IHS SORftHUM. 



After the encouraging results of 1879, which have just been re- 

 corded, the examination of many other varieties of sorghum and maize 

 was continued at the Departmentof Agriculture in 1880, 1881, and 1S82, 

 including, in all, the examination of about 100 varieties of sorghum 

 and 20 varieties of maize, for the purpose of determining the nature 

 of certain changes going on during the life of the plant, and especially to 

 determine that period when, in each variety, the content of sugar was 

 at its maximum, as, also, to learn the length of time during which this 

 practical maximum was retained. 



To this end, the examinations were, in some instances, begun so 

 soon as a stem had fairly formed in the plant, in order to determine 

 how early in its life the presence of sugar could be detected ; and, in 

 all cases, the examinations were begun long before even the panicle 

 had appeared, and before any one would think to work the crop for 

 either sugar or syrup. These examinations were continued almost 

 daily with each variety, till long after frosts, and tlie results of each 

 variety were tabulated, and may be found in the Annual Reports of 

 the Department of Agricultui-e for those years. 



The interest and value which these results have, in giving, as they 

 do, in a condensed form, the life history of these plants, is such that 

 the detailed examinati(ms of three varieties is here given. 



The following tables show the results of the analyses of three varieties 

 of sorghum stalk;^, made during the season of 1881, at Washington, 

 D. C. — the date of each analysis, the dimensions and weight of the 

 stalk, the percentage of juice obtained from the stalk and the specific 

 gravity of the juice, the per cent of sucrose, glucose, and of the solids 

 not sucrose nor glucose present in the juice. In addition, there is 

 given the percentage of sucrose present, as determined by the polari- 

 scope, which will be found to correspond closely with the percentages 

 of sucrose as determined by analysis. 



An examination of these tables of analyses reveals the following 

 facts : In the earlier stages in the growth of each plant, the amount of 

 crystallizable sugar (sucrose) is small ; but, as the plant matures, the 

 sucrose rapidly increases until it equals from 12 to 16 per cent of the 

 juice. The " solids not sugar" in the juice also increase from the first, 

 but very much less rapidly than does the crystallizable sugar; at the 

 same time, the uncrystallizable sugar (glucose) steadily diminishes, so 

 that the purity of the juice (shown in the column marked "available 

 sugar"; increases constantly until the cane is ready to be worked. 



These facts, and the inferences to be drawn from tliem, will be more 

 fully discussed in connection with the general averages deduced from 

 these figures. See page 189. 



