lactic and acrylic series, and especially of certain important hydrocarbons, which were the immediate object of Frankland's search; these he called the 'alcohol-radicles,' believing them to constitute a series identical in composition, but isomeric, with the hydro-carbons of the marsh-gas series or 'hydrides of the alcohol radicles.' Carl Schorlemmer [q. v.] showed later that the two series of compounds were identical. In 1849 Frankland graduated Ph.D. in Marburg, and then went to work under Justus Liebig in Giessen. In 1850 he was elected to the professorship in chemistry at the Putney College for Civil Engineering, where he was a colleague of Playfair, and in 1851 to the professorship in the newly founded Owens College at Manchester. It was in Frankland's second paper on the organo-metallic compounds, read on 17 June 1852 before the Royal Society (Phil. Trans. 1852, p. 417), that he pointed out the 'general symmetry' of the formulæ of a number of inorganic and organic compounds, and suggested that 'the combining power of the attracting element ... is always satisfied by the same number of ... atoms,' and thus introduced into chemistry the conception of valency, completed later by Kekulé, A. S. Couper, and Cannizzaro (Frankland, Experimental Researches, p. 154), and now forming an integral part of the modern theory of organic .compounds. Frankland's theory passed without notice by the majority of chemists. Kolbe, however, after first rejecting them, was directly led by Frankland's suggestions to his theory of the relationships of organic acids, aldehydes, and alcohols, &c., which is of fundamental importance in the evolution of the subject. The two men published a joint paper on the question (which appeared by accident in Kolbe's name only") in Liebig's 'Annalen,' 1857, ci. 257, and this was followed by other papers by Kolbe. Frankland had already at Putney begun to work at applied chemistry. In 1851 he carried out an elaborate investigation on White's hydrocarbon process for the manufacture of gas, and in 1853 invented an argand burner, in which the 'regenerative' method of utilising heat that would otherwise be wasted a method originally devised and employed later on a manufacturing scale by Sir William Siemens [q. v.] found an early and probably independent application (Ure, Dict. of Arts and Manufactures, 4th ed. ii. 562). On 2 June 1853 Frankland was elected F.R.S., and in 1857 he received a royal medal from the Royal Society. In the same year he was elected lecturer on chemistry at St. Bartholomew's Hospital, London. On 3 March 1859 he read as the Bakerian lecture his fourth memoir 'On Organo-metallic Bodies.' In the summer of 1859 he was asked, together with Professor August Wilhelm Hofmann, to report to the metropolitan board of works on some means of deodorising sewage, which was then sent raw into the Thames, and had caused the river to become 'black and horribly offensive.' This was the beginning of Frankland's work on water analysis and water purification, which later absorbed a great part of his energies. On 20 Aug. 1859 Frankland and Tyndall ascended Mont Blanc, and were the first to spend a night on the summit (Experimental Researches, p. 867). Frankland showed that candles burnt at the same rate under low atmospheric pressure at the summit as at Chamonix, but gave out less light. These observations were the starting-point for an elaborate experimental investigation on the influence of atmospheric pressure on combustion (published in the years 1861 to 1868), in which he demonstrated the unexpected result that a oxyhydrogen flame may be made to give out a continuous spectrum. His experiments led him in 1867 to suggest that the luminosity of flames was due not to the presence of solid particles, as had been previously supposed by Sir Humphry Davy [q. v.], but to dense gaseous hydrocarbons. Frankland showed that change of temperature affected the "spectrum in the case of lithium, this being the first observation of the kind (Letter to Tyndall, 7 Nov. 1861, Phil. Mag. [4] xxii. 472), and made some further contributions to spectrum analysis (Proc. Roy. Soc. 1867 xvii. 288, 453, 1869 xviii. 79) in conjunction with (Sir) Norman Lockyer. On 4 May 1863 Frankland was elected to the chair of chemistry in the Royal Institution, which he retained till 1868. In 1865 he was elected as Hofmann's successor to the chair of chemistry in the Royal College of Chemistry, afterwards united with the Royal School of Mines. In the last of Frankland's more extensive researches on organic chemistry he described, in conjunction with Baldwin Francis Duppa, F.R.S. (obituary in Journ. Chem. Soc. 1874, p. 1199), a general synthetic method of first-rate importance for the production of a large variety of fatty acids by the use of 'carbo-ketonic ethers.' A preliminary investigation on the subject had been published shortly before by Geuther, but the independent researches of Frankland and Duppa cover much wider ground, and are regarded as classical (see Wislichnus in Liebig's Annalen, 1877, clxxxvi. 161). In 1866 Frankland proposed a new system of formulæ for organic compounds, but it
