CANE-SUGAR. 199 



candy, well developed regular crystals. Soluble in one- 

 third part of water ; in alcohol the less soluble the 

 less water it contains. Fusible at 160. The solution 

 rotates the plane of polarization to the right, and does 

 not reduce an alkaline solution of copper. 



Sugar combines with bases. A saccharine solution 

 dissolves a large amount of calcium and barium hy- 

 droxides, and loses by this means its sweet taste. 

 Further, it dissolves lead oxide, forming a soluble sac- 

 charate, which has an alkaline reaction. All of these 

 compounds, however, are decomposed even by carbonic 

 acid. 



Decompositions. Heated to the fusing point, sugar 

 becomes amorphous without losing water, and becomes 

 crystalline again only after standing for a long time. 

 It suifers the same alteration when its solution is 

 boiled for a long time. Heated to 190-200, it is con- 

 verted into a brown, uncrystalline mass called caramel. 

 Distilled with a large excess of caustic lime, sugar is 

 decomposed into water, carbonic anhydride, acetone, 

 and metacetone C 6 H 10 0, a colorless, agreeably smelling 

 liquid, which boils at 84, floats on water, and, when 

 heated with potassium bichromate and sulphuric acid, 

 yields carbonic, acetic, and propionic acids. Melted 

 carefully with an excess of potassium hydroxide, sugar 

 forms potassium carbonate, oxalate, formate, acetate, 

 and propionate, hydrogen being evolved. 



Concentrated sulphuric acid converts cane-sugar into 

 a black mass, the action being accompanied by an ele- 

 vation of temperature and formation of formic acid. 

 Boiled with dilute sulphuric acid or with hydrochloric 

 acid, it breaks up into equal molecules of grape-sugar 

 and uncrystalline fruit-sugar, the elements of water 

 being taken up. It is not capable of fermentation as 

 such ; in contact with yeast, however, it is decomposed 

 in the same manner as by means of dilute acids, and 

 transformed into the two varieties of fermentable sugar. 

 When boiled for a long time with acids, it is converted 

 into brown bodies. 



Gently heated with nitric acid, it yields saccharic, 



