lis 
much decaying vegetable matter, and they acquire a mealy 
consistence ; but it decreases when the soil is manured with 
strong animal manure, although the number of cells increases, 
and they become soapy. Beet roots taken from a barren, 
sandy soil contain a maximum of sugar, and no ammoniacal 
salts. And the Teltona turnip loses its mealy property in a 
manured land, because then cells are formed in its substance. 
The exudations of mannite or gum in strong healthy plants is 
owing to a want of nitrogenous manures. 
Now all plants cultivated by the agriculturist contain more 
or less of nitrogen, and the value of them as food is propor- 
tionate to the quantity of this substance which they may con- 
tain, i. e., the cerealia contain the greatest quantity, and are 
accordingly the most valuable of our cultivated crops ; but 
this is not all, for the greater the quantity of azotized substances 
which may he used as manures^ the greater the quantity of 
produce ; and the chief art of agriculture depends not only 
upon the collection and preservation of those manures which 
contain ammonia in the greatest quantity, but also on the just 
application of it to those cultivated plants lohich require it. 
In order therefore to afford a clear view of those manures 
which contain the greatest quantity of ammonia, and also of 
those plants which require or contain the most nitrogen in 
their component parts, I have added a list of manures, each 
standing in the order in which they are most valuable. 
The following is a list of manures, &c. : — 
[See Table at the end.] 
1. The urine of the horse contains 10 per cent, ammoniacal 
salts. 
2. The urine of the cow contains 7 per cent, ammoniacal salts. 
3. Of that of the sheep no analysis has been obtained. 
Then follow the the solid excrements which are greatly inferior 
to the urines. 
Concerning solid excrements — 
The dung of the horse contains only 1 per cent, of nitrogen. 
That of the cow 1 in 200,000 parts. 
