386 Mr . N. Pigott’s Obfervation of 
the earth, the effects of parallax muft be confiderable, and the* 
weftern fituation of Greenwich of 1 8' in time from this 
place, muft occafion a retardation, which, on computation, 
may be hereafter allowed for, and added to the fuppofed time of 
the egrefs above-mentioned, deduced from my obfervation here. 
While I am writing this Paper, the refpedtive fituation of 
Greenwich and Louvain ftrikes me. The latitude of Green- 
wich is 51 0 28' 40", that of Louvain 50° 53 / f'*; the dif- 
ference little more than half a degree. Greenwich is f 1 6" 
weft, and Louvain f 37" eaft of the Paris Obfervatory ; the 
parallax above-mentioned is therefore nearly, but in a contrary 
fenfe, equal at the two places, and thus the effects of both are 
compenfated relatively to Paris. What other advantage may 
refult from this circumftance, would require confideration. I 
have not leifure, at prefent, to revolve it in my mind, as I am 
defirous to lay this Paper before the Royal Society as foon as I 
can, by the favour of Dr. Maskelyne, our Aftronomer Royal. 
♦ See Phiiofophical Tranfa&ions, vol, LXVIII. p. 643. 
Obfervations 
