[ 340 ] 
Obfervers therefore fhould be flatloned farther to the 
Weft about Cape Corientes j at which place and at 
Mexico, though in about 20° of N. latitude, the ef- 
fedt of parallax will ftill be conftderable, particularly 
at the egrefs, as appears from the following Table. 
Places^ 
in- 
ternal con- 
taft. 
Second 
internal 
contaft. 
Total ef- 
feft of par, 
= 8 ", 7 - 
Difiercnce in 
tot. dur. from 
Tornea®, 
Mexico 
/ // 
/ // 
/ // 
// // 
I cy 
5 03 
6 10 
^7 50 
Cape Corientes 
0 26 
5 00 
5 26 
17 06 
By comparing the obfervations to be made at either 
of the above places, or in any of the neighbouring 
parts, with thofe of Tornea°, a difference of more 
than feventeen minutes in the total duration may 
commodioufly be obtained j by which the quantity 
of the fun’s parallax may be determined agreeably to 
the method propofed by Dr. Halley in the cafe of 
the laft tranftt, and in which no error but that of the 
obfervatibn cap take place, fuppofing the fituation of 
the two places to be nearly known. 
When D’r, Halley’s computation was examined, 
and it was found that fo great a difference in the to- 
tal duration of the tranfit at any two places as had 
been expetfed could not conveniently be obtained ; 
another method was propofed, and was accordingly 
carried into execution, viz. to ftation two obfervers 
in fuch a manner that one of the internal contadts 
might be obferved with the greateft difference poftible 
arifing from a contrary effedt of parallax at the two 
places. This method, though neceffarily inadequate, 
becaulc 
