74 HOW CEOPS GEOW. ^ 



lasses. Iimlin is converted into this sugar by long boil- 

 ing with dilute acids, or with 'water alone. When pure, 

 it is a colorless, amorphous* mass. It is* incapable of crys- 

 tallizing or granulating, and usually exists dissolved in a 

 small proportion of water as a syrup. .Its sweetness is 

 equal to that of saccharose. 

 Levulose contains in 100 parts : 



Carbon 40.00 



Hydrogen 6.67 



Oxygen 53.33 



100.00 



* 



Glucose or Grape Sugar, C ia H 24 O 12 , naturally occurs 

 associated with levulose in the juices of plants and in 

 honey. Granules of glucose separate from the juice of the^ 

 grape in drying, as may be seen in olcl " candied " raisins. 

 Honey often granulates, or candies, on long keeping, from 

 the crystallization of a part of its glucose. 



Glucose is formed from dextrin by the action of hot 

 dilute acids, in the same way that levulose is produced 

 from inulin. In the pure state it exists as minute, color- 

 less crystals, and is, weight for weight, but half as sweet 

 as the foregoing sugars. In composition it is identical 

 with levulose. 



It combines chemically with water in two proportions. Mono-hy- 

 drated glucose, (C 12 H 24 Oj 2 H 2 O,) or Anthon's hard crystallized grape- 

 sugar, which is prepared in Germany by a secret process, is dry to the 

 feel. Bi-hydrated glucose, (Ci 2 H 24 O 12 2H 2 O,) occurs in commerce in an 

 impure state as a soft, sticky, crystalline mass, which becomes doughy 

 at a slight!}' elevated temperature. Both these hydrates lose their crystal- 

 water at 212. 



Dissolved in water, glucose yields a syrup, which is 



thin, and destitute of the ropiness of cane-sugar syrup. 



It does not crystallize, (granulate,) so readily as cane-sugar. 



EXP. 30. Mix 100 c. c. of water with 30 drops of strong sulphuric 



acid, and heat to vigorous boiling in a glass flask. Stir 10 grams of 



* Literally without shape, i. e., not crystallized. 



