82 TiMEHRI. 



ferment. The ultimate density of A. would be 986"8 

 while that of B. would be 987'4, and the return of A, 

 per 5 deg. of attenuation would be i.ig gallons of proof 

 spirit (standard), and for B. 1.13, or a return of 17.45 

 per cent, proof spirit for A, and 16.74 per cent, for B. 



This difference in the theoretical maximum is of 

 importance. To legislate with such divergence in the 

 standards, not to speak of the uncertainties, would at 

 least be confli6ting. One way by which to avoid this, 

 would be to calculate all sucrose into glucose and take 

 the increased density as the true original density. The 

 theoretical maximum would then be 1.13, and the govern- 

 ment requirements 66.37 P^'^ cent, of the theoretical 

 maximum. This figure seems a very fair one, and one 

 that should be very easily attained : and yet, in pra6lice, 

 during careful working, it has barely been reached. 



In pra6lice, as before stated, it is usual to allow the 

 fermentation to proceed spontaneously. The addition 

 of sulphuric acid or ammonia sulphate does not in the 

 least start the fermentation. They may, or may not, 

 improve the wash and make it a more suitable medium for 

 the development of the yeast, but unless yeast in some 

 way gets added, the addition of any quantity of these 

 bodies can be of no use in starting fermentation. 

 During grinding operations little trouble is found in 

 starting fermentation through the addition, one way or 

 the other, of the highly fermentable washings and scums ; 

 but if distillation has to be conduced by itself, after a 

 period of rest, the trouble in starting a good fermentation 

 and the low results, will no doubt be remembered by any 

 one who has had to deal with it. To find the reason of 

 this we must consider what fermentation is. 



