508 



Analysis of Sugar Cane. 



It yields a balsamic odour peculiar to the cane, and 

 which is so marked in raw colonial sugar. By filtration 

 through unsized paper it is obtained limpid, and has then a 

 very clear citrine tint, but whether opaque or transparent, it 

 undergoes no alteration by long exposure to air. 



Evaporated at a gentle heat after having been filtered, it 

 becomes a syrup, which placed in dry air, furnishes after 

 some days a hard, crumbling, colourless mass, and this mass 

 consists of crystalled sugar, almost pure. 



The analysis of this liquid is therefore remarkably simple, 

 for it consists merely in evaporating a given weight in a 

 capsule, which is again weighed when the substance has 

 become solid red, and quite dry. 



We arrive at the same end, still more surely by evapo- 

 rating the liquid at the ordinary temperature under the 

 receiver of an air-pump only, and it is a fact deserving 

 attention, that the thickest syrup that can be thus obtained, 

 does not crystalise even after the lapse of many days. 

 The addition of a small quantity of alcohol appears neces- 

 sary to determine the crystalization, which then becomes 

 complete in a few hours. This effect is probably due to 

 the coagulation of the vegetable albumen which exists in 

 very minute quantity, as we shall presently see. 



I have ascertained by the common processes, the other 

 substances that exist along with sugar in the cane juice. 

 By evaporating a given weight of vesou, and incinerating 

 the residue, we get 1.3 per cent, of white ashes. 



These ashes consist of sulphate of potass, lime, alkaline, 

 chlorate, and other salts, found in the sap of almost all ve- 

 getables. 



The sub-acetate of lead which precipitates all organised 

 substances except sugar, and which produces especially so 

 considerable a precipitate from beetroot, causes only a slight 

 quantity of greenish deposit from cane juice. Admitting 

 vegetable albumen to be the organic substance united to 



