This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1903 Excerpt: ...The liquid portion constitutes oleomargarine, whilst the solid is known as pressed tallow or tallow stearin. Tallow oil is another product obtained by expressing the more fluid portions of tallow at a lower temperature. The quality of tallow is determined by means of the 'titer' test (p. 48). According to Lewkowitsch ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1903 Excerpt: ...The liquid portion constitutes oleomargarine, whilst the solid is known as pressed tallow or tallow stearin. Tallow oil is another product obtained by expressing the more fluid portions of tallow at a lower temperature. The quality of tallow is determined by means of the 'titer' test (p. 48). According to Lewkowitsch Chemical Analysis of Oils, Fats, and Waxes), the ' titer' of tallow for use in the candle industry should not be below 44 C. Smetham recommends for general use, in evaluating tallow for the soap and candle manufactures, the determination of the iodine value; low iodine values correspond to the high ' titers.' The iodine value, which does not necessitate the isolation of a large quantity of fatty acids, is much more easily determined. Smetham (J.S.C.I., 1899, 330) gives the iodine values of about 1,000 samples of commercial tallows examined by him; 5 samples had values below 36; 47 between 36 and 40; 750 between 40 and 45; 180 between 45 and 50; and 21 between 50 and 57. Most of these samples were accepted as 'commercially pure.' The average iodine value of 592 samples of English tallow was 42-81. In order to eliminate the personal equation in performing the 'titer' test, Shukoff J.S.C.I., 1899, 406) employs a beaker-shaped vessel 3 cm. wide, narrowed towards the top and fused into a larger glass vessel 5 cm. wide and 10 cm. high; the space between is exhausted of air to a very high vacuum. The principle of Dewar's tubes is thus employed to prevent the escape of heat. Thirty to forty grms. of the melted fatty acids are poured into the apparatus, a cork carrying a delicate thermometer is inserted, and when the temperature has sunk to within 3 of the expected solidifying point the apparatus is shaken steadily until the contents become decidedly tu...
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