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 probationary trial he was received into full connexion at the conference of 1831. For two years after this he remained at Brighton, and in 1833 he removed to Cornwall, being stationed successively at the Truro and Falmouth circuits. From Falmouth he removed to Darlaston, where in 1838 his health gave way. For a good many years he was a supernumerary, and lived for a while at Caen and Paris, where in the public libraries he found great facilities for prosecuting his favourite Oriental studies. His health having considerably improved, he became, in 1843, pastor of the Methodist church at Boulogne. He returned to England in 1847, and was appointed successively to the circuits of Islington, Bristol, Leeds, Penzance, Penryn, Truro and St Austell in east Cornwall. Shortly after his return to England he received the degree of Ph.D. from the university of Heidelberg. He was a patient, modest, hard-working and accurate scholar. He died at Camborne on the 24th of May 1866.

His principal works are Horae Aramaicae (1843); History, Liturgies and Literature of the Syrian Churches (1847); The Apostolic Acts and Epistles, from the Peshito or Ancient Syriac (1849); Jerusalem and Tiberias, a Survey of the Religious and Scholastic Learning of the Jews (1856); The Targums of Onkelos and Jonathan ben Uzziel (1st vol. in 1862, 2nd in 1865). See Memoir, by Rev. Thornley Smith (1871).

ETHERIDGE, ROBERT (1819–1903), English geologist and palaeontologist, was born at Ross, in Herefordshire, on the 3rd of December 1819. After an ordinary school education in his native town, he obtained employment in a business house in Bristol. There he devoted his spare time to natural history pursuits, and in 1850 was appointed curator of the museum attached to the Bristol Philosophical Institution. He also became lecturer on botany in the Bristol medical school. In 1857, through the influence of Sir Roderick I. Murchison, he was appointed to a post in the Museum of Practical Geology in London, and eventually became palaeontologist to the Geological Survey. In 1865 he assisted Prof. Huxley in the preparation of a Catalogue of Fossils in the Museum of Practical Geology. His chief work for many years was in naming the fossils collected during the progress of the Geological Survey, and in supplying the lists that were appended to numerous official memoirs. In this way he acquired an exceptional knowledge of British fossils, and he ultimately prepared an elaborate work entitled Fossils of the British Islands, Stratigraphically and Zoologically arranged. Only the first volume dealing with the Palaeozoic species was published (1888). Etheridge also was author of several papers on the Rhaetic Beds, and of an important essay on the Physical Structure of North Devon, and on the Palaeontological Value of the Devonian Fossils (1867). He edited, and in the main rewrote, the second part of a new edition of John Phillips’ Manual of Geology—entitled Stratigraphical Geology and Palaeontology (1885). He was elected F.R.S. in 1871, and was president of the Geological Society in 1881–1882. In 1881 Etheridge was transferred from the Geological Survey to the geological department of the British Museum, where he served as assistant keeper until 1891. He died at Chelsea, London, on the 18th of December 1903.

Memoir by Dr Henry Woodward (with list of works and portrait) in Geological Magazine, January 1904; also Memoir by H. B. Woodward (with portrait) in ''Proc. Bristol Nat. Soc.'' x. 175.

ETHERS, in organic chemistry, compounds of the general formula R·O·R′, where R, R′ = alkyl or aryl groups. They may be regarded as the anhydrides of the alcohols, being formed by elimination of one molecule of water from two molecules of the alcohols; those in which the two hydrocarbon radicals are similar are known as simple ethers, and those in which they are dissimilar as mixed ethers. They may be prepared by the action of concentrated sulphuric acid on the alcohols, alkyl sulphuric acids being first formed, which yield ethers on heating with alcohols. The process may be made a continuous one by running a thin stream of alcohol continually into the heated reaction mixture of alcohol and sulphuric acid. Benzene sulphonic acid has been used in place of sulphuric acid (F. Krafft, Ber., 1893, 26, p. 2829). A. W. Williamson (Ann., 1851, 77, p. 38; 1852, 81, p. 77) prepared ether by the action of sodium ethylate on ethyl iodide, and showed that all ethers must possess the structural formula given above (see also Brit. Assoc. Reports, 1850, p. 65). They may also be prepared by heating the alkyl halides with silver oxide.

The ethers are neutral volatile liquids (the first member, methyl ether, is a gas at ordinary temperature). Phosphorus pentachloride converts them into alkyl chlorides, a similar decomposition taking place when they are heated with the haloid acids. Nitric acid and chromic acid oxidize them in such a mariner that they yield the same products as the alcohols from which they are derived. With chlorine they yield substitution products.

Methyl ether, (CH3)2O, was first prepared by J. B. Dumas and E. Péligot (Ann. chim. phys., 1835, [2] 58, p. 19) by heating methyl alcohol with sulphuric acid. It is best prepared by heating methyl alcohol and sulphuric acid to 140° C. and leading the evolved gas into sulphuric acid. The sulphuric acid solution is then allowed to drop slowly into an equal volume of water, when the methyl ether is liberated (E. Erlenmeyer and A. Kriechbaumer, Ber., 1874, 7, p. 699). It is a pleasant-smelling gas, which burns when ignited, and may be condensed to a liquid which boils at 23.6° C. It is somewhat soluble in water and readily soluble in alcohol, and concentrated sulphuric acid. It combines with hydrochloric acid gas to form a compound (CH3)2O·HCl (C. Friedel, Comptes rendus, 1875, 81, p. 152). Methyl ethyl ether, CH3·O·C2H5, is prepared from methyl iodide and sodium ethylate, or from ethyl iodide and sodium methylate (A. W. Williamson, Ann., 1852, 81, p. 77). It is a liquid which boils at 10.8° C.

For diethyl ether see, and for methyl phenyl ether (anisole) and ethyl phenyl ether (phenetole) see.

ETHICS, the name generally given to the science of moral philosophy. The word “ethics” is derived from the Gr. , that which pertains to  , character.

For convenience in reference, the arrangement followed in this article may be explained at the outset:—