42 BULLETIN 878, TJ. S. DEPARTMENT OF AGEICrLTUEE. 
Station. Since 1918, the laboratory has been located at Washington, 
D. C, and the experiments have been conducted in cooperation with 
the division of milling investigations of the Bureau of Markets. The 
nitrogen determinations have been made since 1918 by the Bureau of 
Chemistry of the United States Department of Agriculture and by 
the research laboratory of the Bureau of Markets. Complete data 
regarding the flour and bread producing qualities of each lot of wheat 
have been obtained, but data on only three important factors are 
presented here. These are percentage of crude protein in the wheat, 
percentage of straight flour in the wheat, and loaf volume (in cubic 
centimeters) of bread baked from 340 grams of flour. The average 
results shown here are from varieties grown during three or more 
station years. The average data obtained from two samples is an 
indication of milling and bread-making value, but three or more 
samples should be milled and baked before definite conclusions are 
drawn. 
CRUDE PROTEIN IN WHEAT. 
Each sample of wheat is analyzed for nitrogen. The percentage of 
crude protein is the percentage of nitrogen multiplied by the factor 
5.7. The result is then computed to a standard basis of 13.5 per cent 
moisture in the wheat, as all samples vary somewhat in moisture 
content. The protein content of wheat is an indication of the 
strength of the flour and of the gluten content. The best wheats 
contain considerable protein, but as there are other important char- 
acters this should not be used alone in making comparisons. The 
average percentages of protein in 20 varieties of spring wheat, com- 
pared with Marquis wheat during the same station vears, are shown 
in Table XIX. 
Marquis wheat has an average protein content of 15.3 per cent. 
Most of the common spring wheats have about the same protein 
content as Marquis. Ghirka Spring and Galgalos are softer wheats 
and have distinctly less protein. Huron also has a low percentage 
of protein. The Prelude and Pioneer varieties are early-maturing 
hard red wheats having a high protein content. The Manchuria 
is a very soft wheat and is poor in all milling and baking factors ex- 
cept that it has a high average protein content. 
The durum wheats in these experiments have about the same 
percentage of protein as Marquis. Monad is the only variety showing 
a distinctly greater protein content. 
