GEOGRAPHICAL POSITIONS. 
665 
OTAHEITE, 
Observatory at Toanoa 8' 42" W. of Point Venus. 
1826. ° f II 
April 16. Longitude by culmination of moon compared with a. Leonis, 149 34 45 W. • Greenwich. 
a Leonis, 33 40 * Greenwich. 
Leonis, 35 06.0 • Greenwich. 
149 34 SO 
—3 42 
Longitude Point Venus, I49 31 08 W. 
Longitude by lunar observations, © East, .... 149 32 39 W. 
do. by Lieutenant Wainwright, © and • E. and W. 149 28 58 W. 
I considered Point Venus so well fixed by Messrs. Wales and Baily, that I took less 
pains to determine its position than I bestowed upon other places, and I have given only the 
results of transits of the moon, to which corresponding observations have been obtained. 
It was extremely satisfactory to find, on our arrival at this place, that the chronometrical 
measurements between Talcahuana and Otaheite, on which the positions of so many islands 
depended, agreed very nearly with the differences of the meridians by astronomical observations. 
Thus, the difference of longitude between Talcahuana and Pitcairn 
island, by Talcahuana rates, 
Between Pitcairn and Gambier islands, by Pitcairn island rates, 
Gambier and Bow islands, by the same rates, .... 
0 / n 
. 57 11 13 
4 46 58 
. 5 55 57 
Difference of meridians. 
Longitude of Talcahuana, 
. 67 54 08 
. 72 56 59 
Longitude of Bow island, .... 
Difference of longitude by the same rates. 
. 140 51 40 
. 8 42 24 
Longitude of Observatory at Otaheite, 
Point Venus, east of Observatory, 
149 34 04 
—3 42 
Longitude of Point Venus by chronometer. 
149 30 22 W. 
by observation. 
149 31 08 W. 
The positions of the islands of the Low Archipelago may, therefore, be considered nearly 
accurate, with the exception of the errors arising from observations unavoidably made over 
the sea, as it was impossible to land upon many of them ; and of those ensuing from the dif- 
ficulty of determining the latitude accurately wdth a nearly vertical sun, at which time even 
the method of circum-meridian altitudes becomes very uncertain. I endeavoured always to 
avoid these by connecting morning and afternoon observations by triangulation, and as they 
never differed materially, I have reason to think that both latitudes and longitudes are veiy 
nearly correct. 
