212 



MANURES. 



Sect X. 5. 5. 



It Is probable that much phofphorus may beconfumed in our i 

 tificial mode of burning lime, which might be preferved by calcii 

 limeftone in clofe veflels, and thus detaching: the carbonic acid w 



o 



dmitting the aerial oxy 



the phofph 



b 



the ad 



of fuch a procefs can only be determined by exp 



m 



ages uncommonly 



Art. Agricult. 



There are many inftances given by Mr. Anderfon, and by Lord 

 Kaims, of foils which are faid to have been for 

 fertile without addition of manures or culture. Thefe are plains near 

 the fhore in the county of Caithnefs, and in the Hebrides, and are 

 faid to confift almofl: entirely of fliells broken into very fmall parti- 

 cles, without almoft any mixture of other foil. See Encyclop, Britan. 



Now the foil of an extenfive country called Lincoln 

 Heath I obferved fome years ago to confift in a great degree of pow- 

 dered limeftone, which like the Ketton limeftone appeared in fmall 

 rounded particles, which I fuppofe had in remote times been diflblv- 

 ed in water, and again precipitated ; which (hews a probable differ- 

 ence between this lime and recent (hells in refped to their antiquity, 

 and confequently that the former muft contain much of the original 

 phofphoric acid, and. the latter only carbonic acid. And as Lincoln 

 Heath was then efleemed a very unprodudive foil, there is reafon to 

 infer that the phofphoric acid in recent (hells is of greatly more fer- 

 vice to agriculture than the carbonic acid of alluvial limeftone, or 

 than calcined lime alone. 



Hence it is probable, that a greater quantity of phofphoric acid 

 may exift in fome marles than in others, as well as in fome limeftones; 

 thus the appearance of recent (hells exifts in the lime near Louo-hbo- 



rough in Leicefier(hii 

 marles called (hell-m 



in 



th 



road to 



Nottingham 



and 



in 



fome 



hich muft therefore probably 



much more phofphoric acid, fo as almoft 

 animals; and may thus be more friendly 



land is mentioned by Mr. Anderfon, that, after a thick coat of m 



2 



femble the bones of 



A piece of 



laid 



