THE VOLATILE PAET OF PLANTS. 73 



granulated sugar, but in the form of rock candy may be 

 found an inch or more iu length. The crystallized sugar 

 obtained largely from the sugar-beet, in Europe, and that 

 furnished in the United States by the sugar-maple and 

 sorghum, when pure, are identical Ayith cane-sugar. 



Saccharose also exists in the vernal juices of the walnut, 

 birch, and other trees. It occurs in the stems of unripe 

 maize, in the nectar of flowers, in fresh honey, in parsnips, 

 turnips, carrots, parsley, sweet i^otatoes, in the stems and 

 roots of grasses, and in a multitude of fruits. 



Exp. 39. — Heat cautiously a spoonful of white sugar until it melts, (at 

 356° F.,) to a clear yellow liquid. On rapid cooliag, it gives a transpar- 

 ent mass, known as barley sugar, wliioU is employed in confectionery. 

 At a lii;;lier heat, it turns brown, frotlis, emits pun<;ent vapors, and be- 

 comes burnt sugar, or caramel, which is used for coloring soups, ale, etc. 



The qanuUty per cent ol saccharose in the juice of various plants is 

 given in the annexed table. It is, of course, variable, depending upon 

 the variety of plant in case of cane, beet, and sorghum, as well as upon 

 the stage of growth. 



SACCHAROSE IN TLAHTS. 



per cent. 



Sugar cane, average 18 Peligot 



Sugar beet, " 10 " 



Sorglium 9K Goessmann 



Maize, just flowered, S% Ludersdorff 



Sugar maple, sap,average 2}4 Liebig 



Ked maple, " " 2K " 



When a solution of this sugar is heated with dilute 

 acids, or when acted on by yeast, it is converted into a mix- 

 ture of equal parts of levulose, (fruit sugar,) and glucose, 

 (grape sugar.) 



The composition of saccharose is the same as that of 

 Arabic acid, and it contains in 100 parts : 

 Carbon 42.11 

 Hydrogen 6.43 

 Oxygen 51.46 



. 100.00 

 LeTuIose, or Fruit Sugar, (Fructose,) C„ H,, 0„, exists 

 mixed with other sugars in sweet fruits, honey, and mo- 



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