CANE SUGAR. 



observations have apparently been made in Java, and the matter has been 

 exhaustively enquired into by Geerligs 4 , a summary of whose results is given 

 below. 



1. Actual determinations of the thermal value of the megass from 

 different canes showed that the calorific value calculated to dry weight varied 

 but little, and that the differences were entirely insufficient to account for the 

 variation experienced in factory work. Of the samples examined by him the 

 calories per kilogram of dry megass varied from 4583 to 4700. 



2. The elementary composition of the ash free megass from different 

 canes was determined, and those examined were found to give nearly identical 

 results ; expressed as per cents, of the dry ash free material, the megass con- 

 tained from 46-82 per cent, to 48-45 per cent, carbon, from 6-30 per cent, to 

 6-67 per cent, hydrogen, from 44-94 per cent, to 46-43 per cent, oxygen, and 

 from -14 per cent, to *18 per cent, nitrogen. 



3. It was supposed that the fibre from the softer varieties of cane might 

 contain more pentosans and xylan than that derived from the harder varieties, 

 but the differences found were quite insignificant. 



4. Differences in the cellulose content of the fibre were insufficient to 

 account for the observed variation in fuel value, although as a general rule a 

 cane rich in cellulose affords a satisfactory megass as fuel. 



5. Differences in the silica content of the samples examined were trifling, 

 and insufficient to account for the variations observed in practice ; it was 

 thought that perhaps a large quantity of easily fusible ash might coat the 

 megass and prevent its combustion, or might choke the air inlets between the 

 fire bars. 



6. Great variation was observed in the volume occupied by the same 

 weights of the megass from different varieties ; the weight of 100 c c. of 

 megass varied from 5-45 grms. to 7*95 grms., and the following observations 

 were drawn : 



a. The denser megasses were of superior fuel value. 



I. The denser megasses are generally rich in cellulose. 



c. Canes containing most fibre also give a megass of superior fuel 



value. 



Looked at in the light of these determinations, the question of the fuel 

 value of a megass is reduced to one of the mechanical structure of the fibre ; 

 a megass of low apparent specific gravity will thus occupy a large volume per 

 unit of weight ; the volume of megass which can be held on the grate of a 

 furnace is limited, and with the megass of low density it may happen that the 

 supply of fuel fed to the furnace is not sufficient to maintain steam for the 

 factory's needs ; when a different type of megass is being fired, owing to its 

 greater apparent specific gravity a greater weight is contained on the grate 

 without any change in volume, and steam is kept up without difficulty. 



412 



