26 On Plaister of Paris. 
Answer. By the experiments and observations which 
I have made, I find a high, warm, dry, gravelly or loamy 
soil, to be much the best ; clay, cold or low lying land, 
is seldom favourable for it. I have known some low 
lying land which was dry and loamy agree with it, but 
not near equal to the high. 
Query 5. Have you repeated the application of it 
with or without ploughing—at what intervals, and with 
what effect ?* 
Answer. 1 have frequently repeated the use of it both 
with and without ploughing. I sowed a field with it five 
years ago, which had some little appearance of both 
red and white clover, but had never been sown with 
any seed, upon which I put one and a half bushel of 
plaister per acre. I pastured the field, and although the 
season was very dry, it produced a great quantity of 
good pasture sufficient to keep about one and an half 
head per acre. The second year I sowed one bushel 
more peracre. The season being more wet, it was bet- 
* The effects of the plaister detailed in this answer are in- 
variably proved by all experience, before and since this pub- 
lication. When I mentioned the operative principle of the 
plaister—i. e. the sulphuric acid (first set free itself, and then) 
decomposing substances in the earth, and thereby furnishing 
their food to plants and attracting moisture, the idea was 
either new, or little known. But it accounts for all the phe- 
nomena of plaister. Old fields are uniformly found to evi- 
dence the strongest effects. In them, decayed roots, and ve- 
getable putrefying or putrefied matter, is in the greatest 
abundance. 
R. P. 
September, 48f0. 
