ADDITIONAL NOTES. 531

wbich is known to be fo friendly to vegetation, when applied to the roots of plants; and at the fame time a gypfum will be produced, which is now alfo believed to be ufeful in agriculture.

Mr. Kirwan afferts,‘ That the gypfum ufed with fuccefs in agri- culture is of a fibrous texture; and that clay lands, he believes, to be more improved by it than calcareous ones. The time of fpread- ing it is in February or March, and it is then to be thinly ftrewed on grafs-land at the rate of about eight bufhels to an acre; as more he fays would be hurtful. He further adds that the theory of its effets is to be deduced from its extraordinary fceptic power; as it is found to accelerate putrefaction. in a higher degree than any other fubftance,(Hiftoire de Putrefaétion, p. 36), whence it is not to be plouched in, but barely to be ftrewed on the furface of the land in the month of February, to convert the old grafs quickly into coal to nourifh the young growths.”

I have tranfcribed the above from Mr. Kirwan’s Treatife on Ma2- nures, but am liable to doubt the experiments concerning bodies promoting putrefaétion; as the progrefs of that procefs has generally been only judged of by the odour; which may poffibly be altered or deftroyed by many bodies, by their uniting with it without other- wife affe&ing the tendency to diflolution. Add to this another cir- cumftance, fhewing the uncertainty of thefe deduétions, that fome of thefe antifeptic materials, as fea-falt, and lime, are faid to pro- mote putrefaction, when ufed in fmall quantities; and to fupprefs

it, when ufed in larce ones,

ç. To be inferted in Set. XIH. 2. 2. at the end of the paragraph which mentions Mr. Lanwrence’s letter to Mr. Bradley.

. e« sic 7,= Another thing, which renders low fituations lefs proper for gar dens, is, that L believe them to be much more liable to be infefted

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