eiRUCTURE OF "WHEAT 37 



five per cent or the seed coats must be largely composed ot 

 something else than crude fiber. 



65. Physical Properties. — Richardson found as the result ot 

 377 determinations that there were about 12,000 grains in a 

 pound of wheat; in some samples there were less than 8,000, 

 while in others 24,000 grains to the pound. Obviously, so far 

 as mdividual grains are concerned, one bushel of seed in the 

 one case w^ould be equivalent to three bushels in the other. 

 Pammel and Stewart report variations in the specific gravity of 

 American grown varieties from 1.146 to 1.5 18. 



The hardness of the grain varies greatly. Generally the 

 harder grains contain the higher per cent of total nitrogen and 

 of gluten. The relation between hardness and specific gravity 

 has not as yet been clearly demonstrated, although Lyon has 

 shown that high specific g^ravity is associated with low nitrogen 

 content.^ 



Komicke and Werner ^ state that the specific gravities of the 

 various chemical constituents of the wheat grain are as follows : 

 Starch, 1.53; sugar, 1.60; cellulose, 1.53; fats, 0.91-0.96; gluten, 

 1.30; ash, 2.50; water, i.oo; air, .001293. 



The standard (and generally legal) weight per bushel (2150.42 

 cu. in.) of wheat is sixty pounds. The weight of a measured 

 bushel not infrequently varies from fifty-five to sixty-five pounds 

 per bushel, and greater extremes have been noted. 



The color of the grain varies from a very light yellow through 

 varying grades of amber to dark red. Hardness of grain and 

 high nitrogen content are usually associated with the deeper red 

 color. 



The grain may vary in length, in transverse or cross section 

 outline, or in depth of crease or furrow. All of these characters 

 may be used in describing varieties of wheat. (201) 



1 A Method for Improving the Quality of ^\^leat for Breadmaking. Tnesis for 

 degree Ph.D., Cornell, 1904. 



2 Handbuch des Getreidebaues Bd. 2s. 120. Berlin. 188^ 



