144 



On the Nitrate of Soda. 



ammonia, as actually giving 35" 1 per cent. " Such great difference," he 

 adds, " must be owing to some cause, and this we find in the different 

 methods of cultivation. An increase of animal manure gives rise not 

 only to an increase in the immber of seeds, but also to a most remark- 

 able difference in the gluten they contain." Sir H. Davy also says that 

 it abounds in wheat of warm climates, and that the wheat of the south 

 of Europe, in consequence of the larger quantities it contains, was pecu- 

 liarly fitted for making preparations of flour in which a glutinous quality 

 is considered as an excellence. 



The coincidence would be curious if the excellence of Neapolitan 

 macaroni made from wheat growing on a volcanic soil were to be traced 

 to nitrates found in the soil, though, as fermentation and decomposition 

 go on so much more rapidly in warmer climates, the nitrogen of the 

 ammonia evolved is probably sufficient to account for the glutinous cha- 

 racter of the wheat in such situations. Sir H. Davy says also that the 

 gluten in wheat, being in larger quantity than in other grain, seems to 

 form a combination with the starch and water which renders wheaten 

 bread more digestible than other species of bread. 



Bread in its formation takes up and consolidates one fourth of the 

 water used. A sack of Italian, Sicilian, or Russian (Odessa*) flour, 

 when tough in kneading, or, according to the baker, "/w// of proof or 

 gluten, takes up in consequence from five to six gallons more water 

 than a similar quantity of British flour, and makes in consequence from 

 four to six more quartern loaves. When the wheat in England is not 

 well harvested it is frequently necessary, in order to make a loaf which 

 will " standt up in the oven" and sell, to mix with it flours of the above 

 description. The experienced dealer who valued my sample of nitrated 

 wheat at once recognised its resemblance to Russian, and its bran, when 

 subsequently shown him, he said to be from foreign grain of the south. 



Starch is perfectly white, while albumen, the same substance as white 

 of egg, is of a greyish colour, and gluten by exposure to air becomes 

 brown. The flours called fines" and " extra-fines" are made from 

 Dantzic wheats when to be had. I am not aware of the exact propor- 

 tions of their ingredients, but from their whiter colour, and their taking 

 up in the formation of bread less water than wheats from the south, 

 they must contain more starch and less gluten and albumen. Our 

 British wheats used also for fines and extras, in which the former is 

 known to abound, are also whiter ; and as articles of luxury, it is true 

 that the whiter wheats bring a higher price. But flours from the south, 

 from containing more gluten, are browner, and seeming to be less well 

 dressed than they are, and to contain more bran than they do, sell at a 

 lower price ; still they go farther and make a more wholesome and 

 nutritious bread. The intelligent labourer, who bakes his own bread 

 from " seconds," knows this well ; it keeps him better up to his work 

 than whiter flours. 



In selecting their purchases, it is well known that some corn-dealers. 



* I have lately had some of this Odessa flour analysed. It gave 31 per cent, of 

 gluten. 



f It is the gluten in wheat-flour which causes the " rising of the dough ;'" the carbonic 

 acid gas disengaged by fermentation and detained by the viscid gluten distends and 

 converts the heavy tenacious paste into a light spongy loaf. 



