SUGAR. 115 



It in admitted at tho p.esent time that fermentable sugars must be 

 divided into two principal species, in harmony with characters which 

 are most easily appreciated. One of these presents itself in the 

 shape of hard, transparent crystals, and is met with in sufficient 

 quantity to be profitably er.tracted from the juice of the cane and the 

 beet, the sap of the maple and of certain palms ; the other is obtained 

 with some difficulty in the solid state, being most frequently and 

 readily procured in the iorm of sirup ; the taste of this is less sweet, 

 less decided ; it exists in the grape and the greater number of 

 fruits. The chemical characters of these two kinds of sugar, which 

 are designated, cane-sugar and grape-sugar, are somewhat ditFerent ; 

 and the elegant researches of M. Biot have shown, that from some 

 of their physical properties, particularly the action of their solutions 

 upon polarized light, they cannot be regarded as constituting one and 

 the same species. In the vegetable kingdom, these two kinds of 

 sugar are frequently met with mixed ; and there are certain chemi- 

 cal means which enable us readily to transform cane-sugar into 

 grape-sugar. The inverse transformation has not yet been accom- 

 plished ; but there is nothing which leads us to conclude that it is 

 impossible; and the time, perhaps, is not very remote when the 

 sugar which is manufactured from potato-starch may be changed 

 into crystallized sugar, similar to that which is obtained from the 

 cane. 



Crystallized svgar. Cane-sugar is readily obtained in large 

 transparent crystals, which are known under the name of sugar- 

 candy. Sugar is fusible : under the action of a regulated tempera- 

 ture, it acquires a dark-red color, and passes into the state of cara- 

 mel; a higher temperature effects its decomposition. It is much 

 less soluble in alcohol than in water ; highly concentrated alcohol, 

 indeed, only dissolves an extremely small quantity of sugar. 



M. Peligot's analysis of cane-sugar shows it to be composed of — 



Carbon 42-1 



Hydrogen 6.4 



Oxygen 51.5 



100.0* 

 Such is the composition of sugar dried at the temperature of boil- 

 ing water ; but the substance, like the majority of organic matters, 

 still contains a certain proportion of constitutional water, which it 

 abandons when it combines with certain bases. Thus sugar com- 

 bines with oxide of lead, and forms a true saccharate, in which the 

 sugar, deprived of its water of constitution, plays the part of an acid ; 

 this combination, which presents itself to us under the form of white 

 mammillated crystals, analyzed by M. Peligot, would indicate tho 

 following as the composition of anhydrous sugar — 



Carbon 47. 1 



Hydrogen 5.9 , 



Oxygen 47.0 



100.0 



• Annales de Chimie, vol. Ixviii. p. 134, 2e s6rle. 



