from Egyptian. The amount obtained was 0.90 per cent. Exposed to the air for several days it took up 19 per cent. of water. This extract contained 1.07 per cent. nitrogen. Towards Fehling's solution it behaves as a powerful reducing agent, and this fact may be of some importance in bleaching on the one hand and on the bleeding of certain fast colors (Indanthrene, etc.), in boiling with caustic alkalis. Aqueous Extract.-Darker in color than that obtained from Egyptian. The amount obtained was 1.61 per cent. Exposed to the air for two days it gained 9 per cent. in weight. It also reduced Fehling's solution, but not so powerfully as the alcoholic extract. The amount of nitrogen which it contains is 0.37 per cent. This extract shows an acid reaction to litmus. Ammonia Extract. Similar in appearance to that obtained from Egyptian. The amount obtained was 0.39 per cent. After evaporating to dryness it is only partially soluble in weak ammonia. The nitrogen was not estimated in this extract. Formic Acid Extract.—This extract was obtained by means of dilute formic acid (25 cc. formic acid per litre) and yielded 0.46 per cent. of a grayish-brown solid, which was not hygroscopic. It consists mainly of mineral matter. Hydrochloric Acid Extract.--This amounted to 9.43 per cent., and of all the extracts contained the highest percentage of nitrogen, viz., 9.8 per cent. This extract consists as would be expected largely of mineral matter. BENGAL COTTON. In this case only the crude wax was estimated, and this amounted as previously stated to 9.38 per cent. The portion soluble in petroleum spirit (Wax A) was of a clear orange color, while the residue (Wax B) consisted of an almost black friable mass. The results obtained are tabulated below for comparison. After the formic acid extraction the Texas cotton was further extracted cold for two hours with hydrochloric acid of 2° Tw., and the extract evaporated to dryness on the water bath, as in the previous cases. It amounted to 0.43 per cent. It will thus be seen that by purely mechanical solvents alone the amount of impurities extracted from Egyptian cotton was 2.67 per cent., and from Texas cotton 3.06 per cent., while further treatment by solvents which act chemically, although not drastic in their action, removed an additional 0.91 per cent. of impurities from Egyptian cotton and 1.11 per cent. from Texas cotton. Adding to the latter the 0.43 per cent. extract by hydrochloric, we have for Texas cotton 1.54 per cent. extracted by chemical means after the mechanical solvents employed had ceased to extract. Taking the total extract of the Texas cotton with the hydrochloric acid added, a grand total is obtained of 4.6 per cent., which is getting very near to the 5 per cent. usually supposed to be present. This figure must, however, be regarded as a more or less arbitrary one, and it is certain that some kinds of cotton contain more; in any case the loss in bleaching often considerably exceeds 5 per cent.-E. Knecht, Ph.D. |