í to
illl
IIP
l i
lll:íl
T h e winds a t Mazatlan g en e ra lly blow fresh from the N . W . in the e v e n in g ; th e sea-
b re eze springs np ab o u t ten iu the forenoon, and lasts u n til two o’clock iu the morning.
I t is high wa te r a t this place a t 9 h. 50 in., full an d c h a n g e ; rise seven fe et sp rin g tide.
These are all the directions which i think it necessary to give in this place, as the ports
of Coquimbo and Valparaiso, at which the Blossom touched, are so easy of access, and so
well known, as to requite none; and Port Clarence and Kotzebue Sound, near Beering’s
Strait, to little likely to be frequented, and so free from danger, that it would be extending
the limits of this work nnnecessarily to add any thing on the subject. Besides, the charts of
those places which have been published since our return contain all that a vessel can require
for her guidance.
GEOGR.APHICAL POSITION OF PLACES VISITED BY H. M. S. BLOSSOM.
I n th e following T a b le th e longitudes have been determined by chronometrical measurements
between places fixed astronomically, o f which th e particula rs arc given below. Those
with an * affixed to them have been determined b y corresponding observations made a t observatories,
o f which th e longitudes are well known, and have been worked b y the formula
given by M r. F . Bailey in th e Memoirs o f the Astronomical Society, a gentleman who. is
entitled to the thanks o f nava l officers in p a rtic u la r, for this practical an d accurate method
o f determining th e longitude o f a place. T h e other results have been derived from the
observed rig h t ascension o f th e moon a t its tran sit compared with its computed place a t
th a t moment a t Greenwich, an d when th e transit has been found to deviate from th e meridian
th e effect o f parallax in A R has been computed for th e spheroid, b u t th e error arising
from this never amounted to 0" 5. T h e la tte r observations are liable to th e errors o f the
solar and lu n a r tables, and to still gre a te r inaccuracies, arising from tb e instability o f the
stand o f th e instrument. T h is was obliged to be made portable , and, owing to o u r short
stay a t every place, it was necessary to commence th e observations immediately, inconveniences
to which, I tru s t, my readers will a ttrib u te many o f th e discrepancies apparent
in tb e observations. In tb e whole course o f o u r voyage I obtained b u t fo u r occultations
o f fixed stars, o f which two were u n d e r such disadvantageous circumstances th a t th ey could
not give good results. T h e laborious method o f computing these observations has been much
simplified o f late by th e d a ta published in th e Nautical Almanac ; b u t when stars, not comprised
in those Tab le s, are observed, th e seaman will find an extremely simple method in th a t by
M r. E dw a rd Rid d le , who will, I hope, confer upon naval men th e benefit o f giving th is formula
a wider circulation th an it has a t present.
BIO JANEIRO.
T h e Observatory was erected in M r. M ay ’s garden, a t Gloria, 33" W . o f R a t Island, or
S5A" S. and 55" E . o f Villegagnon F o rt.
LONGITUDE. ’ LATITUDE.
1825.
July By culniin. moon,
compared with
Arcturus,
a Centauri, '
Spica,
a Scorpionis,
fT Sagittarii,
s Sagittarii,
a, Pegasi,
3 56
7 51
7 16
4 15 6 02
4 34
Longitude of Observatory, . . . 43 5 36 B
Diff. Long. . . . - 55
Longitude of Villegagnon, . . • 43 4 11 W .
Do. by 153 lunar distances E. and 57. 43 10 42 W.
Lat. 22 54 37 S.
Stars.
Ì 54 57.5 S.
5 09.6
5 22.6
5 03.7
4 57.3
5 14.5
5 22.5
5 06
5 07
5 16
4 50
5 28
5 36
5 29.4
5 21.2
5 sets by Lieutenant Wainwright, 43 10 39
Mean 22 55 11.12 S.
Latitude Villegagnon Fort, 22° 54' 37.5" S. Longitude, 43" 4' 41" W .