The Diffusion Process. 6i 
the artificial juice : so that the total quantity of heat is in- 
creased in the ratio of 1 13 to 126, or 1 1£ per cent, increase. 
M. ROBERT avoids this loss by first heating his slices by 
steam to the boiling point before they enter the battery. 
The diffusing water enters cold, and gradually takes up 
from the slices not only their sugar, but their heat, on 
the principle of regeneration, familiar to every engineer. 
Thus the slices leave the battery cold, while the artifi- 
cial juice leaves it hot. I may mention incidentally 
that I have found this analogy of regeneration most use- 
ful, in explaining the principle of diffusion to those who 
did not at first grasp it. Diffusion, you perceive, is the 
regeneration of sugar. 
I consider the maintenance of a high temperature 
throughout the battery so important, on account of the 
rapidity and thoroughness of extraction, and the preser- 
vation of the juice, that the economy in coal should be 
made subordinate to it. 
Fresh Water. — We require 1,900 gallons of pure 
water per hhd. of sugar made. Trench water will not 
do ; where is this enormous quantity of pure fresh water 
to be obtained ? This is the final question asked by the 
opponents of diffusion, in the certainty that it cannot 
be answered. Now see how simple the answer is. 
I stipulate for all evaporation being effected by steam- 
This should be done whether we grind or diffuse our canes; 
but with diffusion it is a sine qua non ; the teache, that relic 
of the barbarism ot the middle ages, must occupy no place 
in the boiling house. Now ev^ry physicist knows that 
when any weight of water is evaporated by saturated 
steam, an equal weight of that steam must be condensed. 
Therefore the condensed water resulting from the con- 
