54 IMPROVEMENTS IN THE REFINING OF SUGAR. 
Hitherto, in the manufacture of sugar from the cane, a 
very imperfect system of expression has been adopted, by 
which not more than one-half, or two-thirds at the most, of 
the juice is obtained. This portion is obliged to be rapidly 
evaporated, or fermentation would speedily commence, and 
much of the sugar is thus destroyed or rendered uncrystal- 
lizable. The part left in the cane might be extracted by 
means of water, but in tropical climates the tendency to fer- 
mentation precludes the possiblity of recovering the sugar 
from such dilute solutions. It may be considered, therefore, 
that not more than one-half of the sugar originally present 
in the cane is obtained in a good and saleable condition. 
M. Melsens recommends an entirely new method of pro- 
ceeding. The canes, instead of being merely crushed as 
heretofore, are rasped . About one per cent, of the solution 
of bisulphite of lime is now added, which prevents any 
change from taking place. The rasped canes are pressed, 
and water with a little of the bisulphite of lime is added to 
the marck, and the pressure repeated once or twice, so as 
completely to extract the sugar. The liquors thus obtained 
are, in the next place, heated to the boiling point, when 
coagulation lakes place, and the juice is thus defecated and 
decolorized. So completely unalterable is the solution 
said to be while there is any or the bisulphite present, that 
it is proposed to effect the evaporation spontaneously by the 
heat of the sun. The whole of the sugar is thus obtained, 
and nearly all of it in the crystallized state. — Pharmaceu- 
tical Journal for Nov. 
