tants were oblig’d every day, to drive their cattle ſeveral miles, for watering. The drought was greater, than has been known in the memory of any one living. This ſhows how fit the dry ſurface was, for an electrical vibration. And we learn from hence, this important particular, that it reaches but very little below the earth’s ſurface.
Mr. Johnſon, in another letter which he wrote to me concerning the ſecond earthquake obſerv’d at Spalding; ſays upon this occaſion, he was obliged to ſcour his canal, and deepen it: that they came to a white, quickſand; which afforded to all the neighbourhood, excellent water in plenty.
In the gravelly ſoil of London; and where the two ſhocks were felt by us, in the beginning of the year; we know, there is not a houſe in the whole extent of this vaſt city, and all around it, but a ſpring of water is ready, upon digging a well. Whence we have much reaſon to believe, that the interior of the earthy is like a ſponge ſoak’d in water. So that the only dry part is the ſuperficies, which is the object, and the ſubject of that electric vibration; wherein, according to my ſentiments, an earthquake conſiſts.
This ſhews the miſtake of the ancients, who fancying that earthquakes proceeded from ſubterraneous eruptions, built their prodigious temple of Diana at Epheſus, upon a boggy
ground,
