663 
GEOGRAPHICAL POSITION OF PLACES VISITED BY H. M. S. BLOSSOM. 
In the following Table the longitudes have been determined by chronometrical measure- 
ments between places fixed astronomically, of which the particulars are given below. Those 
with an * affixed to them have been determined by corresponding observations made at ob- 
servatories, of which the longitudes are well known, and have been worked by the formula 
given by Mr. T. Bailey in the Memoirs of the Astronomical Society, a gentleman who is 
entitled to the thanks of naval officers in particular, for this practical and accurate method 
of determining the longitude of a place. The other results have been derived from the 
observed right ascension of the moon at its transit compared with its computed place at 
that moment at Greenwich, and when the transit has been found to deviate from the me- 
ridian the effect of parallax in AR has been computed for the spheroid, but the error arising 
from this never amounted to O'' 5. The latter observations are liable to the errors of the 
solar and lunar tables, and to still greater inaccuracies, arising from the instability of the 
stand of the instrument. This was obliged to be made portable, and, owing to our short 
stay at every place, it was necessary to commence the observations immediately, inconve- 
niences to Avhich, I trust, my readers will attribute many of the discrepancies apparent 
in the observations. In the whole course of our voyage I obtained but four occultations 
of fixed stars, of which two were under such disadvantageous circumstances that they could 
not give good results. The laborious method of computing these observations has been much 
simplified of late by the data publi.shed in the Nautical Almanac ; but when stars, not comprised 
in those Tables, are observed, the seaman will find an extremely simple method in that by 
Mr. Edward Riddle, who will, I hope, confer upon naval men the benefit of giving this for- 
mula a wider circulation than it has at present. 
EIO JANEIRO. 
The Observatory was erected in Mr. May’s garden, at Gloria, 33" W. of Rat Island, or 
35i" S. and 55" E. of Villegagnon Fort. 
LONGITUDE. 
1825. 
July 
20 . 
21 . 
22 . 
23. 
27. 
28. 
31. 
By culmin. moon, 
compared with 
Arcturus, 
5 Centauri, 
Arcturus, 
/3 Centauri, 
Spica, 
a Scorpionis, 
T Sagittarii, 
£ Sagittarii, 
a Pegasi, 
43 
/ n 
5 15 
3 56 
7 51 
7 16 
4 15 
6 02 
4 34 
Sun. 
Longitude of Observatory, 
43 
5 36 
Diff. Long. 
— 55 
Longitude of Villegagnon, 
43 
4 41 W. 
Do. by 153 lunar distances E. and W. 
43 
10 42 W. 
Do. 5 sets by Lieutenant Wainwright, 
43 
10 39 
O 
/ 
ft 
22 
55 
24 
S. 
26 
15 
12 
00 
22 
55 
15 
22 
55 
11. 
1 
Mean 22 
55 
13 
s. 
Ditf. Lat. 
— 
35. 
5 
Lat. 22 
54 
37 
s. 
LATITUDE. 
Stars. 
“ r n 
22 54 57.5 S. 
5 08.7 
5 05.2 
5 03.2 
4 52 
5 09.6 
5 22.6 
5 03.7 
4 57.2 
5 14.5 
5 22.5 
5 06 
5 07 
5 16 
4 50 
5 28 
5 36 
5 29.4 
5 21.2 
Mean 22 55 11.12 S. 
Latitude Villegagnon Fort, 22° 54' 37.5" S. Longitude, 43° 4' 41" W. 
