Page:Popular Science Monthly Volume 25.djvu/647

Rh Accordingly, in 1878, the work was commenced by Professor Peter Collier, Chemist of the Agricultural Department, at Washington, and his investigations were continued through the years 1879 to 1882, inclusive.

One of the principal objects of this work was the determination of the precise quality of sorghum-juices at different periods in the development of the plant, in order to show at what stage the greatest amount of available sugar was present in the juice. It was shown, by thousands of analyses, that fully-matured plants yielded the greatest amount of sugar, and that the period during which this amount was maintained was full three months for some of the varieties which matured most rapidly.

It was shown that some kinds of sorghum matured quickly, and were well adapted to the short, hot summer season of the Northern States, while other varieties ripened more slowly, and were best adapted for cultivation in the Southern States.

It was demonstrated also that, when mature, the best of the different varieties were practically identical as regards the percentage of available sugar in the juice.

The amount of crystallizable sugar in the juice of mature sorghum varies between fourteen and sixteen per cent; there are also present about one to two per cent of uncrystallizable sugar ("glucose"), and two to three per cent of other solids, part of which are removed from the juice by the purifying processes employed in sugar-making. When well purified, sorghum, cane, and beet sugar are identical in composition and properties.

Among other valuable data obtained during these investigations, were recorded the length of time, after seeding, before the plant reached maturity; the length of the period during which the juice contained a profitable amount of available sugar (i.e., the "working period"); the height, weight, and percentage of juice for the stalks of each variety of sorghum at each stage in its development; and numerous other facts of importance to the practical sugar-maker.

The utilization of waste, or by-products, was carefully considered. It was shown that sorghum-seed is very similar in composition and food-value to common Indian corn, and that the yield of twenty or more bushels per acre will nearly or quite repay the farmer the cost of cultivation. This seed has been successfully used for fattening cattle and swine.

It was shown that the apparently worthless skimmings obtained in the clarification of the juice had a value as fertilizing material, and that from the washings of the tanks and evaporators a considerable amount of pure alcohol or vinegar could be produced at small cost.

The crushed canes ("begasse"), after the removal of the juice, make paper-stock of excellent quality and medium length of fiber. This begasse may be preserved as food for cattle by the method known