PROCEEDINGS OF THE CHEMICAL DEPARTMENT. 187 



oily 628 lbs. were silica. It is clear, therefore, that as far as all 

 mineral matters, except silica, are concerned, the bean draws 

 more largely on the soil than wheat. At a later period of its 

 growth, when its leaves decay, a good deal of this mineral 

 matter returns to the land, but still in the straw and beans the 

 quantity of matters removed is much larger than that carried off 

 by wheat, and we see, therefore, how important it is to save and 

 restore to the soil the straw of this plant. 



I refrain at the present moment from drawing any compari- 

 son between the bean and the other crops analysed, as it appears 

 better not to take up the minute consideration of the various 

 questions which arise, until a larger number of plants has 

 been examined. 



III.— OX THE ADULTEEATION OF OIL-CAKE. 



There is probably no article of agricultural consumption 

 which is at present so frequently and grossly adulterated as oil 

 cake. The fraud, too, is one of comparatively recent introduc- 

 tion, for even ten or twelve years since it was rare, while now 

 it has attained really gigantic proportions, and is carried on with 

 such skill and ingenuity, that the most experienced purchaser is 

 liable to be deceived, even when he exercises all his prudence 

 and caution, for the mixtures which are offered to him are not 

 only the most perfect imitation of the genuine article, but it not 

 unfrequently happens that an adulterated cake will, to the eye, 

 appear superior even to those which, though genuine, are not of 

 the highest quality. 



This adulteration is a subject which must at all times attract 

 the attention of the feeder, but becomes doubly important at the 

 present time, when epidemic disease is rife, and when nutritive 

 food of the best quality is of especial importance, for it is by 

 maintaining stock in the highest state of health that they are 

 most likely to resist its attacks. I propose, therefore, in the 

 present paper, to direct attention to the composition and nature 

 ■ of adulterated cakes ; and it is the more necessary to do this, 

 because considerable misapprehension appears to exist as to the 

 mode in which its quality is to be estimated. The farmer most 

 commonly judges by the eye, and if the appearance of the cake 

 be good, and its taste sweet and free from bitterness, he is often, 

 indeed most generally, satisfied. If he is more cautious, he 

 demands the analysis of the cake he is about to buy, and ascer- 

 tains whether the amount of oil, albuminous compounds, &c, 

 come up to the standard to which he has been accustomed. 

 Both methods of judging are fallacious ; the first, no doubt, 

 more so than the second, for the adulterator, dealing with the 



