172 TlMEHRI. 
carbon present in the cane with the carbon present in coal and 
as Mr. Russell states, it ought^ to evaporate almost twice the 
water contained in the cane. But it is a known fact, that this 
is not the case, as the cane cannot be made to burn. The rate of com- 
bustion is greatly influenced by the presence of moisture in the fuel 
and consequently fuels containing largely differing quantities of mois- 
ture cannot be compared with each other, by taking their total heat 
of combustion in units of heat. The rate of combustion varies as some 
function of the moisture. This function may be determined, by making 
a series of experiments with megass, containing different quantities of 
moisture. Mr. Russell has found from his experiments with green 
megass, that 6'4 fts. of water are evaporated by i lb. of carbon, the crush- 
ing being 70 per cent., and the megass burnt in Coster's Furnace. By sub- 
stituting 37"3 per cent, the available carbon in sugar for 42' 1 in Mr. 
Russell's figures, 6'4 becomes 6'5 lbs. of water evaporated per pound of 
carbon. Let us call this quantity the co-efficient of evaporation of 70 
per cent, crushing megass. The co-efficients for the different kinds of 
megass can be obtained by making them proportional to the tempera- 
ture of their products of combustion. It is not intended to convey the 
impression that these co-efficients are the actual figures. To obtain 
these would necessitate a series of carefully made experiments ; besides 
they would vary for different furnaces, but as they appear to approach 
very nearly the conditions of practice, they have been used in the discus- 
sion of the value of the different kinds of megass as fuel. By deducting 
the amount of water contained in any megass from the product of this 
co-efficient and the available carbon in the megass, we obtain the 
quantity of feed water, which can be evaporated by the megass. 
After having explained the figures found in the table, we shall now 
proceed to their discussion. An examination of these figures will show 
that as the crushing is improved, the quantity of the water in the megass 
diminishes in more and more rapid ratio. The fibre increases in the 
same ratio as the water decreases and there is no doubt, but what the 
great increase of power necessary to improve the crushing bears some 
ratio to the fibre present in the megass. By comparing megass of 65, 
70 or 75 0/0 crushing with logie-dried megass, it will be seen that there 
cannot possibly be any saving of fuel by burning green megass. The 
megass, after being logie-dried has lost its sugar by decomposition, but 
the water lost by evaporation, more than makes up for this loss of 
sugar, as we shall see presently : — 100 lbs. of 65 0/0 crushing = 44 , 5 lbs. 
