New-York tribune., 1873-01-02
WASHINGTON.
THE TRANSIT OF VENUS.

lhe prOgramme OF the astronomers OF this country
VINO have IN hand the observation OF the next transit OF
Venus was read at recent meeting OF the Washington
Philosophical Society by Prof Simon Newcomb OF the
Naval Observatory:
About year ago. had the honor 10 address some re-
MATHS the Society the past and future transits OF
Venus and the modes OF observing them. since thr
the Commission charged with procuring the neces
rAry instruments for the observations OF the transit OF
Dec 1874 has made progress with that WORK ana
has elaborated the rough outlines of plan for opera
sions While everything is necessarily in too incomplete
state 70 form the subject of official report is still
advisable for many reasons that ali that is being done
should Ot as widely known possible. The President
Of the Commission has therefore permiedm me 10 give
brief Of its operations and proposed plans
The st action looking toward the observation of this
pheu by American astronomers was so far as anu
aware that taken the National Academy OF sciences
its the Spring Of 1870. The plan then
adopted was organize a committee which shonid
include. either by appointment or by meitauon, the
heads of those establishments 10 which the Government
would naturally look for guidance in scientific enter
prise Of this character II NAV be permitted to mention
my individual impressions in this case may express
the opinion that this action was taken 10y the Academy
with desire have the management OF the enter
prise in ITS hands but 10 AVOID twotod danger 10
danger grew OF Of the features of our Govern
ment-namely, the absence 3l any qeIartnent ' Ul
organization having the exclusive right 10 take
the lead. 10 assume the position or adYsers
10 the Government IN such matter as
This Ia consequence. although II was high time
that something should he DONE the Government had not
been approached in the matter at an ana the prospect
was that not only might action oe deferred unu ~
would he TOO late 10 make the preparations with the
proper care but that when was taken 1t would ne
taken lAuepen0euIB hS various OoN s ~ i5
mCuts ana scientific ORGANIZATIONS each OF which would
oesJe % superntend the operations, and which would
thus find themselves in state OF rivalry notwithstand,
Ing their mutual good S. such state of things would
have been destructive TO the whole pan because the
ease Was one in which unity Of action absolutely
necessary. Now 10 was hoped that the committee nonl-
which interests otherwise in danger Of conflict
iug g Ioup themselves. aud thus form on organza
In this respect the plan proved entirely successful
In his annual report the superintendent OF the
Naval Observatory alluded 10 the action Of the Acad-
envy. aud asked ioU small appropriation to make such
decide on The mode II making the observations In
making this APPROPRIATION, Congress provided that
to oe composed OF the superintendent and Two OF the
iOoSs0I' ~ " it t % "a tHe Sat,,ai .cadenv of
Sciences and the superintendent OF the Coast survey
Win the organization OF This Commission the immedi-
niC result 80 much be desired attained, and II
only remained the cooperation OF the scientific
men Of The country Correspondence was first opened
with such nr the scientific societies known TO
publish transactions IN order 10 elicit their views as O
The advisabty of making national provision for the OO
seryatiun Of the phenomenon. The were, be-
heve, uniformly favorable, and most OF the societies
H6cI f. i mih be- p4actisabe to DO So Fortified BY so
emphatic expression of opinion. the Superintendent
OF The Observatory addressed the Secretary Of the Navy
recommending that the necessary provision should be
made and stating that the cost Of the instru
lneus Vas estimated at S1OOO ana the cost OF organn
ing the expeditions sending them To- their destination,
snd returning them would probably be $4,000 The up
Preparation ioF siIdulets vas piomPty lnaue Oy Con-
ress Ine members Of the Commission nad IN the mean
time pretty wei made up their minds about general
plan oi opeiauons, Dui before nhV uecding on ~ IL
deemed best 10 ascertain the views Of those whose
cooperation necessary 10 carry 1t out number Of
The representative astronomers of the country whose
works or position gave then the night 70 be consulted n
such matter. therefore addressed, with request
for the tui expression o1 their views respecting the
plan OF the yaOns the organization of the e1ped
hons, and other points which they might think proper 10
be brought O. the attention OF me Commission Had
been predicted that tins request would result in bringing
forth such Of discordant views and suggestions
that IL would De possible to harmonic thcm, the
prediction could not have been considered unreasonable
The views elected harmonized TO "A gratifying extent
with those AT which the Commission had already arrived
ami scarcely suggestion received which IL
possible 60 weld with the Others into consistent whole.
