MANUAL FOR SUGAR GROWERS. 81 



How important good crusliing is to the planter 

 will be seen in a moment from the following figures : 

 If one mill expresses 55 per cent, and another 70 

 per cent, from the same canes, then the gain is fif- 

 teen on every fifty-five, or 26.1 per cent. The aver- 

 age expression of Avhat are regarded as fairly good 

 mills in the Leeward Islands is probably not over 

 60 per cent. ; the possible expression is certainly 

 not under 75 per cent. ; in other words, over 25 per 

 cent, of the sugar now grown, and which with good 

 machinery could be extracted, is at present thrown 

 away. It is evident that this condition cannot last 

 in these days of keen competition. 



In large factories it is the practice to resort to 

 double or even triple crushing ; two or three mills 

 are arranged one behind the other, the canes being 

 thus submitted to two or three grindings. It is 

 usual to blow steam into the megass in its passage 

 from one mill to the other ; by this means the ex- 

 traction of sugar is increased. This would appear 

 to be due to two causes : one, the dilution of the 

 cane-juice, and the remaining moisture therefore 

 containing less sugar ; the second, that the cooking 

 resulting from the use of steam or hot water coagu- 

 lates the albuminous matter of the cane, and thus 

 facilitates the expression of the juice. 



It may be worth Avhile briefly to sketch out here 

 the principles on which the diffusion process of 

 extracting sugar from the cane is based. Those who 

 are interested in the practical application of the 

 process will find abundant information in the cur- 

 rent literature of the sugar industry, as in the 



