308 SORGHUM. 



Bisulphite of Lime. 



This compound, so called, exists neithei in theory nor in practice; but 

 the name has long been applied to the salt produced by the union of. 

 lime and sulphurous acid, the only chemical compound of which is the 

 sulphite of lime known commercially as the bisulphite. It may be 

 had in quantity at a few cents (five to seven) per pound, and contains 

 about 30 per cent of sulphurous acid (if chemically pure, it should con- 

 tain 53g- per cent), and, owing to its comparatively low price and great 

 convenience in handling, is the most available form in which sul- 

 phurous acid may be used by the sugar manufacturer. This salt is 

 practically insoluble in water; but is soluble in a solution of sulphurous 

 acid, and is said to exist in such soluti<m as the bisulphite, which in 

 effect it is, and in sucli solution it is largely prepared and used by 

 sugar makers. In using this re-agent in defecation, the acid of the juice 

 will liberate the sulphurous acid, and give j^ractically the same results 

 as by the use of the gas. 



Many experiments were made with a mixture of slaked lime and 

 commercial sulphite, using the same in precisely the manner of using the 

 lime in defecation. The mixture contained 15| per cent of sulphurous 

 acid, 50 per cent of dry slaked lime, and the remainder moisture, sul- 

 phate of lime, and other impurities. 



For comparison, certain experiments were made with the calcium 

 sulphite alone, and the results are given at the end of this chapter. 



EXPERIMENTS IN DEFECATION. 



During the season of 1882, there w^ere made, in all, seventy-eight 

 experiments in defecation, using the following re-agents: Hydrate of 

 lime, calcium sulphite, and a mixture of these two. The results of 

 these experiments are given in detail in the following tables: 



In table A, is giveji the variety of sorghum used in each experiment; 

 and it will be seen that the new African varieties were used in eight 

 of the experiments, the new varieties from India in five experiments, 

 and different varieties grown in this country for the remaining sixty- 

 five experiments. In each case, for purpose of comparison, the analy- 

 sis of the juices is given. In most cases, each sample of juice analyzed 

 was used for several experiments in defecation, and the syrups, in each 

 case, were also analyzed. 



In Table B, the details of each experiment is given, and the charac- 

 ter of the different syrups produced. 



In Table C, are given details of fourteen experiments in defecation 



