C 297 j 



sum could not have been artificially furnished, I could 

 not detect any of this substance in it; and at the very 

 time I collected the soil, the peat-ashes were applied 

 to the clover in the field. The reason why gypsum is 

 not generally efficacious is probably because most 

 cultivated soils contain it in sufficient quantities for the 

 use of the grasses. In the common course of cultiva- 

 tion, gypsum is furnished in the manure; for it is con- 

 tained in stable dung, and in the dung of all cattle fed 

 on grass; and it is not taken up in corn crops, or crops 

 of peas and beans, and in very small quantities in 

 turnip crops; but where lands are exclusively devoted 

 to pasturage and hay, it will be continually consumed. 

 I have examined, four different soils cultivated by a 

 series of common courses of crops, for gypsum. One 

 was a light sand from Norfolk; another a clay bearing 

 good wheat from Middlesex; the third a sand from 

 Sussex; the fourth a clay from Essex. I found gyp- 

 sum in all of them; and in the Middlesex soil it amount- 

 ed nearly to ore per cent. Lord Dundas informs me, 

 that having tried gypsum without any benefit on two 

 of his estates in Yorkshire, he was induced to have 

 the soil examined for gypsum according to the pro- 

 cess described in the Fourth Lecture, and this sub- 

 stance was found in both the soils. 



Should these statements be confirmed by future 

 enquirers, a practical irif .rence of some value may be 

 derived from them. It is possible that lands which 

 have ceased to bear good crops of clover, or artificial 

 grasses, may be restored by being manured with gyp- 

 sum, I have mentioned that this sub.stance j s found 



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