[ 59i ] 
water, chiefly {hewing what might create any degree 
of uncertainty in the obfervations. Some of the al- 
titudes are marked with 2 dots thus : and fome with 
4 thus :: . The firft mark is to (hew that the alti- 
tudes are to be efteemed doubtful on account of cir- 
cumftances attending them : and the fecond mark is 
to {hew that they are very doubtful. 
I fhall fay nothing with refpedt to any conclufions 
that may be drawn from the above obfervations, ex- 
cept that the greateft rife and fall of the water, that 
I have obferved, at the fyfigies of the Sun and Moon, 
is about 13 divifions of the poll or 39 inches, and 
that the fmalleft rife and fall in the quadratures, is 
fomewhat lefs than 7 diviflons of the poll, or about 
20 inches ; and that the mean time of high water 
happens 2 h 15“ after the Moon’s pafling the meri- 
dian, though in the courfe of every fortnight the faid 
interval is very much varied by the different influence 
of the fun at different times, as the theory requires. 
I am, Sir, 
Your moft obedient, 
St. Helena, Jan, Humble fervant, 
26, 1762. 
Nevil Mafkelyne, 
4 G Oh* 
Vol LSI. 
