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ASTRONOMICAL OBSERVATIONS.
TO THE EDITOR.
Sir-I dare say many of your readers lwsides
in} self felt somewhat annoyed in not baing able to
witness the eclipse of the moon on Wednesday
evening on account --f the clouds. In a scientific
point oi view mis was oi no importance; uut i can
suppose that in certain cases the overshadowing of
a i- loud might be a real if uot an irreparable mis
fortune, lam induced to think so from a state
ment of Mr. Hind, Astronomer Royal of England,
recently published by you, In which he expresses u
hope 'that all the resources of modern science
and all the facilities afforded by modern enter
prise will be combined.' no as to aflbrd the greatest
possible facilities for determining tho distance of
the sun from the earth, by means of observations
of the transit of Venus in lS74und 18H2.
If I understand the subject aright, the computed
distances of all lhe planets, nnd even those of the
fixed stars whose parallaxes aic known, depend
upon the accuracy with which the dixtancc of the
sun can be ascertained ; the latter being thu unit
from which the distances of the plaueU are deter
mined in accordance with Kepler's third law, and
the base-line employed iu the great survey of the
ttellar universe. 1 also understand that the best
possible mode known to astronomers of computing
the sun's distance is by ascertaining with ail
possible prccishn the length of time occupied by
the planet Venus in traversing the muu'h disc, aa
seen from different Positions on the earth's sur
face, the exact latitude and longitude of which are
known.
Uut as the transit of Venus is of exceedingly
rare occurrence, and, as stated by you in the para
graph to which i have referred, that of December
!), 1874. will be visible in all the Australian Colo
nies, but invisible to the inhabitants of western
Europe, a question of great importance to scicuco
arises namely, as to the best localities for taking
the necessary observations; or, in other words,
where within the continent of New Holland can
the astronomer fix his instrumcntx with anything
like confidence that the atmosphere will not be
clouded when the transit takes place!
The great desideratum is an unclouded iky.
Can this be secured by ascending the Australian
Alps! by penetrating into the and regions ot tho
interior? by balloon ascents, or by any other
means ! Sonic of your readers better acquainted
with the .subject than lnyHelf may perhaps be in
duced to answer this (|iicstion, and iIiub confer a
real benefit to the cause of science.
It may be thought premature to discuss this
subject, but it is evident that tbe Astronomer
Royal does not think so; and it is certain thut the
editor of the Timrs docs nut think so, or he would
not have published Mr. Hind's letter.
liest, however, 1 should be thought prolix, I
will for the present conclude.
I am. Sir, &c,
A STUDENT OF NATURE.
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