94 FIRESIDE SCIENCE. 



the varieties, and it is distinguished for the readi- 

 ness with which it crystallizes. The crystals are 

 four-sided prisms, with rhomboidal bases, and are 

 remarkably uniform in appearance. This is an ar- 

 ticle of luxury, rendered by habit almost a neces- 

 sary of life to every class of the community, and it 

 is consumed in vast quantities. Levulose or fruit 

 sugar cannot be crystallized ; it is a colorless syrup, 

 nearly as sweet as cane sugar, and more soluble in 

 water and alcohol than glucose. It is also more 

 easily altered by heat or by acids ; while, on the 

 other hand, it is less readily acted upon by alka- 

 lies or ferments. Glucose is now manufactured in 

 immense quantities in France, and to some extent 

 in this country. It is recognized ifl commerce 

 as a beautifully clear, heavy syrup, of a mod- 

 erate sweetness, somewhat resembling glycerine, 

 and is sold at a low price. It is used by confec- 

 tioners, brewers, and distillers in their various man- 

 ufactures and operations, but scarcely at all for 

 domestic purposes. It is also undoubtedly used to 

 adulterate the cheaper kinds of refined sugars, al- 

 though the writer has never met with an instance 

 of this kind of sophistication. It is made from 

 potato starch, by the action of oil of vitriol or sul- 

 phuric acid. Thick, gelatinous starch is placed in a 

 large clay or porcelain-lined vessel ; dilute acid is 

 added, and the mixture boiled for several hours. 



