SUGAR-CANE. 121 



to prevent it. The alkaline iarth, as I have had occasion tc say, 

 • by no means indispensable ; its utility under ordinary circunistan- 

 ces is probably confined to assisting the defecation by forming an in- 

 soluble precipitate with some of the organic substances which are 

 always met with in small quantities in cane juice ; perhaps also to 

 making an earthy soap with the fatty matters which adhere to the 

 cane and are expressed in the crushing. When lime is added, to 

 correct acidity, it forms an acetate or a lactate, salts which are pe- 

 culiarly soluble, uncrystallizable, and which necessarily retain a 

 quantity of sugar in the sirupy state. 3. The presence of certain 

 mineral salts in the cane. Common salt, for instance, in combining 

 with sugar forms a deliquescent compound, in which one part of salt 

 is united with six parts of sugar ; such a compound as this of course 

 renders a large quantity of sirup indisposed to crystallize. It is 

 therefore impossible to be too cautious, according to M. Peligot, in 

 the choice of manure for a cane-field ; that which contains any com- 

 mon salt must needs be injurious in one way, however advantageous 

 it may be in another. The entire absence of this salt in the soil of 

 plantations which are very remote from the sea shore is perhaps one 

 of the causes which increases the quantity of sugar obtained from 

 the crop, and makes it more easily manufactured in such districts. 



M. Codazzi reckons the quantity of white sugar produced by a 

 hectare of land, (2.473 acres,) planted with the Otaheite cane in the 

 province of Caraccas, at 1875 kilogrammes, or 36 cwt. 3 qrs. 9 lbs. 

 avoir. ; which is at the rate of 15 cwt. 1 or. 10 lbs. per acre. 

 Taking 7| per cent, as the average quantity jf sugar obtained, the 

 weight of cane brought to the mill must obviously have amounted to 

 19134 kilog. or 18 tons, 15 cwt. 3 qrs. 10 lbs. ; or 7 tons, 11 cwt. 

 3 qrs. 25 lbs. per acre. Assuming the average composition of the 

 plant to be — 



Wood (dry) 11.0 



Sugar (minimum) 15.5 



Water .73.5 



100.0 



One acre of land will consequently yield a crop of — 



Tons. Cwt. Qrs. Lb* 



Wood (dry) 16 2 24 



Sugar 1 3 2 6 



Water -5 i^ ^ I? 



7 11 3 25 



The trash of the sugar-cane undergoes rapid fermentation : it soon 

 exhales a distinct smell of vinegar, and almost the whole of the 

 sugar which is left in it is destroyed. 



BEET-ROOT SUGAR. 



The presence of sugar in the beet was observed by Margraff; and 

 Achard of Berlin by and by attempted the extraction of this sugar 

 on the large scale ; but it was only during the period of the conti- 

 nental system that the manufacture of sugar from the beet acquired 



11 



