$56 H U S B A 
but although good tillage, by feparating the foil, may bring 
a greater number of nutritious particles within the reach 
of the crop, yet the foil cannot poflibly continue to be fo 
completely divided as it is by the fermentation excited 
by dung and other manures ; which are found to enrich 
the belt pulverized foil again and again, after it is ex- 
liaulted by crops ; and therefore promote vegetation by 
inci’eafing the quantity of vegetable food. 
Every fubftance that, when laid on land or mixed with 
the foil, promotes vegetation, or increafes its fertility, is 
called a manure. Manures operate in all the different ways 
by which vegetation is promoted. By communicating to 
the foil with which they are mixed the vegetable food 
which they contain. By communicating to it a power of 
attracting this food in greater plenty from the air. By 
enlarging the vegetable pafture. By diffolving the vege¬ 
table food which it is already poffelTed of, and fitting it 
for entering the roots of plants. Some manures afford 
nourilhment only : as rape-dull, loot, rftalt-duft, pigeons’- 
dung, and in general all top or hand drelfings. Others 
give nourilhment, and alfo add to the foil; as animal 
dungs, and all rotten animal and vegetable fubftances. 
Others again open the foil, and do not nourish in their 
own nature : as lime, light marls, fand, &c. Laltly, other 
manures ftiffen the foil, and at the fame time nourifh a 
little : *as clay, clay-marls, and earth. 
Some manures lofe part of their ftrength by being long 
expofed to the air. Thus, after dung is fufficiently fer¬ 
mented, the longer it lies, the lefs is its value. Cow- 
dung dried on the pafture, gathered and laid upon other 
land, has fc.tvcely any effeCt; whereas the fame quantity 
carried from the cow-houfe, or collected by folding the 
cattle, enriches the land. Hence this kind of manure 
contains the vegetable food in itfelf, and does not receive 
it from the air. 
Other manures on the contrary operate fooner and with 
greater violence, the longer they are expofed to the air 
before they are ufed. Lime and marls are of this kind. 
They .are obferved to have a ftrong power of attracting 
certain qualities from the atmofphere ; and operate by 
communicating to the foil with which they are mixed a 
power of attracting vegetable food from the air. 
Again, fome manures exhauft land of its vegetable food, 
and do not reftore it again when immediately applied. 
This is thought to be the cafe with lime. Land tho¬ 
roughly limed, after having carried many very good crops, 
feems to be exhaulted, and reduced to a wori’e lituation 
than before. When in this cafe lime has been applied a 
i'econd time, its effects have been found to be far inferior 
to what they were when firft applied. This manure, there¬ 
fore, feems to operate by diffolving the vegetable food 
which it meets with in the foil, and fitting it for entering 
the roots of plants. It ought however to be remarked, 
that exhaiution "of land by lime is owing to bad manage¬ 
ment and unmerciful forcing of it with continued white 
crops. It is not certain that land will not bear a feconcWt 
liming. It is certain that the effeCt of the lime may be 
long kept up by the proper application of dung and other 
oily manures ; and there have been inftances of the effeCt 
of lime continuing forty, fifty, or even a hundred, 
years. 
Manures may be divided into fimple and compound. 
Simple Manures are inch as a rife from the agency or de- 
compofition of animal, vegetable, fofiil, Or faline, fub¬ 
ftances. Compound Manures, or Compofts, are fuch as 
arife from the combination of different fubftances. 
Of SIMPLE MANURES. 
