180 
IOWA ACADEMY OF SCIENCES. 
by what is termed the ‘^spirituous fermentation” of sac- 
charine juices. These juices occur in many plants and 
fruits and belong, in chemical classification, to the carbohy- 
drates, which may be arranged into the following classes: 
1. Glucoses, or Monoses, having the formula Ce H12O0 . 
Grape sugar and fruit sugar are the more important repre- 
sentatives of this class. 
2. Saccharobioses, with the formula C12H22O11, whose 
chief sugars are malt sugar, cane sugar, and milk sugar. 
8. Polysaccharides, whose formula is (OeHioOsjx. 
Starch and dextrine constitute the more important mem- 
bers of this class. 
The simple sugars of the formula C6H12O6 are capable of 
direct alcoholic fermentation. This is especially true of 
grape sugars and of fruit sugars, as well as of most sugars 
among the saccharobioses. Commercially, it is of the 
greatest importance that the saccharobioses and polysac- 
charides, which are not directly fermentable, may be con- 
verted by water absorption into directly fermentable 
sugars and these then fermented. 
Absolutely pure ethyl alcohol is a mobile, colorless 
liquid with an agreeable odor. It boils at 78.3° and has a 
specific gravity of 0.80625 at 0° . At -90°, it assumes the 
appearance of a thick liquid, and at -130°, it solidifies to 
a white mass. It burns with a non-luminous flame and 
absorbs water energetically from the air. 
The passing from an inorganic to an organic compound, 
without the intervention of Nature, was considered an im- 
possibility by chemists, until 1828, when Wohler synthe- 
sized urea from isocyanate of ammonium. Since that time 
many organic compounds have been made in the labora- 
tory, some of which have not as yet been discovered in 
nature. A very familiar illustration of this transition is 
found in the production of acetylene from calcium carbide, 
the equation of the reaction being: 
CaCg + H2O = C3H2 + CaO (1), or 
CaCg + 2H2O = C3H2 + Ca(OH)2 (2). 
