THE FAKMEr’s SfANUAL. 
25 
gelation ; hence the reason why plaster, when mixed 
with the seeds which are planted in the earth, gives 
the greatest vigour to vegetation ; because it imparts 
both its oxygen, and substance, to the absorbant ves- 
sels of the roots, and thus stimulates the vital princi- 
ples of those plants. 
All this is true as far as it goes ; and yet all this, 
without the heat of the sun, amounts to nothing ; and 
all this combined with the heat of the sun, amounts 
to hut very little, without the light of the sun : but 
the rays of light from the sun are not oxygen, nor elec- 
tricity, and yet they constitute one of the essential 
causes of vegetation, yet whal ctfects they produce, 
and how they produce them, are altogether concealed 
from our research, therefore 1 conclude as before, that 
one fact in good husbandry is worth two hypo- 
theses. 
Experience has proved gypsum to be one of the 
best manures, and taught us how to use it. 
From the Pennsylvania Farmer. 
“ Mr. Holbrook, of Derby. 
“ I have used gypsum, or plaster, for several years, 
as a manure. I have put many tons of it upon my 
own land, and have furnished my neighbours with it, 
both they, and 1, have derived great benefits from it. 
One of my neighbours sowed a quantity upon his up- 
land mowing, and his crop of grass was greatly bet- 
tered, as well as increased to three limes as much as 
the crop upon his adjoining land. 1 dressed a piece 
of land with it, on part of which I used to spread a 
run of water. Where the water was spread, I could 
not perceive that I derived the least advantage from 
the plaster, but the other part of the field produced 
white clover in abundance. I had four times the 
quantity of hay in proportion from the land dressed 
with the plaster, that 1 had from the land adjoining, 
on which none had been put ; and the land on whiA 
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