178 CORRESPONDENCE OF RAY. 



the 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 liquor, and six 

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

 have hitherto met with. 



The second layer was gravel, which reached from three 

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

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

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

 sooner than the former. 



The third layer was an earthy sand, which smells 

 stronger than the other two, and withal 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 liquor, 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 curiously 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 



