546 



OLEAGINOUS PLANTS. 



No. 1. No. 2. 



Water .... 8.32 .. 16.31 



Oil 24.32 .. — 



Nitrogen .... 3.05 3.35 



Ash . . . . . 7.22 .. 4.95 



The ash contains — 



Siliceous matters . . , 1.96 .. — 



Phosphates .... 3.36 .. 2.27 



Excess of phosphoric acid . . 0.64 . , — 



In order to give a proper idea of the value of this substance as 

 a manure, I shall quote here, for comparison sake, the average 

 composition of rape cake, as deduced from the analyses contained 

 in the Transactions of the Highland Society of Scotland : — 

 Water ...... 10.68 



Oil ...... . 11.10 



Nitrogen . . . . . .4.63 



Ash ...... . 7.79 



The ash contains — - 



Siliceous matters . . , . .1.18 



Phosphates ...... 3.87 



Excess of phosphoric acid .... 0.39 



It will be at once seen that there is a close general resemblance 

 between these two substances, although there is no doubt that the 

 castor cake is inferior to rape cake ; still I believe that this inferi- 

 ority is fully counterbalanced by the difference in price, which is 

 Buch that, compared with rape cake, the castor cake is really a 

 cheap manure. There is only one of its constituents which it con- 

 tains in larger quantity, and that is the oil. No weight is, how- 

 ever, to be attached to the quantity of oil in a manure. In a 

 substance to be used as food, it is of very high importance ; but 

 BO far as we at present know, its value as manure is extremely 

 problematical. AYhale, seal, and other coarse ods have been used 

 as manures, and by some few observers benefits have been derived 

 from their application, but the general experience has not been 

 favorable to their use, nor should we chemically be induced to ex- 

 pect any beneficial efi'ect from them. We have every reason to 

 believe that the oils which are found in plants are produced there 

 as the results of certain processes which are proceeding within the 

 plant, and there is no evidence to show that any part of it is ever 

 absorbed in the state of oil by the roots when they are presented 

 to them. On the other hand, the oils are extremely inert sub- 

 stances, and undergo chemical changes very slowly ; so that there 

 is no likelihood of their being converted into carbonic acid, or any 

 other substance which may be useful to the plant ; and as they 

 contain no nitrogen, and consist only of carbon, hydrogen, and 

 oxygen, they can yield only those elements of which the plant can 

 easily obtain an unlimited supply. I can conceive cases in which 

 the oil might possibly produce some mechanical efi'ect on the soil, 

 but none in which it could act as a manure, in the proper sense of 

 the term. 



Kanaei oil. — Mr. Crawfurd, in his " History of the Indian 

 Archipelago," speaks most favorably of an oil obtained from the 



