14 



is found to vary materially from year to 5^ear, depending among other 

 thino-.s upon the amount of rainfall and the climatic conditions under 

 which the wheat has matured. The wheat crop produced in the north- 

 western United States in 1900 was unusuall}* rich in protein. The 

 rainfall and climatic conditions seemed to be particularly favorable for 

 producing wheat and other grains with a high nitrogen content. While 

 the wheat employed in this investigation contained somewhat more 

 protein than is found in average wheat, in the author's opinion the 

 percentage is no greater than in average wheat grown in the north- 

 western United States in 1900. All of the flour samples from this 

 wheat were relativeh' richer in protein than those in similar investi- 

 gations with hard wheat in 1898-99, owing to the high nitrogen con- 

 tent of the wheat. The difi'erences in the protein content of the several 

 grades of flour ground from the wheat were comparatively small. 



There was a higher percentage of fat in the middlings than in the 

 bran, owing to the presence of the germ in the former. Red-dog flour 

 is the richest, as regards both fat and protein, of the products ground 

 from the wheat. In the case of the patent and clear grades of flour, 

 the heat .of combustion as determined was found to agree closely with 

 the heat of combustion obtained by calculation, using the usual factors, 

 namelv, 9.3 calories per gram" for fat, 5.9 for protein, and 1.2 for 

 carbohydrates. As pointed out in a previous report,* the percentage 

 of ash in the various products of wheat was lowest in the first 

 patent flour and highest in the red-dog flour. Each grade of flour, 

 beginning with the first patent, was found to contain proportionall}' 

 more ash than the preceding grade. In fact, as noted previously, the 

 grade of flour can be determined from the amount of ash present. In 

 the analyses reported above the ash content is greater than in the 

 samples employed in the earlier work with hard wheat in this labora- 

 tory. There appears to ])e a close relationship l^etween the amounts 

 of ash and protein present in flour and other milled products of wheat, 

 an}' material increase in protein being accompanied b}^ a correspond- 

 ing increase in mineral matter. This has often been attributed to the 

 phosphorus associated with the proteids. Late work of Osborne*' 

 indicates that the total amount of phosphorus in wheat proteids is 

 too small to account for the increase in mineral matter just alluded to. 



The distribution of the nitrogen and ash constituents of the wheat 

 berrv has been frequently studied, and it is interesting to note some 

 comparatively recent American work on the subject, particularly as 

 the investigations were made with wheats grown in the United States, 

 which are therefore directly comparable with the wheats used in the 

 investigation reported in this bulletin. 



Mrs. Ellen H. Richards and Miss Lottie A. Bragg '^ studied the distri- 



«U. S. Dept. Agr., Office of Experiment Stations Bui. 101, p. 12. ^ lb., p. 9. 



c Connecticut State Station Rpt. 1900, p. 464. c^Tech. Quart., 3 (1890) , p. 246. 



