Page:The New International Encyclopædia 1st ed. v. 06.djvu/19

* DAVY. '( culture, and during ten years lectured before the Board of Agriculture on agricultural chem- istry. His lectures were published in 1S13, luider the 'title of Elements of AyiicuUurul Chemistry. The discoerie3, however, on which Davy's fame as a chemist chiefly rests, took their origin in the views which he developed in 180G in the Bakerian lecture, On Some Chemical Agencies of Electricity. This essay was universally regard- ed as one of the most valuable contributinns ever made to chemical science, and obtained the prize of the French Institute. According to Davy, chemical affinity is nothing but the mutual electrical attraction of the ultimate particles of matter, and chemical combination is caused by the equalization of electric potentials. Davy's electrolytic experiments led to the establish- ment on a firm scientific basis of Lavoisier's idea that bases are compounds of ox'gen with metals, and to the extension of this idea to caustic potash and soda, which Lavoisier had regarded as ele- ments. In 1S07 Davy succeeded in decomposing potash. When he first saw the globules of the new metal potassium, his delight is said to have been so ecstatic that it required some time for him to compose himself before he was able to continue the experiments. He next decomposed soda, strontia, and magnesia, and would have decomposed lime and baryta if be had not been prevented from doing so by a severe illness, dur- ing which those alkaline earths were decomposed by Berzelius and Pontin. In 1809 he demonstrat- ed the elementary nature of chlorine, and proved that hydrochloric acid is a compound of chlorine and hydrogen. It thus became clear that oxygen was not by any means an essential constituent of acids. In 1812 Davy was knighted, married a lady of considerable wealth, and resigned the chemical chair of the Royal Institution. That he might investigate his new theory of volcanic action, he received permission from the French Govern- ment — though the two countries were then at war — to visit the Continent, and was received with the greatest distinction by the scientifie men of France. On returning to England, in 1815, he entered on the investigation of the na- ture of fire-damp, which is the cause ot explo- sions in coal-mines. This resulted in the inven- tion of the safety lamp (q.v. ) — one of the most valuable presents ever made by science to hu- manity. Though the value of the invention was everywhere acknowledged, the only national re ward was a baronetcy after a lapse of three years. On the death of Sir Joseph Banks, in 1820, Sir Humphry Dav^- was elected presi- dent of the Royal Society. His attention was shortly after called to the important object of preserving the copper sheathing of vessels from corrosion by the action of sea-water. This he effected by means of bands of zinc; but the bot- toms of the vessels became so foul from the ad- hesion of weeds, shells, etc., that the plan hnd to be abandoned. Early in 1825 Sir Humphry Davy had begiui to complain of the loss of strength, and in 182C he had a paralytic attack affecting his right side. He made two journeys to the Continent for the reeoverv of his health, and died at Geneva on ]klay 29, 1829, at the early age of fifty-one. The Genevese Government evinced their respect by a public funeral. So widely spread was the repii- tation of Sir Humphry Davy that he was a mem- DAWES. her of almost all the scientific institutions in the world. Cuvier, in his Eloge, says: "Mr. Davy, not yet fifty -two years of age, occupied, in tlie opinion of all that could judge of such labors, the first rank among the chemists of this or of any other age." Besides works already men- tioned, and a great number of contributions to the Philosophical Transactions, Sir Humphry Davy published: Elements of Chemical J'hi- hjso'iihy (London-, 1812), and Salmonia, or Days of Fly-Fishing, published in 1827. His ConsoUi- tions in Travel, or the Last Days of a Philoso- pher i'Sd ed., London, 1831), appeared after his death. Consult: Memoirs of the Life of Sir Humphry Dacy, by his brother (2 vols., London, 1S3G), and The Life of Sir Humphry Davy, by Dr. Paris (London, 1831 ) . See, also. Chemistry ; and Chemistry, Acrictltural. DAVY JONES'S LOCKER. A common phrase applied to the ocean as the grave of men drowned at sea. Da-y Jones is a sailor's familiar name lor a malignant sea-spirit, or for the devil. DAVY SAFETY LAMP. See Safety Lamp. DAW. See .Jackdaw. DAW, Sir John. A cowardly gull and butt in Jonson's Epicoeue. The wits, in the play, arrange a duel between him and Sir Amorous I.a-Foole, from which both are glad to escape with a score of kicks from their mockers. DAWAL'LA. A catfish (Agenciosus da- walla) found in the rivers of Guiana, and highly c^>tecmed as food. It is sometimes two and one- half feet long, and has a snout somewhat like that of a pike, but the mouth is furnished only with very minute teeth. The skin is destitute of scales, and the colors have that brightness so often seen in tropical fishes — green, brown, and carmine. DA WANT, da'vii.x'. Albert Pierre (1852—). A Freiuh painter, born in Paris. He was a pupil of Laurens, and both in color and composi- tion resembles his master. He first exhibited in 1ST9. with "Saint Thomas a Becket." Subse- quent pictures include modern works as well, such as •'. Choir of Bovs" ( 1888) . in the Luxem- bourg: "The End of "the JIass" (1890); and '•The Captive" (1896). One of his best his- torical pictures is "The Emperor Henry IV. of Germany Before Pope Gregory VII." (1880). He received a first-class medal at the Paris Exposi- tion in 1889. DAWES, daz. Charles G.tes (18G5— ). An American civil engineer, lawyer, and politician, born at ilarietta.Ohio. He graduated in 1884 at ilarietta College, and in 1880 at the Cincin- nati Law School, became chief engineer of an Ohio railway, and practiced law at Lincoln, Neb., in 1887-94. He was a leader in the Mc- Kinlev movement in Illinois which resulted in instructions for McKinley at the Springfield (III.) Convention of April," 1896. He was Coni])- troller of the Currency from 1897 to 1901. He published The Banl^ing System of the United States (1894). DAWES, He.xry Laurens i 1816-19113). Au American politician, biuii in Cummingtou. Mass. He graduated at Yale in 1839. engaged in news- paper work for a time, studied law, and in 1842 was admitted to the bar. He was a member of the Massachusetts Legislature from 1S48 to 1852, and was United States district attorney