Year: 1874




him to keep on plotting for the nomination


The Observations Of the Approaching
Transit.


The extensive preparations for observing
the great transit are well nigh matured, and
the last expedition to that end has recently left
England The scientific campaign has been
planned with more care than any military
movement for the conquest Of territory. and
astronomers are looking with intense interest
for the result Unless the whole habiable
part Of the globe is simultaneously shrouded
in mist and cloud ON the day of contact there
is no question that the momentous occasion
will be successfully improved by two or three
of the observing parties. One Of the latest
additions to the astronomical apparatus is in
troduced by the English Astronomer Royal.
by which photographs of the external and in
ternl contact Of Venus with the SUMS disk
will be made every second during the critical
time. e. .I


The pubic mind has usually been moro in
terested In the practical than in the theoretical
hbors of the astronomer But this grand
international investigation of q rare periodic
phenomenon is intensely practical when under
stood.


For nearly whole century previous to
1862 the suns mean distance was confidently
regarded as ninety-fve million five hundred
thousand miles, and as late as 1866 the As
tronomer Royal Of England said there was no
probability of an error Of half million of
miles in these figures. The old calculation
was shortly aftsrward invalidated by further
astronomical computations and by o revision
of the laws of light until the distance was
reduced theoretically to ninety-one and halt
millions. To determine this distance ac-
curately is Of great importance for all calcu-
lations in which the suns attraction within
the planetary system is influential, and in all
work for the nautical almanacs, by which the
mariner is guided The imperfection Of the
tors is necessitated by the facts that the lunar
motions are rendered irregular by the dis
turbing attraction Of the sun, and the
amount of this disturbance cannot be oom-
puted until the suns distance is accurately
known. As the lunar tables afford the means
of calculating the longitude Of o ship at sea,
and are depended upon for this purpose, in
the present state Of knowledge all longitude
determinations are exposed to error.


The benefit to navigation from q successful
observation Of the transit Of Venus would
alone repay the labor and expenditure neces
sary for the present astronomic campaign.
Only two such opportunities for observing
Venus passage across the suns face occur in
the long period Of hundred and twenty-five
years, and these two occur at an interval of
eight years. The last pair of transits took
place in 1851 and 1869; and had the present
opportunity been lost it would not have re-
turned until June, 2OO4-a very long time for
the world to wait the solution Of q problem in
which so many scientific and practical issues
are embodied. The astronomers Of the present
worldwide popular interest with which their
schemes have been received and their arduous
undertakings so abundantly provided for.
The lavish equipment with which they have
gone forth to their antipodal stations proves
that where the legitimate work of science-ob-
servnion, not speculation-is at stake, govern
ments and individuals are ready to advance
millions of money if need be. This fact
should encourage scientists everywhere to
pursue the patient path of actual research
into the wonderful phenomena of nature, and
lure them from the delusive by-roads which





takers Of science prefer and pursue for fames
sake.


Although some considerable time, perhaps
o year. must elapse before the final and ma
tured results Of the forthcoming observations
can be published, we shall no doubt learn at
an early day what if any, material discovery
has been made.