129 
OF GARDENING AS A SCIENCE. 
NO. VI. 
We have thus far followed Dr. Liebig in his leading principles of chemical 
philosophy, as applied to the nutriment of vegetables : his last great proposition 
we have seen to be this — that plants derive their nutriment chiefly from the at- 
mosphere ; during and by which process they purify the air, absorbing that gas 
which would otherwise so accumulate as to become destructive to every being 
endowed with powers of respiration. 
The hypothesis is startling, because it impugns those ideas which have been en- 
tertained by us all respecting the source and channels of the nutrimental sap. It 
remains, then, to investigate a little more minutely the agency of manures , and to 
discover, if it be possible, or at least to obtain a glimpse of the effects which they 
produce upon plants in the different stages of their growth. By manure we wish 
it to be understood that we mean to express every substance, without any ex- 
ception whatsoever, which is decomposable in soils, and capable of being resolved 
into the elements of water, (oxygen and hydrogen,) of carbonic acid, (oxygen and 
charcoal, or carbon,) and of ammonia (hydrogen and nitrogen). 
We make no allusion to manure in its limited sense, as applied agriculturally, 
but look at it broadly in its most simple, equally as in its most complicated form ; 
and therefore, to make a commencement, we refer for example to that most feeble 
of all substances employed by the gardener, now usually styled peat, but which was 
formerly called bog earth. 
This black-greyish or brown soil consists chiefly of white silicious sand, mixed 
with varying portions of fern, bog-moss, (sphagnum.) heath-leaves, rushes, or similar 
matter, in a condition of progressive decay. We lately visited the country about 
Virginia Water, Sunning-hill, and the border of Berkshire, south of Windsor Forest ; 
and saw masses of this w T eak, black earth, cut out of common grass land, and laid 
up in heaps to mellow. It is tempting to those who delight in what are termed 
the American tribes of plants to behold this store of native soil ; but w T oe be to him 
who shall touch it in its pristine state, as it is thus turned up to light ! Buried in 
the darkness of ages, swamped with water, and of a butyraceous, compact texture, 
it is incapable of affording support to any plant but the poor miserable herbage 
which pines upon its surface. Yet this crude earth is a mine of manure, and by the 
operation of air, light, and atmospheric electricity, it is meliorated, and becomes 
qualified to support all the hair-rooted tribes which now are the prime ornament 
of our best gardens. The nurserymen in that quarter, who are ignorant of chemical 
principles, say that their customers complain of the loss of plants, although they are 
at pains to procure the best true soil. But in what state do they use it ? as fresh, 
of course, as possible ; and the consequence is inevitable — 44 it burns every root it 
touches.” 
VOL. vm. — no. xc. 
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