PN teRO DUE LON: XXX

impropriety, barely mention, that from the ap- plication of this principle, many phenomena may be explained in a very fatisfa€tory manner, which have been hitherto reckoned cafes of great difficul- ty. Some of thefe,(particularly in the ae of a well that was funk at Tilbury Porton the—lhames, as narrated in the Phil. Tran. Vol. in which an abundant{pring of fresh water was found, at a great depth below the furface. of the fea, after two fprings of /alé water had been] afled through above it,) I pointed out, in a letter I did myfeif the honour to write, feveral months ago, to Leigh Philips, Efq. of Manchefter, who had been kind enough to fay that the eflay referred to was what he conceived to be a compleat fyflem of draining. This expreffion induced me to fhow him it could not be deemed compleat; as feveral cafes were omitted, which I then fpecified to him: among others, it: was fhown that deep. lakes,— fur- rounded by mountains of great height on all fides, may, on fome octafions, be entirely drained, by boring, or finking fhafts downwards, fometimes :

to a moderate depth: that alfo wet land may >

7

on fome occafions, be more eafily drained, by

opening an outlet for the water benéath the re-

fervoir which Oc cafions the Vet tha in by b br rins- 5

ing it up tothe fu‘face. And that, among moun-