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MEGASS AS FUEL.as the cellulose, it is possible to calculate the thermal value of a megass; thus,a megass of composition fibre, 42 per cent., sugar, 9.666 per cent., will afford,on complete combustion, .42 x 7533 + .0966 X 7120 = 3851 B.T.U. per lb.for the fibre and sugar alone, to which must be added that due to the glucoseand other organic matter; if this be taken as 1/10 that due to the sugar, thegross thermal value of the megass will be 3920 B.T.U., and per unit of drymatter, supposing the megass contains 47 per cent. of water, 7396 B.T.U.The heat of combustion of megass of different origin has been experimentallydetermined by a number of workers. Geerligs 4 , whose results are discussedmore fully in another section, found the heat of combustion, per lb. of drymatter, to be sensibly constant; his extreme values in B.T.U. are 8249 and8514, with a mean of 8381; Burwell 5 , in Louisiana, obtained a mean value of8325, with extremes of 8289 and 8384. These values are considerably higherthan would be obtained on calculation on the lines exemplified above ; actually,then, it will be sufficient, under average conditions, to accept a fixed value of8350 B.T.U. per lb. of dry matter in a megass.Products of Combustion of a Megass.—Each pound of carbonon combustion requires a theoretical minimum of 2.67 lbs. oxygen, a quantitysupplied by 12.03 lbs. of air, the remainder, 9.36 lbs., being nearly all nitrogen;at a temperature of 84° F. this quantity of air occupies 165 cubic feet. Thecombustible elements in megass contain hydrogen and oxygen in the same proportionthat they exist in water, so that in calculating the air required forcombustion only the carbon need be taken into account. Of the bodiespresent in megass, cellulose contains 44.4 per cent., xylan 45.4 per cent.,sugar 42.1 per cent., and glucose 40.0 per cent. of carbon, so that from theanalysis of a megass its carbon content can be found. In actual determinationsGeerligs found megass to contain from 46.82 per cent. to 48.45 per cent.carbon, and from 6.30 per cent. to 6.67 per cent. hydrogen on the dry ash freematerial; as an average then, per lb. of dry matter, a megass may be takenas containing 46-5 per cent. of carbon, and 6.5 per cent. of hydrogen, allowingthat the dry matter contains 2 per cent. of ash.Per lb. of dry matter, then, the products of combustion of a megass will beDue to carbon .465 X 44 = 1.70S lbs. carbon dioxide.12Due to hydrogen .065 X 18 = .585 lbs. water.2Due to nitrogen of air .465 x 9.36 = 4.352 lbs. nitrogen.Fuel Value of Megass as influenced by Variety.—In"Sugar and the Sugar Cane" (page 280) it was stated that it was a matter ofclinical observation that the megass from different varieties of canes exhibitedvery different values as fuel, and that this difference could not be accounted for bylow fibre content of the cane or yet from the analysis of the megass. Similar411