502 INFLUENCE OF CLIMATE, VARIETY OF SEED, 



Weight Water 



per in Gluten. 



KiNP OF WHEAT, bushel. Flour. where grown. 



lbs. per ct. per ct. 

 Red English ... . 62^ 17-5 81 At Sunderland Bridge, near Durham. 



" " ,... 62^ 16-4 95 At Kiniblesworth, near Durham. 



" « .... 63 150 8-5 At Hougliall, near Durham. 



« " 62| 16-8 9 9 Near North Deighton, Yorkshire. 



White " .... 63 15 5 75 At Flaw svvorth, near Durham. 



" Scotch.. 61^ 16-3 9-4 At Gadgirth, near Ayr (Appendix, p. 39.) 



Red Stettin 63 14-6 8 6 



« Odessa.... 61 15-9 US 



In all these cases the quantity of gluten falls far short of that assigned to 

 English flour by Davy ; yet we may safely, I think, conclude from them 

 that English flour seldom contains more than 10 per cent, of dry gluten. 

 The flour from North Deighton, which gave 9-9 per cent, was grown 

 upon a thin limestone soil, and may perhaps owe its larger per-centage 

 to this circumstance. 



But these numbers do not indicate the exact quantity of nitrogen-hold- 

 ing food which these flours contained. For in the gluten there is al- 

 ways present avariablequantity of fatty matter which contains no nitrogen, 

 and which, if extracted, would lessen considerably the weight of the glu- 

 ten in some of the flours. On the other hand, however, the water em- 

 ployed in washing out the starch holds in solution some albumen and 

 casein, which, having the same composition, might be added to the glu- 

 ten, and would sensibly increase its weight. Thus in a sample of flour* 

 grown in Ayrshire I found — 



Gluten .... 9-3 per cent. 

 Albumen .... 0-45 per cent. 

 Casein .... 0*40 per cent. 



Making in all . . . 10-15 of substances which contain 

 nitrogen in nearly equal proportions. 



We probably, therefore, do not greatly err in general in estimating 

 the nutritive value of wheaten flour — in so far as it depends upon these 

 nitrogenous compounds — by the per centage of dry gluten which a care- 

 ful washing enables us to separate from it. Further researches, how- 

 ever, which are now in progress, will throw much additional light upon 

 this subject. 



§ 10. Influence of variety of seed, of mode of culture, of time of cutting, 

 and of special manures, on the composition of wheat. 

 1°. Variety of seed and mode of culture. — The influence of these two 

 circumstances upon the relative proportions of bran and gluten are sjiown 

 by the following results of the examination by Boussingaultf of several 

 varieties of wheat grown in the Botanic Garden at Paris — 



Husk or Bran Flour Water Gluten, &c. 



in the Grain, in the Grain, in the Flour, in the Flour. 



per cent. per cent per cent. per cent. 



Capewheat 19 81 7-0 20-6 



Russian wheat 18 82 6-4 24-8 



Dantzic wheat 24 76 73 25-8 



Red Foix wheat 185 815 9-3 26-1 



BaiTel wheat 22 78 8-8 277 



Winter wheat 38 62 141 33 



' No. 2. Appendix, p. 171. 



t Annalet de Chim. et de Phya. Izv., p. 311. 



