CHEMICAL COMPOSITION OF SORGHOI. 251 



rarely as high as 60 per ceiit, often not over 45 per cent, of the weight 

 of the stalk pressed. It is clear, therefore, that there is a loss of 

 from oue-third to one-half of the juice, aud approximately the same 

 loss of the sugar present in the cane. 



The extent of this loss is such, that it will be more fully discussed in 

 the chapter on " Waste products," page 376. 



Character and Composition of Sorghum Juice— Chemical Changes in Sugar 



Making. 

 In order that the sugar boiler may understand the nature of this 

 operation, aud the character of the problem to be solved in defecation, 

 as also to assist those who may desire to experiment for themselves in 

 an effort to improve the present method, the following statement as to 

 the character and chemical composition of the juice of sorghum is 

 given, as also an account of certain of the chemical changes to which 

 it is subject under certain conditions which naturally would exist in 

 the ordinary operations of sugar making. 



Sorghum Juice. 



The juice expressed fiom the sorghum at or near maturity is a liquid 

 containing quite a large amount of suspended jnatter, giving it a color 

 varying from green to a deep brown. This suspended matter is depos- 

 ited to a greater or less extent on standing, and consists of very fine 

 starch granules, colored violet blue by iodine, aud easily discolored by 

 the acids of the juice, fiber, and albumen, Avith the green coloring 

 matter of the outer portions of the stalk, aud sometimes a red coloring 

 matter i'rom the center of the stalk. 



After allowing it to settle a few minutes, it has a specific gravity of 

 from 1.06 to 1.09, and contains in solution, in addition to the substances 

 in suspensicm, most j^rominently sucrose, with smaller amounts of glu- 

 cose, aconitic acid, soluble albumen, amide bodies, and inorganic salts. 

 It can be freed fi*om albumen, organic, and some inorganic acids, by 

 means of basic acetate of lead — and this method of defecation is in use 

 in most laboratories in the analytical determination of the content of 

 sugar in the cane. The filtrate, after the addition of the acetate of 

 lead, contains in addition to the sugars nothing which reduces Feli- 

 ling's copper solution, with the exception possibly of a very small 

 amount of amide substances. 



The fallowing examination of a juice collected on November 2nd, 

 1881, though somewhat late in the season and after a slight frost, will 

 illustrate some points in the general composition : 



