The Republican journal., 1874-06-25
NUMBER 81.
The Transit of Venus,

| AIolll C,tIll OUItl D4 IL ptllOt VI LIZ C.tl D
Until very recently the transit has been
considered the best means Of getting the
suns distance from the earth and, perhaps,
the only means. Until within the last ten
years the result obtained by Eucke, from
observations made at the last transit, has
been accepted as the true distance between
the earth and the sun. This result was
96,OO0,O 900 of miles. Latterly, however,
other methods Of observation have been
discovered and employed, and they all
tend to show that this distance is too
great by three and a halt to four millions
OF miles, and that the true distance is
about 81 900, 900 of miles. This latter re-
suit was liable to large uncertainty, and
it is hoped that the observations on the
| coming transit will give result whose
| probable error will not be more than 800
600 miles. In view of these and many
other facts the Importance Of the coming
transit IS evident, and all nations OF the
civilized world have taken measures to
observe it. BY good fortune none are
more thoroughly prepared for the work
than the Government of the United States
About three years ago Rear Admiral
Sands, at that time Superintendent of the
| Naval Observatory, look the nitiatorv
| oeSP' " 'iiIS tllC jll1lttl W lllc dtItutlOu
OF Congress The sum of $50, 900 has
been appropriated by Congress for making
the necessary preparations, under the di-
rectIon OF competent board of scientific
men. After full consideration of the sub
Ject this board decided that the United
States should send out at least eight
| parties to observe the transit, each party
TO he equipped with the means of making
both eye and Photographic observations.
AS these parties would 90 to countries
rarely visited by scientific observers, it
was also deemed desirable that they should
be provided with the means of making as
many physical observations as possible.
Among the incidental advantages which
lt,presented was that of fixing accurately
| the latitudeS and lOngituleS Of many I'M
portant points in the western hemisphere,
practical service to navigation of the
greatest possible consequence Besides,
the geographical position of many of the
most important cities in the Indian Ocean
are at present but very inaccuratelv deter
mined, Thus provided for, the commits
| sion proceeded TO make detailed plans for
the organization OF the parties. They
| decided that all the stations and all the
| parties should be fitted ont in exactly the
same manner, and consequently adescrip-
ton OF one is a description of all Each
| party is TO consist Of five persons; an
astronomer, commanding; an assistant
astronomer. second in command a princ-
| pal photographer. and two assistant pho
tographerS.
The Instruments with which they are to
be furnished are rs follows; A telescope.
| having an Objects glass OF five inches
aperture and seventy inches focus eqlla-
torally mounted, provided with a driving
clock, the whole SO arranged as TO be ad-
iustibe to any latitude in either the north
ern or southern hemisphere; 4 portable
meridian instrument, (tor determining
both time ard latitude, having an object
glass two and half inches aperture and
thirty inches focus an astronomical clock
and Il chronograph There Is also included
Il complete set of Photographic apparatus
that is, a telescope, five inches aperture
and forty feet IN length, lying horizonta ly
in the north and south direction, the image
of the sun being reflected into il by means
OF mirror. Besides. there are a number
Of s}n9ll,, inStGument !, such rs, levels 9
general camp equipa@e of every variety
For convenient use in the field, three port
| tlDIt' btlStIN w ~ iIt Ntlt W llH tttl
party. One is for the equatorial telescope
one for the meridian instrument, and thu
II third fer the Photographic apparatus
These houses have all been constructed il
Washington and erected on the ground
of the Naval Observatory, forming curl
ous and interesting village The photo
gripherS have been educated to this worl
by photographing an artificial transi
arranged tor the purpose
The transit happens on the Sth day D
: December Ii will last about four and
half hours. OF course it will be yisibl
from all places where the sun is above tn
horizon during that time At the begin
ming of the transit the sun is Just settn
at a point few hundred miles west o
our Pacific coast At the end Of the tral
sit it has Just risen in British India an
Russian Siberia. Consequently the mos
: favorable places for observing the trans
; are on the opposite side of the earth fror
the United States. In selecting station
the commissioners have found the weathe
SO much more tavoable in the norther
than iE the southern hemisphere that the
+ have decided to make three stations in tn
! former and five in the latter, in order t
: equallze the chances Of getting obSerya
q tions of both hemispheres. An observe
I in the northern hemisphere will see tn
o planel cross the suns face somewhat neal
O er the centre than an observer III tn
/ southern hemisphere. Each party wi
take about one photograph per minute,
the weather is clear BY combining al
! the photographs taken at one place it wi
, ! be possible TO trace the exact path {
! Venus over the suns disc, as seen fror
/ that place. Then by comparing the trac
y pursued by Venus as seen from souther
stations, all data necessary for dctermll
: ing the suns distance will be obtained
; Though preliminary reports OF the Amer
a can observations will be made. the con
pete work will not be published unde
/, Two years.
o The Swatara, which will take all tn
i Southern parties to their stations. wi
5 probably sail directly for the Cape {
e Good Hope, to compare chronometers {
@ the Royal Observatory situated Their. A
D the same place store of provision. wi
be laid in, and, above all things, a larg
number OF hens will be taken on board
and upon their good conduct the succes
OF two OF three of the parties will great,
! depend. For at Crozet. and kerguelc
, now known, for procuring eggs to albuniz
the Photographic plates than through thu
+ good offices of the Cape Of Good Hop
hens. Both the Kergnelen and Croze
Islands are nninhabted. The parties LET
on them have to stay till the vessel returns
Provisions will be left for them sutficen
for year, in order to insure against any
possible accident. From kerguelen tht
vessel goes to Hobart Town, in Tasmania
(or Van Diemen's Land of the old geogra
plies where a party will be landed ant
another viii be left at Bluff Harbor. il
New Zealand; and then the Swatara pro
ceeds to Chatham Island. This island is
either uninhabited, or else inhabited by
cannibals; it is not definitely known
which is the fact The vessel will remain
at this station till after the transit and
then take up the other parties
The parties for the northern stations