[ 533 1 
intelligence, fay, they never knew, in forty to forty- 
five years obfervation folow a tide, by full two feet • 
you may depend on the winds having been ftronger 
to the S.W. below than here. 
William Mitchell. 
To the Rf. Hon. George, Earl of Macclesfield, Pre- 
Jident oj the Royal Society. 
My Lord, 
Read Mar. i i,TN obedience to your lord fh ip’s com- 
I mands, I have informed myielf more 
particularly what Hare the waterman related, con- 
cerning the late irregularity of the tide, in the paper 
I had the honour to lay before the Society laft Thurf- 
day, which is as follows. 
That Hare going down the river the 13th pafl 
with the current, lie met an unexpected flack in 
Greenwich-reach. Soon after, as he proceeded, the 
current regained its force ; but about three miles 
lower, in a reach called Bugby's-hole, he met again 
another flow or flack water ; and before he got to 
Woolwich, which is about three miles lower, the 
current regained its force, and continued running 
down fome time after ; whereas, according to the 
tides, had they been regular, it ought to have been 
low water before the time he got to Woolwich. 
By enquiring more circumftantially relating to this 
phenomenon, that as the wind then prevailed pretty 
hrong at W.N.W. and N.W. in all probability the 
wind might make a fudden fhift, which caufed thefe 
hidden impulfes or eddies : but this I fubmit to your 
Vol. 45). Yyy lord- 
