36 QUARTERLY JOURNAL. 



known that to be fertile a soil must contain a certain proportioi 

 of vegetable matter. 



That soils become exhausted of the saline portions more rapidl: 

 than of the other, cannot be wondered at, when it is remember 

 that these substances are restored in much the least proportion 

 in ordinary cases. The solid excrements of animals which consti- 

 tute the mass of manure commonly applied, contain but little ol 

 them, whilst the liquid excrements which abound in them are suf 

 fered to run to waste. The thorough, rational farmer will alway; 

 restore what is taken away. 



We might carry this idea out to a greater extent, by turning t( 

 the animal and reasoning from analogy, which will hold good, W' 

 think, in this point. The same materials are necessary in th 

 animal economy as in the vegetable. Yet no one will pretend t 

 say that one class of substances is more useful to the general lif' 

 and growth of the animal than another. All must be supplied i 

 their due proportion. 



We conclude, then, that neither the inorganic nor the organ), 

 portions of manures determine their value — that lanraonia, suppose 

 to owe its efficacy to its nitrogen, an almost undiscoverable quar 

 tity in most plants, and by many called " the life and soul of m; 

 nure," is not the controlling force — but that each substance nece 

 sary to the plant has an equal effect in perfecting its structure ar 

 promoting its growth. 



The simple experiment that would set this matter at rest, wMj 

 suggest itself to any reflecting mind, and it is to be hoped th:|' 

 some one will make it. 



2. At what period should manures be applied 1 The questicj 

 which we have just briefly examined, we have attempted to answf 

 upon the general principle. But in replying to this we might vol 

 naturally be led into the consideration of special manures, becauiiB, 

 from the facts in the case it is unquestionable that at differe: 

 periods of growth, and also according to the kind of product tol; 

 obtained, plants must be supplied with different food. By refei 

 ring to the first volume of this Journal, page fifty-three, tables wi' 

 be found giving the different quantities of ash left by burning di| 

 ferent parts of the same plants. It will then be seen that whe| 

 straw leaves 3.51 lbs. in 100, whilst the grain leaves but 1 . 18 Ibj 

 Now these unequal quantities in the different parts show beyondl 



