ON THE JUICE OF THE SUGAR-CANE. 245 
constitution of the saccharine crystal, can only be removed by the pro- 
cess of washing by the centrifugal machine. 
The presence of these corpuscles in a notable quantity gives a ready 
explanation of the difficulty experienced in turning out a white and 
brilliant sugar when the clarifying material, introduced too soon into 
the vacuum apparatus, has not been able to undergo sufficient cleansing 
in the open air. This, for instance, is what occurs in the so-called 
il triple effect apparatus," in which the juice is enclosed after defecation, 
a process inevitably incomplete according to the present method. 
The method which might be based on the particularities which I 
have just described is, in my opinion, one of easy application to all our 
sugar-machines, and would prove a powerful auxiliary to' the triple 
effect apparatus, which, for the reasons I have mentioned, is unable to 
produce a sugar of fine quality under the ordinary conditions in which 
the sugar manufacture of the colony is forced to proceed. The applica- 
tion of this method would merely require niters the shape of pails, fur- 
nished with a set of metallic cloths placed over each other by means of 
moveable frames, terminating in a plate pierced with holes, covered 
with one or two layers of flannel. The cane-juice as it flowed from the 
mill would at once receive that dose of lime necessary for the quality of 
the sugar to be produced, and would then rapidly be raised to the boil- 
ing point, and immediately after be thrown on the niters arranged in 
such a manner as to allow of a quick and perfect nitration. 
III. — Density. 
The density of cane-juice being one of its most easily determined 
properties, depending chiefly on the quantity of saccharine matter it 
contains, always attracted the attention of manufacturers, who even now 
do not have recourse to any other observation in oHer to specify the 
saccharine richness of the cane. But the clumsy and imperfect instru- 
ments w r hich are still employed for this purpose frequently render such 
determination quite illusory ; the error of which is still more increased 
by the circumstances under which they are made. Without taking into 
account the temperature and the aeration of the juice, as well as the 
organic remains which may be held in solution, a small glass instru- 
ment is introduced into the liquid which, generally speaking, has 
nothing in common with an areometer but the name and the form ; and 
it is from such indications that the saccharine richness of the juice of 
the canes passed through the mill is estimated. 
The density of cane-juice determined with care furnishes, however, 
valuable information, which being compared from month to month, and 
from year to year, may be made extremely useful in estimating the 
yield of canes manipulated under the same conditions ; it will even 
sometimes furnish a sufficiently precise idea of the definite result of a 
crop which has-been only begun. But in order to attain this end, it 
