200 TlMEHRl. 
fuel, and with which the other samples can be correctly compared, the 
constituents of the megass are given in percentages of the original 
weight of canes, so that the actual amounts are carried right through, 
and I include the water of crystallization a no unimportant portion of 
the total self-contained water that appropriates so many units of heat, and 
detracts from the value of the megass as a useful agent. The number 
of units of heat per pound of carbon (13*009) is practically the same as 
that employed by Mr. Alexander, and the number convertible into work, 
in practice, I take at 56 per cent of the theoretical figure, because I find 
this to be a mean of a number of trials given in Clark's " Rules, Tables 
and Data." 
There is a striking similarity between the percentage of expression 
upon the maximum possible and the relative value of the megass as a 
fuel, so much so that one might consider the value of megass obtained 
from such canes as proportionate to the percentage of expression ; these 
figures, however, do not represent a correct comparison, except on the 
assumption that combustion is equally rapid and perfect in all cases, 
and as this can not be, I believe the megass from badly crushed canes is 
a far more inferior fuel than here represented. In other words, every 
step made toward heavier crushing and improved expression, will pro- 
duce a fuel exceeding in relative value that given in the last column of 
the table. 
Curiously enough, the megass from 67 per cent, expression carries 50 
per cent, water, and its relative value as a fuel is 78, precisely the same 
figure as given in my previous paper for megass holding the same 
percentage of moisture. 
Mr. Russell attributes to superior crushing the surplus of carbon and 
a diminution of water in " Leonora" megass as against "Rose Hall," 
how can any comparison be made when the canes are so dissimilar ? 
The less a cane is crushed the more must be the water left in its me- 
gass, as well as more carbon, the excess of which (with ordinary good 
canes,) is theoretically equivalent to the evaporation of the excess of 
water, but as in practice only about 56 per cent, of the heat units are 
convertible into work, the excess of water predominates, and if " Leo- 
nora" canes had been ground at " Rose-Hall," the megass would have 
been inferior, although carrying more carbon, as distinctly illustrated 
by the above tables. 
Then again from actual experiments made with green and logie 
megass, Mr. Russell arrives at certain conclusions which I propose to 
