Probably the most striking difference in the average mineral composition of the grain of wheat is the very much lower proportion of phosphoric acid, and of magnesia also, in the dry substance of the best matured grain; and it is now known that these characteristics point to a less proportion of bran to flour, or, in other words, of a greater accumulation of starch in the process of ripening, and consequently of a whiter and better quality of bakers' flour. The study of the chemical composition of wheat and its products in the mill, therefore, and of the amount of fertilizing matters (nitrogen, phosphoric acid and potash) removed from the soil by the crop, becomes of direct interest not only to the producer from whose soil these ingredients are removed, but to the consumer of the byproducts as well, who desires to know what proportion of these elements of fertility he is returning to his own soil in the different products he may use as animal food. It is desirable also to determine what is the average composition of wheats and the flour made from them, in order to see in what direction efforts should be turned, by the selection of seed wheats, to improve the present varieties for the production of the best quality of flour.

This can only be done after we determine what variation there is for different years due to climatic influences and variations of soil, for it has been shown in our former papers that environment very largely influences the quality of wheat grain, and also of the flour. When these have been determined, than we may hope to be able to determine which factors under our control enter in to permanently improve the better flour-producing quality of wheats.

A mixture, in equal proportions, was made of Clawson, Mediterranean, and early amber wheats, and submitted to the mill, using the Hungarian roller process. From this mixture for each one bushel of the grain of 60 lb. weight was furnished the following proportion of products:

These data furnish us a means of estimating the amount of the different ingredients removed in the various products in one bushel of wheat with the foregoing component parts.

Flour

The analysis of the flour shows us that the 44 lb. obtained from the one bushel of grain would contain the following ingredients:

Wheat Middlings

The middlings form the inner coating of the wheat grain, next the floury or starchy portion, and contain particles of the germ and a larger percentage of carbohydrates than either shipstuff or bran, and a less proportion of fiber, while the percentage of albuminoids usually stands between that of shipstuff and bran. The following data are obtained from the 4 lb. procured from a bushel of wheat:

Shipstuff

That part separated and known as shipstuff is a very thin layer next outside of the middlings, and contains the germ not found in the middlings or left as a part of the flour. The quantity produced, 2 lb. from a bushel of wheat, is very small and rarely kept separate from the bran. The following shows the analysis:

Bran

Bran, the outer coating of the wheat, contains twice or three times as much fiber as does either of the other products from wheat, and proportionately less of each of the other ingredients except ash, which is greater, perhaps partly due to foreign matter adhering to the kernel. The following analysis shows the amount of constituents removed by the bran (10 lb.) from one bushel of wheat:

From the foregoing milling products obtained from one bushel of wheat of 60 lb. in weight, the ash on analysis gave the following constituents, which shows the amount that was abstracted from the soil by its growth:

CONSTITUENTS FROM ONE BUSHEL OF WHEAT.

Or we may express the results in another form, the amount contained in one ton of straw, and the products of 30 bushels of wheat, which may be reckoned as an average crop, expressing the amounts in pounds as follows:

AMOUNTS OF SELECTED CONSTITUENTS IN
THIRTY BUSHELS OF WHEAT AND ITS PROPORTION OF STRAW.

From numerous investigations it has been found that in regard to the nitrogen and the ash constituents, there is striking evidence of the much greater influence of season than of manuring on the composition of a ripened wheat plant, and especially of its final product - the seed. Further, under equal circumstances the mineral composition of the wheat grain, excepting in cases of very abnormal exhaustion, is very little affected by different conditions as to manuring, provided only that the grain is well and normally ripened. Again, it is found that the composition may vary very greatly with variations of season, that is, with variations in the conditions of seed formation and maturation, upon which the organic composition of the grain depends. In other words, differences in the mineral composition of the ripened grain are associated with differences in its organic composition, and hence the great value of proper selection both for seed and for milling purposes.