14 VOELCKER on the Chemistry of Food. 



rarely quite free from mustard, therefore may be given with 

 greater advantage to sheep than to cattle. 



The fact that some samples of rape-cake are full of mustard 

 and others comparatively free from it, perhaps accounts also for 

 the differences of opinion which farmers who have tried rape- 

 cake entertain respecting its feeding value. Rape-cake, free 

 from foreign seeds and well kept, may indeed be a valuable and 

 economic article of food; but there is often rape-cake sold to 

 farmers which contains so much mustard that it is difficult to 

 decide whether the cake is rape or a mustard cake. Such cake 

 should never be used for feeding-purposes, for it is certain to 

 injure the condition of the animals to which it is given. 



Linseed-cake is manufactured in England ; in America, France, 

 Holland, Germany, Russia, Belgium, Italy, and other continental 

 countries, and imported into England under names denoting the 

 country in which they have been manufactured. 



English cake is generally preferred to all other varieties, and 

 fetches usually a higher price in the market. However, much 

 depends upon the fancy of the purchaser : thus, whilst in most 

 localities English cake is preferred to American, I am told the 

 latter fetches a higher price in Exeter market than English. 



This circumstance led me to ascertain whether there was any 

 real difference in the composition of two samples of American 

 and English linseed, which were bought last season at Exeter, 

 with a greater expenditure of 17. per ton for the American cake. 

 Without mentioning the details of my examination, I will briefly 

 state that both cakes were of excellent qualities, and that the 

 differences in the composition were so trifling, that both might 

 be regarded, for practical purposes, to be identical. Neither in 

 their chemical composition, nor in their physical properties, could 

 any marked difference be detected which might account for the 

 higher price paid for the American cake in Exeter market. 



English cake, it is true, generally, though by no means always, 

 contains more oil than American or other foreign linseed-cakes, 

 but the differences in the relative proportions of oil in various 

 cakes are too inconsiderable to account for the higher estimation 

 in which English or American cakes are held. The superior 

 value of home-made and also of most American cakes, I believe 

 depends not so much on their chemical composition, as upon the 

 condition in which the cake is found in the market. Good home- 

 made cake, and most American cakes, are always dry and free 

 from mouldiness and rancid smell ; they have an agreeable 

 flavour and mild sweet taste, and for these reasons are more 

 highly appreciated than other foreign cakes, which generally 

 possess a more or less rancid smell and taste, and appear often 



