222 GEOLOGICAL SURVEY 
under ordinary circumstances, it gives out carbonic acid, absorbs oxygen and nitrogen, forming a 
new product, to which Hermann has given the name of nitrolin, a Substance having nearly the 
same composition as flesh.* 
Nitrolin. Flesh. 
Carbots= oo. -22-=- 25 == eee 57.20__--55.20 
Eby nog ene: = ae see eee G:822=2- 17.00 
Nitrogen :2 = 2222 sSeeseeese ese 12:202- =-16.80 
Oxyren. of seese aera eee Sa se Se. 24.28. _ 21.80 
100.00 100.80 
It is the production of this highly nitrogenised substance that gives vegetable matter its fertili- 
zing power in the soil. During its decomposition it gives out carbonic and amonia to the soil, and 
is converted into dark colored substances, humine and humic acid. 
It is obvious, then, that the state of nitrogenization of the organic matter, is far more important 
than its quantity. 
Again, the analysis of a soil is not always an index to its fertility: when a soil is limed the fer- 
tilizing effects are not the result of the addition of any new ingredients, but are altogether due to 
the new combinations formed by those already existing in the soil, and which must have been 
detected by analysis. 'The lime, itself, enters but sparingly into the composition of plants. Hence 
fertilizing ingredients may exist in the soil, be indicated by analysis, and yet be entirely inert. 
The judicious agriculturist will not rest satisfied with the knowledge that his arable land con- 
tains all the components of fertility, but he will see that they exist under the proper conditions to 
exert their greatest influence on the products of the soil. 
I shall have occasion to show that a soil, from other causes, may be unproductive, at the same 
time that it may contain all the elements of fertility. 
To answer the expectations of agriculturists, analyses of soils must be multiplied far beyond 
what has yet been done, by having a chemical department attached to every geological survey. 
No one can suppose that 1000 grains of soil can fairly represent that of a whole plantation, how- 
ever carefully selected. Uniformity of soil, over a great extent, is only possible uuder certain pecu- 
liar circumstances, and, in the upper part of South Carolina, is not to be expected, even in the 
same field. 
There is one department in which chemistry has fully redeemed its pledge to agriculture—the 
analysis of the products of the soil and of manures. Plants analyze soils most accurately, and 
whatever of inorganic matters they contain must be found in the soil. And if we continue to 
abstract these matters, by repeated cropping, and without making any return, sterility must be the 
result. Inowing, then, the composition of each crop, we know what is removed from the soil; and 
knowing also the composition of the manures within our reach, we know what to apply. This is 
absolute knowledge, and must constitute the basis of every enlightened system of agriculture. We 
must, by proper tillage, take care that as little as possible escapes from the soil, excepting through 
the medium of the crops. 
When, after a succession of crops, and consequent abstraction of a large amount of its salts, the 
* Kane’s Industrial Resources of Ireland. 
