[ 3+2 ] 
In order to fee the beginning of egrefs accelerated 
by the greateft effedt of parallax poffible, when the 
altitude of the fun is 5°, an obferver mud: be ftationed 
in about 123'" of Weft longitude from London, and 
in about 19° of S. latitude; or, as it does not appear 
at prefent that there is land there, the obferver may 
be ftationed with confiderable advantage either in the 
iflands of Mendoza, or in the ifland of St. Peter. The 
fame contact will be as much retarded on account of 
parallax to an obferver placed under the tropic of 
Cancer, in about 67° of E. longitude from London. 
Th is point indeed falls into the Gulf of Sindi j but as 
a difference of many degrees, either in longitude or 
latitude, will occafion but a very inconfiderable dif- 
ference in parallacftic time, this contact may be very 
advantageoufly obferved on any part of the coalt 
from the mouth of the Indus to Cape Comorin, 
and from thence along the coaft of Coromandel and 
Golconda as far as the mouth of the Ganges. It 
may naturally be expedted thk the end of the tranfit 
will, if the weather be favourable, be obferved at 
many of our own fettlements in thefe parts : I have 
therefore computed the effedl of parallax at the egrels 
for Madrafs and Calcutta, at which places the laft 
tranftt was obferved ; and find that the time of the 
fecond internal contadt will happen 6' 41" later on 
account of parallax at the former, and 6' 44 ' at the 
latter, than if feen from the earth’s center. By com- 
paring the obfervations made at either of the above 
places with the correfponding obfervation at Mexico, 
we may obtain a difference of 1 1' 44^' ; a difference 
greater than could be obtained by any obfervations 
that could conveniently be made at the egrefs in the 
tranfit of 1761. 
Upon 
