[208] Journal of the American Chemical Society, Vol. 2, p. 399: Science, Oct. 1, 1881: Proceedings American Association for the Advancement of Science, 1881, p. 61: Sugar Cane, Vol. 13, p. 533, pp. 61-66. [209] Wiley and McElroy; Agricultural Science, Vol. 6, p. 57. [210] Chemical News, Vol. 46, p. 175. [211] Vid. op. cit, 14, p. 352. [212] Vid. op. et loc. cit., 41. [213] Vid. op. cit., 41, Vol. 65, p. 169. [214] Zeitschrift des Vereins für die Rübenzucker-Industrie, 1884, S. 854. [215] Bulletin 46, Division of Chemistry, U. S. Department of Agriculture, p. 60. [216] The Analyst, Vol. 20, p. 121. [217] Journal American Chemical Society, Vol. 15, p. 668. [218] Comptes rendus, Tome 118, p. 147. [219] Journal of the Chemical Society, Transactions, 1895, p. 735. [220] Die agrikultur-chemische Versuchsstation, Halle, a/S., S. 114. [221] Cellulose, p. 77. [222] Vid. op. cit., 46, p. 63. [223] Zeitschrift für physiologische Chemie, Band 13, S. 84. [224] Zeitschrift für angewandte Chemie, 1895, S. 561. [225] Vid. op. cit., 52, pp. 8 et seq. [226] Vid. op. cit. supra, p. 15. [227] Composition of Wood, Agricultural Science, Vol. 7, pp. 49, 97 and 161. [228] Tollens; Handbuch der Kohlenhydrate: von Lippmann; Chemie der Zuckerarten. PART FOURTH. FATS AND OILS. =277. Nomenclature.=—The terms fat and oil are often used interchangeably and it is difficult in all cases to limit definitely their application. The consistence of the substance at usual room temperatures may be regarded as a point of demarcation. The term fat, in this sense, is applied to glycerids which are solid or semi solid, and oil to those which are quite or approximately liquid. A further classification is found in the origin of the glycerids, and this gives rise to the groups known as animal or vegetable fats and oils. In this manual, in harmony with the practices mentioned above, the term fat will be used to designate an animal or vegetable glycerid which is solid, and the term oil one which is liquid at common room temperature, _viz._, about 20°. There are few animal oils, and few vegetable fats when judged by this standard, and it therefore happens that the term oil is almost synonymous with vegetable glycerid and fat with a glycerid of animal origin. Nearly related to the fats and oils is the group of bodies known as resins and waxes. This group of bodies, however, can be distinguished from the fats and oils by chemical characteristics. The waxes are ethers formed by the union of fatty acids and alcohols of the ethane, and perhaps also of the ethylene series.[229] This chemical difference is not easily expressed and the terms themselves often add confusion to the meaning, as for instance, japan wax is composed mostly of fats, and sperm oil is essentially a wax.