A PRIZE ESSAY. 
46 
mals, bugs, grasshoppers, &c., we can understand why 
their droppings are peculiarly rich in ammonia and 
salts. The strongest of all manures is found in the 
droppings of the poultry yard. 
But since these form but a small portion of the 
farmer’s stock, and are never regarded as a principal 
source of manure, their further consideration may be 
omitted. It may perhaps be here added, that as from 
their nature bird droppings run quickly into fermenta¬ 
tion, with warmth and moisture, so they act quickly, 
and are quickly done. They are more allied to sheep 
dung than to other manures. Their mould not being 
great, droppings of poultry require to be mixed with 
decayed vegetable matter, or loam. To this class be¬ 
longs the manure brought from the Pacific Ocean, un¬ 
der the name of guano , a Spanish word for excrement. 
New-England farmers can find cheaper sources of 
salts, to which the main value of guano is owing, and 
therefore, reader, we shall detain you no longer on 
this point. 
SECTION X. 
MINERAL SALTS, OR MANURES. 
Having- thus considered the salts derived »om the 
animal, let us now proceed to those derived li m the 
mineral kingdom. Among these, we shall find some 
whose action is similar to that of the animal salts; 
that is, they are true nourishers of plants. 
They afford, by the action of the growing plant, 
the same elements as the animal salts. Of this nature 
is saltpetre. Now, reader, I want you to understand 
by saltpetre, not only that well-known substance, but 
also that which has lately been much used in farming, 
South American saltpetre. This differs from common 
