176 BOARD OF AGRICULTURE. 



practicall}' true. The specific gravit}' is represented by this line on 

 the chart. You see here it was 1031 water, being 1000. It runs 

 up graduall}'^ and gets up from 1031 to 1078, the average of the 197 

 determinations. Now what is this increase in specific gravit}' due 

 to? It is due to the fact that the juice expressed is becoming, as 

 the plants develop, richer and richer in soluble matter. \Yhat is the 

 soluble matter which increases its density? To a great extent it is 

 sucrose, that is crystallizble sugar. If that is so the curve that rep- 

 resents sucrose must closely correspond to the line that represents 

 the specific gravit3\ You will observe they follow ver}^ closely 

 along — here they cross. The sucrose increases a little more even 

 than the specific gravit}". The glucose runs down, and here are the 

 other solids in the juice which are not sugar, which does not 

 increase except towards the last, and it does increase then appreci- 

 ably. There is still another point, and that is what we call the 

 available sugar, and of course that is the practical point. I have 

 said nothing about syrups. The amount of sugar that can be 

 obtained from the saccharine juices depends upon two things. 

 Obviously it depends upon the amount of sugar that is in the juice ; 

 the more there is the more you can recover, other things being 

 equal. But it depends upon the amount of other things in the juice 

 besides sugar ; that is, the more of other things besides sugar that 

 are present, the less of the sugar that is present can be recovered, 

 because they will prevent the sugar from crystallizing. The avail- 

 able sugar in juice is determined by what is called the exponent ; 

 that is, it is the per cent, of sugar in the total solids ; for instance, 

 if one-half of the total solids in a juice is sugar, the exponent would 

 be fifty ; if three-fourths, the exponent would be seventy-five, and 

 so on. Now, if the experiment is sevent3'-five it means that seventy- 

 five per cent, of the sugar present can be recovered as sugar. So 

 that multiplying the per cent, of sugar present in the juice by the 

 exponent of that juice and we have a number representing the per 

 cent, of available sugar in the juice, and that curve on the chart is 

 represented b}- this line, which runs very low down. What is the 

 luimorical representation of that line? At this time the average 

 result of these thirty-eight varieties of sorghum show that there 

 were seventy-seven pounds of available sugar to the acre. Next, 

 one hundred eight3'-six pounds of available sugar. Next, two 

 hundred forty-eight pounds. Then, three hundred sixty-three. 

 Next, five hundred thirty-four. Next, six hundred seventy-four. 



