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nxtraB 0/ L E T T E R XX. 
From the Honourable and Rev, Hr. Spencer Cowper, 
^ean of Durham, to his Brother the Right Ho- 
fiourable William Karl Cowper, F. R. S, 
Durham, near the City. 
Read Jan. 15, X T P 6 N acquainting Mr, Gowland 
’ L/ with Lord Willoughby’s defire of 
being acquainted with the circumflances of the com- 
motion of the water in his pond on the firfi: of No- 
vember laft, he came to me the other evening with 
his gardener, who gave the following account : 
I'hat on the firfi; of November, about half an 
hour after ten in the forenoon, as he was working in 
his mafter’s garden, he was alarmed by a hidden 
ruihing noife, like the fall of water : That imagin- 
ing the head of the pond to be broken down, which 
was at a fmall difiance from him, he ran hafiily to- 
wards it, and finding it firm and in tire, was a good 
deal at a lofs to account for the noife he had heard; 
when, calling his eye upon the water, he faw it gra- 
dually rife up, without any fludtuating motion, till 
it reached a grate, which flood fome inches higher 
than the common water-level, through which it dif- 
charged itfelf for a few feconds : That it then fub- 
fided as much below the mark it rofe from, as it 
was above it in its greateft elevation ; and continued 
thus rifing and falling all the time he ftood by it, 
which was, he reckons, about fix or feven minutes, 
making four or five returns in about one. At lafi: 
* At Mr. Gowland’s feat, five miles from Durham. 
VoL. 45>. D d d 
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