C. H. Bailey 435 



yields obtained with this small equipment are not identical with those 

 obtained by large merchant mills working on the same materials, they 

 are comparative with each other if the experimental mill is properly 

 handled. 



The other two physical characteristics which bear the most definite 

 relation to milhng value are the density of the kernel, more particularly 

 that of the endosperm, and the moisture content. The moisture 

 content is considered as a physical rather than a chemical characteristic 

 since it can be altered by purely physical means. An increase in 

 moisture content above the normal results in increased losses through 

 evaporation, as has been shown by the writer^. In addition, damp 

 wheat presents certain mechanical difficulties in miUing, owing to its 

 soft character, which render more difficult the separation of the bran 

 and endosperm. For these reasons, and because of the increased 

 Uability of spoilage through fermentation and heating, damp wheat is 

 of less value to the miller than dry wheat. 



The density of the endosperm of the wheat kernel is known to vary 

 widely. These variations are commonly distinguished as "mealiness" 

 in the case of the less dense, and "flintiness," or a "vitreous," "horny" 

 or "corneous" condition in the case of the more dense. The light- 

 coloured condition of the endosperm frequently met with in the hard 

 red wheats is usually referred to as "yellow-berry"; when the entire 

 kernel is not affected it is sometimes called " piebald." These variations 

 in endosperm density have been the subject of numerous investigations. 

 Nowacki- states that the difference in appearance of mealy and horny 

 wheat kernels is due to the presence of a larger volume of air-spaces in 

 the former. Hacked (p. 26) says, "If the albuminoids so fill up the 

 intervals between the starch grains that the latter seem to be imbedded 

 in cement, the albumin appears translucent and the fruit is called 

 corneous: but if the union is less intimate, there remain numerous 

 small air-cavities and the albumin is opaque and the fruit is mealy. 

 Both conditions may occur in the same species or variety (wheat) and 

 they seem to be occasioned by differences in climate and soil. Corneous 

 fruits are usually richer in albuminoids than mealy ones of the same 

 species." Pagnoul* and Wollny^ found that the specific gravity of 



' Bailey. Canadian Miller and Cerealist, vol. VI. pp. 74-75, 1914 

 - Nowacki. Untersuchungen ilher das Reifen des Getreides, Halle, 1870. 

 3 Hackel. The True Grasses. Translation by Lamson-Soribner and Southworth. 

 New Yoi'k, 1890. 



■> Pagnoul. Ann. Agron. vol. xiv. pp. 262-272, 1888. 



^ WoUny. Forsch. a. d. Gehiete Agrikulturphysik, vol. ix. pp. 207-216, 1886. 



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