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TALCAHUANA.
Observatory 8’ E . and 19» S. o f F o rt St. Augustine.
LONGITUDE. - .
Oct. By culmin. raoon,
14. compared with Arcturus,
16..................................................... a. Aquarii, ^
/3 Aquarii, )
1 8...................................................... Aquarii,
1 9.............................................................Aquarii,
Difference of Longitude,
Longitude F ort St. Augustine,
72 54. 34 W .
56 06
Sun.
36 42 41 S
42 51
42 54
36 42 53.2
36 42 54
by 100 lunar distances © and .
on the spot, and 101 0 IV.
Sea, referred by chronometer,
© 5V. and « E. by Lieut. IVain-
wright,
,3
ï> J
Sun
Stars
Mean 36 42 53.6
Diff. Lat. — 19
Lat. 36 42 34.6 S.
o St/a rs.If
36 43 03 S.
43 10
43 12
42 51
42 46
42 47
42 44
42 50
42 46
42 45
42 58.5
43 01.5
- 73 08 55 5V. 35 43 54 g_
Latitude Fort St. Augustine, 36" 42' 35" S. Longitude, 72° 56' 59" W .
T h is re su lt differs ab o u t 3' from my observations a t Coquimbo in 1828 referred back by
chronometers. A s those observations were made u nder more favourable circumstances, o f
which hav in g a firmer stand for th e transit was not th e least, I th in k th ey are nearer th e tri’ith.
These place F ort St. Augustine in l o n g i t u d e , ..............................................73 01 17 W.
B o th , however, are liable to th e errors o f th e lu n a r tables. I n the
geographical table which follows,' I have deduc ed the longitudes o f pl.aces
between F o r t S t. A u g u stin e a n d P itc a irn island from my observations in
1826 ; b u t i f th e re su lt o f transits in 1828 should hereafter prove correct,
th e proportion can re adily be added.
BOW ISLAND.
Observatory \ 2" N. 55" W . of d um p o f cocoa-nut trees a t N. E . extreme of the Island,
or r 35" S. and 5' 18" E . o f th e morai a t the entrance o f the lagoon.
LONGITUDE.
By culmin. H,
compared with Aldebaran,
. Pollux, .
. oe Leonis,
140 51 45 • Greenwich.
140 51 25 «Greenwich.
Mean,
Difference of Longitude,
Longitude of N. E . cluster of cocoa-nut trees,
do. by lunar observations © and * E. and 5V.
on the s p o t , .........................................
do. do. referred liy chronometer from observations
a t Byam Martin island.
Mean,
Difference o f Longitude,
do. by Lieutenant Wainwright on Byam Martin
island, referred by chronometer.
140 51 50
140 51 40 W.
ide’ -25
140 51 15
d
140 49 24
- ?
5
140 51 36
140 50 28.5
le] •25
140 50 03 W.
Mean,
Diff. Lat.
LATITUDE.
^Stars.
3 8 6 15 S.
6 32
6 05
6 14.5
6 03.5
6 11.5 6 00
5 52
5 58
5 59.5
6 0.3
5 .54
fi 24
5 55
18 6 06 S.
+ 12
140 56 20 W.
B y L ieutenant W a inw rig h t, meridian altitude 0 , 18 Ofi 20 S.
Latitude of N . E. clump of cocoa-nut trees, 18" 6' 18’’ S. Longitude, 140’ 5 1 ' 15" VV.
OTAHEITE.
Observatory a t Toanoa S' 42'' W . o f P o in t Venus.
April 16. Longitude by culmination of moon compared with i
Longitude Point Venus,
Longitude by lunar observations, © East,
do. by Lieutenant Wainwright, © a
Leonis, 149 34 45 W.
Leonis, 33 40
Leonis, 35 06.0
Greenwich.
Greenwich.
Greenwich.
149 34 50
- 3 42
149 32 39 W.
149 28 58 W.
I considered P o in t Venus so well fixed by Messrs. Wa les an d Baily, that I took !
pains to determine its position dian I bestowed upon o th e r places, an d I have given only the
results o f transits o f the moon, to which corresponding observations have been obtained.
I t was extremely satisfactoi-y to find, on o u r arrival a t th is place, th a t th e chronometrica 1
measurements between Ta lc ah u an a and Otaheite, on which th e positions o f so many islands
depended, agreed very nearly with th e differences o fth e meridians by astronomical observations.
Thus, the difference of longitude between Talcaliuana and Pitcairn
island, by Talcahuana r a t e s , ...................................................
Between Pitcairn and Gambier islands, by Pitcairn island rates,
Gambier and Bow islands, by the same rates.
Difference o f meridians.
Longitude of Talcahuana,
gitude of Bow island.
Difference o f longitude by the same rates.
Longitude of Observatory at Otalieite,
Point Venus, east of Observatory,
Longitude of Point Venus by chronometer,
by observation.
T h e positions of th e islands o f the Low Archipelago may, therefore, be considered nearly
accurate, with tho exception o f th e errors avi.sing from observations unavoidably made over
the sea, as it was impossible to land upon many o f them ; and o f those ensuing from th e d ifficulty
o f determining tbe la titu d e accurately witii a nearly vertical sun, a t which time even
the method o f 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 th a t both latitudes and longitudes are veiy
nearly correct.