C. H. Bailey 4'il 



gravity of these samples were then deterniiued and the results of these 

 tests, the flour yields, and the percentages of total nitrogen are shown 

 in Table IV. The data are grouped according to type of wheat, i.e., 

 winter or spring, and into two sub-groups in each case according to 

 relative hardness. While there is some overlapping in the case of the 

 flour yields from the vitreous and mealy samples, the general tendency 

 was decidedly in the direction of larger flour yields from the vitreous 

 grain. The relation between density or specific gravity and percentage 

 of nitrogen is also marked, the samples having a lower specific gravity 

 almost invariably having a low nitrogen content as well, when the 

 comparison is restricted to kernels of about the same volume or 

 plumpness. 



For comparison with the hard wheats of the northern Great Plains 

 area, a number of samples of soft red winter wheats grown in the eastern 

 half of the United States were secured through representatives of the 

 Office of Grain Standardization of the United States Department of 

 Agriculture. The results of the tests of these samples are given in 

 Table V. They are arranged in two groups, those having a nitrogen 

 content of less than 1-80 per cent, being included in the first group, 

 and those .of 1-80 per cent, or over in the second group. These soft 

 red wheats have a lower average specific gravity and nitrogen content 

 than the hard wheats, although the average kernel volume is greater. 

 The same relation between nitrogen content and specific gravity prevails 

 here as did in the case of the hard wheats studied, viz. the higher the 

 nitrogen content, the greater the specific gravity, as a general rule. 



Summary. 



Kernel volume, because of its relation to the ratio of endosperm to 

 non-endosperm structures, varies directly with the potential flour 

 yield when comparisons are restricted to the same type or variety of 

 wheat. 



Accurate determination of kernel density must include the complete 

 removal of all mechanically held air. 



Large kernels, other things being equal, have a higher specific 

 gravity than small kernels of the same variety, indicating the endosperm 

 to have a higher specific gravity than the bran and germ. 



Relative density of the endosperm is generally conceded to be 

 dependent upon the proportion and size of the air vacuoles. Soft, 

 Ught-coloured, yellow-berry kernels have a lower specific gravity than 



