TRANSACTIONS OF THE SECTIONS, 61 
juice in the cane, and sugar in the juice, I have lately gone through a series of ex- 
periments having for their object the settlement of the doubt, and with the result of 
amply confirming the testimony of other experimenters. Having operated on canes 
from various parts of this district by slicing them, exhausting first by hot water, then 
by hot alcohol, and finally drying, I obtained as my mean result about 10 per cent. of 
woody or insoluble matter, whilst the sugar extracted and crystallized ranged from 
17 to 23 per cent., as had previously been stated. It would consequently appear that 
40 per cent. of juice is actually lost in the practice of our West India workings; and 
now arises as a most important consideration, the question as to what extent this loss 
is inevitable, and to what extent it might have been obviated by altered machinery or 
improved manipulation. 
Instead of 50 per cent. of juice extracted, 70 per cent. is much nearer the average 
amount yielded by the sugar-mills of this coast, although occasionally the result is as 
high as 75 per cent., and this in some cases with mills of very inferior construction. 
The cane however is passed between the rollers of the mill four times, until the refuse 
or megass, as the pressed cane is called, has been reduced to a state of disaggregation 
resembling ground tan, whereas the West India cane refuse is represented to be in 
the form of long strings, a sufficient proof that the pressure applied has been very 
inadequate. 
After the cane has finally left the mill, it is immediately, in the Spanish sugar re- 
gions, subjected to the operation. of pressing, sometimes by the agency of a screw, but 
in many cases by hydrostatic force. By the latter method I have seen 13 per cent. 
of juice extracted from megass which had already yielded up 73 per cent. of juice to 
the mill, thus elevating the total quantity extracted to 86 per cent. out of the original 
90, and consequently, as a manufacturing operation, leaving very little more to be 
desired. The hydrostatic press I consider to be an apparatus which is indispensable 
to the ceconomy of every sugar estate: not only does it largely contribute to the 
amount of juice extracted, but what is most remarkable, the juice resulting from hy- 
drostatic pressure of megass, is invariably, so far as my observations have gone, richer 
in sugar than juice yielded by the mill, a fact which seems to be only explicable on 
the supposition that the hydrostatic press, in virtue of its great power, is enabled to 
extrude those particles of sugar which microscopic examination demonstrates to exist 
in the cane in the solid and crystalline form. 
The subsequent stages of the sugar manufacture, as carried on in Spain, do not 
materially differ from those in operation in Cuba and many other tropical countries. 
The juice is defecated or purified by lime, skimmed, evaporated to the requisite de- 
gree, and poured into earthenware moulds, the contents of which are finally exposed 
to the operation of claying. In one manufactory, however, witnessed by me, at 
Almunecar, lime is no longer used, on account of its well-known injurious effects on 
sugar, no other agent having been substituted in its stead, but sole reliance being 
placed on the coagulation by heat of albuminous matters present in the juice, and 
their final removal by skimming. Under this system of manufacture, the sugar pro- 
duced is light-coloured but badly grained, and the unseparated albuminous matters 
are present in such quantity, that every 103 parts of the concentrated saccharine 
juice, as it comes from the teache or last evaporating pan, only yields 40 parts of 
crystallized sugar on cooling, the other 60 per cent. remaining in the condition of 
molasses, perfectly uncrystallizable until some adequate means for defecation be had 
recourse to. 
The chief object of my residence in this sugar district was to superintend the erec- 
tion of machinery for manufacturing sugar by means of my own process. ‘The site 
of our operations is Motril, about forty-five miles south of Granada, in a manufactory 
furnished with apparatus of the rudest character, Up to this period (July 9th), our 
own vacuum apparatus has not been sufficiently advanced to enable us to pursue our 
operations by its aid; nevertheless, owing to the superior defecating power of the sub- 
acetate of lead, we have, even with the old and rude machinery, obtained a result of 
more than 16 instead of 7 per cent. ofsugar. Our striking teaches or final evaporating 
pans we were under the necessity of removing, in order to afford the requisite space 
for our own machinery; hence we were reduced to the necessity of concluding our 
process of concentration in a brass pan of conical form and holding about 600 imperial 
gallons, thus materially increasing the difficulty of the evaporative process.. Hitherto 
only one-sixth per cent., on the juice, of subacetate has been used, but I imagine the 
