] 78 COKRESPONDENCE OF RAY. 



tlie smell and other qualities to this layer. This clay 

 preserves its scent a pretty while, though by degrees it 

 grows fainter ; and being exposed to the air for about a 

 month, will lose it quite. Eight pounds of this clay dis- 

 tilled in a retort, placed in a sand-fire (third degree of 

 heat), yielded one pound of phlegmatic Hquor, and six 

 drachms of oil, of a quite different smell from anything I 

 have hitherto met with. 



The second layer was gi-avel, which reached from three 

 and a half to about four and a half deep, or thereabouts. 

 It very much resembles the other in ah its qualities, ex- 

 cept the noisomeness of its smell. It loses its scent much 

 sooner than the former. 



The thu-d layer was an earthy sand, which smells 

 stronger than the other two, and Avithal is much more 

 fragrant. The deeper you dig it smells the stronger. I 

 took eight pounds of this layer, at nine feet deep, and 

 filled a retort with it, and placed it as the clay ; but it 

 afforded only six ounces of phlegmatic Hquor, and two 

 drachms of oil. This sandy loose earth quits its scent in 

 about a fortnight, being exposed to the summer air. 



Considering that waters owe their greatest differences 

 to the several soils through which they pass, I was very 

 desirous to see what sort of waters would be produced 

 by their being percolated through such a strainer as this 

 strange sort of earth ; and desiring the owner to dig till 

 he should find water, he accordingly did ; and when he 

 came to about eighteen feet deep, water came in very 

 plentifully, conditioned as follows : — 



It had at top a cmiously coloured film, the colours of 

 it resembling those of the rainbow. Under this was a 

 whitish-coloured water, which, upon standing in a phial 

 some days, lets fall a brownish sediment, and by that 

 means becomes diaphanous. It smelt very strong, as the 

 earth did ; was somewhat bitter and clammy, as one may 

 see by putting his hands in it, and suffering them to dry 

 without wiping. If you put some powdered galls into a 

 glass of this water, so soon, or a little after, you take it 



