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ammoniacal salt it contains. The liquor produced 
by the distillation of coal contains carbonate and 
acetate of ammonia, and is said to be a very good 
manure. 
In 1808, I found the growth of wheat in a field 
at Roehampton assisted by a very weak solution of 
acetate of ammonia. 
Soapers’ waste has been recommended as a ma- 
nure, and it has been supposed that its efficacy 
depended upon the different saline matters it con- 
tains ; but their quantity is very minute indeed, 
and its principal ingredients are mild lime and 
quicklime. In the soapers’ waste from the best 
manufactories, there is scarcely a trace of alkali. 
Lime moistened with sea-water affords more of this 
substance, and is said to have been used in some 
cases with more benefit than common lime. 
Mr. Knight informs me, that he has found, in the 
two last seasons, that pond mud, of very poor 
quality, chiefly clay, having been mixed with coal 
dust, to afford fuel for his hot-houses, afforded a 
manure of considerable power. It acts, however, 
much more beneficially upon soils which are in 
tolerably good condition, and perhaps rather sti- 
mulates than feeds *, for on very poor soil, where 
some was laid in the last winter, its effects can 
scarcely be perceived. 
It is unnecessary to discuss to any greater extent 
the effects of saline substances on vegetation ; ex- 
cept the ammoniacal compounds, or the compounds 
containing nitric, acetic, and carbonic acid ; none 
of them can afford by their decomposition any of 
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