Davy, Sir Humphry, 106; opposes the atomic theory, 129; accepts same, 130; studies the chemical aspects of electricity, 185; experiments on the acid and alkali said to be produced by electrolyzing water, 186; apparent suspension of chemical affinities by action of electricity, 191; discovers potassium, 197; and sodium, 198; the metallic bases of earths, 200; proves the elementary nature of chlorine, 202; Davy's birth and youth, 215; experiments on heat, 217; his work at Bristol, 218; inhales gases, 220; lectures at the Royal Institution, 222; discovers iodine and invents safety-lamp, 224; dies, 226. Dialysis, 247. Diffusion-rates of gases, 241; distinguished from transpiration-rates, 242; diffusion-rates of liquids, 245. Dulong, his law of atomic heat, 168. Dumas, Jean B. A., birth and education, 257; physiological studies, 258; meets Von Humboldt, 259; attacks the dualism of Berzelius, 260; Dumas's vapour density process, 262; ethers and alcohols, 265; chlorine in connection with organic compounds, 271; determines composition of chloral and chloroform, 273; studies fermentation, 287; member of the National Assembly, 288; takes office, 289. E Earths, 177; Stahl's views, 178; the connection between earths and alkalis, 178; their metallic bases, 182, 200. Economy of waste materials, 300. Electric affinity, 191, 210. Electricity, Volta's battery, 185; used to decompose water, 185; new metals discovered by its help, 197. Elements: old doctrine of elementary principles opposed by Boyle, 93; modern definition of element, 95 (_vide_ "Spectroscopic analysis"--basic lines, 311). Equivalency, conception of, 294. F Fermentation, studied by Dumas, 287. Fourcroy, calls Lavoisier's views "La chimie Francaise,", 95 G Gay-Lussac, 138, 143, 201, 203, 257. Gerhardt, 272, 279. Graham, Thomas, early life, 233; made Master of the Mint, 234; his death, 235; studies alcoates, 235; formulates conception of acids of different basicity, 237; considers hydrogen a metal, 238; investigates phenomena observed by Doebereiner, 240; diffusion-rates of gases, 241; of liquids, 245; his atmolyzer, 243; his dialyzer, 247; studies movements and reactions of molecules, 249. H Hales's experiments on gases, 34. Heat, Black's study of latent heat, 39; specific heat, 98; Dalton lectures on, 117; law of capacity for heat, 168; heat as produced by friction, 217. Helmholtz, 143; vortex atoms, 125. Hooke, Robert, his "Micographia," 24; studies combustion, 34. Humboldt, Alexander von, assists Liebig, 256; and Dumas, 259. Hydrochloric acid discovered by Priestley, 66; a stumbling-block to Lavoisierian chemists, 200; studied by Davy, 201. Hydrogen, rediscovered by Cavendish, 63; experimented on by Priestley, 66; its atomic weight decided by Dalton, 130; Graham considers it a metal, 238. I Iodine, discovered by Davy, 224. Isomerism, 297.