The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1869-03-29

IHE TRANSIT OF VENUS IN 1874 AND l8S2-At
late meeting OF the Royal Geographical So.
"ety In London. STAFF Commander Davis read
a paper on "Antartic Expeditions and the
Transit of Venus" with regard 10 tho transit
OF Venus, Commander Davis said tho great in
terest attached TO It was owing to the data it
an hueu TOT determining the exact distance
OetWeen the sun and the earth, with regard to
Whlon theIe was an estimated error of a. OOO 900
miles. As this transit took place only once
or twice In century, It was necessary for
astronomical purposes TO make hay while the
sun SHINES. Within comparatively brief
space OF time there would be two transits OF
Nenus-one In 1874 and another In 1882. The
value to be attached to the latter transit was
the chief object Of the paper. There were two
methods by which this transit could be efIectu-
ally ooseIVed:-First, by absolute longitudes
from iour statons-one for acceleration by pa
rallax, aud OF for re ardation for the ingress
and the same for the egress; for as the planet
look about six hours to cross the sup's disc
There were but few places from which both the
ingress and ekress could be observed, having
due consideration for parallauc value. For
this method accurate determinations of Iongi-
tude were necessary-an error of one second of
lime would viIiste the result. The other
method was by observing both ingress and
egress from two stations. one for aoceleratioa
by psralIaX, the other for ret trdation: and the
great advantage OF this method over the other
was that the accurate determination Of Iongi-
tude was not an absolute necessity.
In the transit of Venus in 1882, one such
station was to be found in the North American
colonies. and the other could only be obtained
in high southern latitude. The plod,s operandi
suggested that two vessels with steam-the by.
draulic propeller being suggested as the mode
OF applying the steam power should leave
England about June 1881, having on board the
equipment, In men and instruments, for OBJ
serving the transit by the two methods-Jhat
was for three observRtories On the passage
out, two Of these parties, with their instru.
ments, should be landed on the selected stations
for the first method, and at once commence
moon observations for the determ lnatiun of the
longitude. whilst the vessels proceeded to
Hobarton. from which place they would fl ualIy
start for the South in the latter end of Decem.
ber, and striking out in longitude about
los degrees east, endeavor to make Balleny
Island. and, keeping well TO the westward
take the pack and work through 1t to-
wards South Victoria, and then skirt the coast
along as closely posslble for, although in
the Erebus and Terror they did not see the APP
pearance OF an halbor, IL was just possible u
different season might open one up. Proceed
ing south past POSSE ssion Island, in latitude
1871, and failing to find a ha,bo or suitable
place of landing on that island, to return at
once to Possession Island. and land the party
with huts, instruments. and provisions for two
years, the ships returning north, and after re-
fitting, separate and proceed to the two stations
at which parties had been landed on the pas.
tsge out, and after supplying the wants OF the
observatories, and seeing all in fair training
for observing the transit. leave and repair to
Hobarton to prepare for proceeding again
south. and starting about the same time as the
inlr tI,au bnrt,
on the return the other parties, aud return 30
England.
The author suggested the necessity OF edu.
eating the men who were to take part in this
expedition by Lding them, in the first in
stance. to the Arctic regions. as he confessed
that when he went first to the Antarctic he
she uld have preferred to return pack II he had
had the choice. In conclusion, the author dwelt
on the necessity OF England maintaining her
glory as a pioneer of discovery.