LIQUID MANURES CHEMICALLY APPLIED 
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)mparison with the well-defined proportional alliances of ordinary chemical com 
Dunds. But independently of purely organic structure, plants endowed with life 
itrosuscept a great number and variety of purely chemical, inorganic salts, and 
lose chiefly from the soil. 
The earths proper — of metallic origin — are also to a certain extent absorbed and 
, eposited in certain specific conditions, varying according to the peculiar tempera- 
i lent of the vegetable subject. 
If, then, any liquid manure is found to produce a marked effect upon a plant, 
! lat effect must depend chiefly, if not entirely, upon the salts which it holds in a 
fcate of aqueous solution ; therefore, in order to understand the mode in which any 
iven solution can act, we must submit it to correct analytic experiment. Let us 
ake for the type that compound fluid which results from a portion of the best and 
urest Bolivian guano ; for there we detect nearly all the elements which are 
raceable in the saline product of organised vegetable life. The soluble salts of 
uch guano are sulphates of potass, of soda, and of ammonia ; muriate or chlorides of 
3da and ammonia ; phosphates of ammonia, &c. ; and also a quantity of free urea. 
Ve do not pretend to determine the proportions or exact quantities of those salts, 
he variableness of guano being proverbial ; but that they all, or most of them, are 
resent, in certain proportions, may be considered an admitted general fact. The in- 
oluble components of good guano consist chiefly of the bone phosphate from fish, 
i educed to a state of division so minute as to defy comparison — of urate of ammonia 
-of ammonio -phosphate of magnesia — and of some other minor ingredients, 
I mong which we have detected an oxide of iron, and a quantity of organic matter, 
hat represents, as nearly as may be, the compound which of late has been termed 
umus, since it is destructive by fire, excepting that small portion of siliceous sand 
diich most samples of guano are found to contain. 
If, then, guano be employed as liquid manure, it is plain that every plant must 
|>e injured, unless it be constitutionally inclined to imbibe and receive nutriment from 
he salts contained ; and even then the solution should be exceedingly weak, and be 
used with discretion. 
Potter’s guano appears to combine sulphate of ammonia as its chief active in- 
gredient, common salt in smaller proportion, a quantity of powdered chalk (these 
wo susceptible of mutual attraction), a little vegetable alkali, and much bone-dust, 
.tis not guano, but a very useful dress for the farm, — and the liquid will contain the 
;alts named, with the addition of some free ammonia, owing to the action of the 
ootash upon the sulphate. 
If steeped manures — as sheep-dung, horse-droppings, cow’s, deer’s, or pigeon’s - 
lungs — be used, in a state of fermentation, a peculiar saline matter may be present, 
vhich, in all probability, will be most correctly called humate of ammonia , a 
.'ompound that claims the strictest attention, and which we shall now attempt to 
describe. 
This salt of ammonia is produced by the attraction or chemical affinity which 