Animal Substances. —Subftances of the animal kind, 
when reduced by the procels of putrefaction, or other 
means, into a foft, pulpy, or mucilaginous, ftate, are found, 
by the experience iff the molt correCf and able agricul- 
' tors, to afford thol'c'matters which are fuited to the nutri¬ 
tion and fupport of plants with greater readinefs, and in 
more abundance, than molt other bodies that can be em- 
N D R Y. 
ployed. By chemical analyfis it has been ft.own, that the 
component; materials of thefe fubftances, fo far as agricul¬ 
ture is concerned,\ are principally water, jelly, or. muci¬ 
lage, and fadeliarine oleaginous matters, with final! por¬ 
tions of faline and calcareous earthy fubftances. Hence 
animal matters, though they agree in fome circumftances 
with vegetable productions, each having in common wa¬ 
ter faccharine and calcareous matters, are far more com¬ 
pounded; and in animal fubftances, fome of thefe mate¬ 
rials are in large proportion, while in vegetables they only 
exilt in a very fmall degree ; and the jelly, which in lome 
meafure refer'nbles the gum and mucilage of plants, differs 
likewife from them, in its having much lefs tendency to 
become dry, as. well as in its property of attracting humi¬ 
dity from the atmofphere, and of running with great ra¬ 
pidity into the ftate of putrefaction and decay. All thefe 
principles of animal fubftances are relbl-ved by their ulti¬ 
mate decompofition into other masters, fuch as different 
gafeous fluids, carbon, phofphorus, lime, Sec. 
It would feetn probable, too, that in animal fubftances 
of different forts there may be differences in regard to the 
proportions of thefe feveral ingredients or principles. 
Some kinds affording one or more of them, in greater 
abundance than others ; while others again are deficient 
in theie, but abound in fome of the others. On this fup- 
pofition, the different effeCts of fubftances of the fame 
clafs, when applied t-o foils of the fame kind, may be eafily 
accounted for. - 
Animal fubftances of every kind, on being deprived of 
their vital principle, have a quick tendency to take on or 
run into the ftate of putrefaction, a procefs which is con- 
fiderablv affected and influenced by the circumftanc.es un¬ 
der which it is produced. But in the horny and more 
compaCt animal matters this tendency to putrefaction and 
decompofition is, under fimilar circumftances, much left 
rapid than in fuch as are of a lefs firm and denfe texture 
The procels of putrefaction is, however, greatly expe¬ 
dited by the conditions under which it takes place beiim 
favourable ; fuch as the fubftance, of whatever kind it 
may be, pollening fulficient moilture, being expofed to the 
free aCtion of atmofpheric air, and a moderate degree of 
heat. On various accounts it would likewife appear,that 
the decompofition of fuch fubftances may be promoted 
by mdiltening them with water llightly impregnated with 
common fait, and perhaps fome other faline fubftances 
fuch as the muriats of magnefia and foda, or fea-falt as 
ingenioully fuggefted by the earl of Dundonald. 
Dung is the molt common, general, and upon the 
whole the molt efficacious, of all manures. It is properly 
the excrement of animals, but is ufed alfo to ligniry all 
rotten vegetables, when ufed as manures. Dung pro¬ 
motes vegetation by increaling the vegetable food,\y en¬ 
larging the pafture of plants, by communicating to the 
foil a power of attracting the vegetable food from the air 
and by preparing the vegetable food for the nourilhment 
of plants. 
Dung of quadrupeds, is the molt common manure in 
life. Stable-dung is uibd either frelh or putrified; the 
firft is called long, the fecond Jkort , dung. It abounds in 
animal matter, eafily putrif.es, and ferves to halten the 
decay of other dead vegetable fubftances, Its fermenta¬ 
tion is promoted by frequent turning and expol'ure to the 
air; yet it fliould be covered to prevent water from car¬ 
rying off moll of its important ingredients ; or at leaft 
the water that imbibes them Ihould not be loft. Farm¬ 
yard dung confiits of various vegetables, chiefly ftraw 
lbinetim.es weeds, leaves, fern, &c. impregnated with ani¬ 
mal matter; it ferments more llowiy than ftable-dung, 
lhould.be piled in heaps, and ftirred from time time; fern 
in particular putrifies very llowiy. 
When any conliderable quantity of liable or yard dung, 
or other mixture of animal and vegetable fubftances,“ts 
collected together in a heap, and ferments ; when this 
procefs is completed, if the nia'fs be examined, we find 
that the vegetables of which it was originally compounded 
3 are 
