite six years old, a neighbouring blacksmith, into whose house he used 