26 THE BOOK OF WHEAT 



The substances of which wheat flour is composed may be di- 

 vided into three classes : (1) Nitrogenous, which include main- 

 ly gluten, fibrin, albumen, casein, cerealin, and modifications of 

 some of these; (2) non-nitrogenous, embracing sugar and dex- 

 trin, but chiefly starch, fat and cellulose; and (3) the minerals, 

 for the largest part alkaline phosphates and silicates, espe- 

 cially phosphate and silicate of potash. 



WATER. Wheat ordinarily contains from 10 to 15 per cent 

 of moisture. Changes in the moisture content of the air cause 

 corresponding variations in wheat, and consequently in its 

 weight. Usually such fluctuations in weight do not exceed 6 

 per cent, but they may be as much as 25 per cent, and an in- 

 crease of 9 per cent in 24 hours has been observed. When 

 wheat is shipped, especially if it is transported long distances, 

 this may be a matter of great commercial importance. Wheat 

 transported from the dry atmosphere of the inland of Cali- 

 fornia to ordinary temperate regions will invariably gain from 

 5 to 15 per cent in weight. In a voyage from San Francisco 

 to Liverpool, the increase in weight due to the moisture ab- 

 sorbed en route may be sufficient to pay all expense of transpor- 

 tation. Every portion of the wheat grain is so susceptible to 

 influence from hydroscopic conditions that all of the products 

 of wheat exhibit similar oscillations in weight. Two days 

 equalized the moisture content in samples of flour varying from 

 less than 8 to over 13 per cent. 1 



ASH. Lawes and Gilbert observed the composition of the 

 ash of wheat grown on unmanured ground during 20 years. 

 The average results are given in the table below. 2 



Grain 



Ferric oxide 0.645 



Lime 3.175 



Magnesia 10.48 



Potash 33.345 



Soda 0.18 



Phosphoric anhydride (P 2 5 ) 50.065 



Sulphuric anhydride (SO 3 ) 1.42 



Chlorine 0.05 



Silica 0.655 



Total 100.015 100.485 



1 Hunt, Cereals in Amer. (1904), p. 38; Mich. Bui. 191, p. 159-164. 



2 Hunt, Cereals in Amer. (1904) p. 39. 



