QN THE JUICE OF THE SUGAR-CANE. 299 
pends essentially on the manner the pressure is exerted, and as often as 
the pressure is not regularly applied, the most powerful machines in 
present use, fail in one of their advantages, namely, to crush daily a 
greater quantity of cane. 
"We may seem perhaps rather indisposed to admit that machines 
otherwise perfectly regulated do not sometimes produce, even with the 
aid of strong and expensive apparatus, a return equal, or at least hardly 
superior, to what is produced by mills of far less power. Every atten- 
tive observer who has visited the sugar manufactories of this colony, 
will allow the justice of such an observation ; he will be astonished to 
see how little care is bestowed on this part of the work, and on merely 
examining the bagasse (a) escaping from the cylinders, he will find that 
it is frequently impregnated with a quantity of sugar liquid equal to 
the half of that of the juice extracted. We must, however, add that a 
contrary practice exists in some establishments, and where the pressure 
is always suited to the power of the machinery employed. 
Averaged generally, the yield which is usually furnished by the best 
mills on the largest estates, is about 75 per cent, of the juice contained 
in the cane, or three-fourths of the liquid to be extracted. The quality 
of the canes experimented on, and the degree of resistance they offer 
naturally influence this estimate, the extreme limits of which, from my 
own experience, are 84 per cent, and 69 per cent. 
Of all canes, the Belloguet or purple Java cane, is the most easily 
crushed, and gives the greatest quantity of juice; after it, comes the 
Diard cane, the Otaheite cane, the Penang, the Guinghan, and the Bam- 
boo. 
The method employed to test what a mill can yield, consists in first 
weighing the canes to be crushed, and then in estimating the juice ob- 
tained from them, or determining the weight of the bagasse remaining. 
This method entails considerable trouble in weighing, on account of the 
enormous quantity of the substance employed, and does not present 
those conditions of exactness, which should accompany every experi- 
ment. For this reason we find considerable difference of estimation in 
those authors who have treated this question. 
I have adopted a much simpler method which allows us to under- 
take such researches without having occasion to keep an exact account 
of such large weights, and without being troubled with the quantity of 
canes employed. 
It will be sufficient to know by a preliminary experiment the quan- 
tity per cent, of ligneous substance contained in the canes submitted to 
the mill, the yield of which is required to be ascertained. This being 
once determined, we take a certain quantity of wet bagasse from the 
(a) The Creole corruption for an old Spanish term, implying the cane residuum 
alter passing through the mill. 
VOL. VI. I I 