As the instruments decided and tho plan OF opera
tOns intimately connected, both must be described
together After careful consideration OF the numerous
ingenious modes of observing the phenomenon which
had been proposed IL found that the choice hm
hed 10 otwO-phoographing the sun with Venus on its
disk, and observing the contacts OF the limbs OF the
planet with thai OF the Between these two, il
dcomed advisable 10 place the man reliance on photo
graphy. IN fact. our distinguished countryman Mr. L.
NJ. rutherford. has successfully carried out what
may consider now method OF measuring small angles
In the heavens IL consists IN photogaphng the object
To 10 examined and then making the requisite measures
the Photographic plate oy means OF very accurate
mierOmetcT lie has thus arrived at degree Of pre-
ciOu considerably exceeding all attained by the ordi-
nary method OF observation In choosing method OF
producing the photographs, the Commission nave found
themselves forced 20 entirely different from that
bF the authorities OF England, and
Russia and recommended by Mr.. Rutherford himself.
Ia ala these plans the image OF the sun, after being
Iorned m the focus the telescope, is enlarged By lens
or camera so as 10 sct photOgraph ol the necessary
But on considering this plan, IL was found that
tho determination OF the amount Of the enlargement
thds produced was Deset with ditheOlues which the
Commission could see no practicable way of surmount
avoiding TINS difficulty led that either ats
gravity nad been misapprehended that Of
therefore deemed best to avoid IL entirely, by making
telescope long that the image formed In its prn-
Fg.u- Jp1H Thor
another 0!culty presented itself The telescope must
then be at least 20 feet long, probably 40 feet Such
telescope pointed at the would scarcely be manage
able Here device which originated independently in
France and IN this country and which Prof WlDlock,
believe the first into practical operation,
sented itself TO consideration IL consists IN fixing the
long telescope IN horizontal position and throwing the
suns into the object gass by teostat. The ad-
Vantages which this method seemed 70 offer have been
forth IN paper circulated by the Commission,
that they need not now he dwelt upon.
other method OF observation consists In detern-
ing the exact moment at which the planet has entered
upon the disk OF the this moment beng that IN
which the cusps Of limb OF the 10 close to-
sfber behind tie planet AS the latter enters upop the
sun or at which the corresponding thread OF light
breaks the planet goes on Considerable dtrust Of
aus method ia felt by the astronomers of this country
and OF Germany, founded the error and dscordance
of the results deduced from IL III the case OF past
transits Dotn OF Mercury Venus BUT, This dis
trust l. moi shared by the astronomers England and
IL / mistake noJ. shared only limited degree by
Ssemed best to put the method into nearly
fun operation as II the best results were
confidently expected This conclusion has been arrived
AT the more willingly that ell the Photographic stations
can used contact staOns that 1t is hoped by
artificial transts 10 learn something or the
causes the 10 which the methods subject and
nuay IL is proposed 10 supplement 1t by measuring
the distance cusps while the planet entering
the limb and leaving it. From some preliminary
trials IL believed that these measures can be made
with great precision Dy uOuDe image incIoineter the
moment which the images OF the cusps thus formed
meet or separated being capable OF observation with
shout as much precision that OF contact itself.
IL been decided to occupy eight Photographic sta
iions, the northern and four III the southern
hemis phere. The individual sta tons cannot yet be de-
ded on indeed II IL best 10 defer the decision as long
as possible. order to obtain Information respecting
:. hich nav be occupied We may, however, TX upon
Pekng as the central point Of themos favorable region
in the northern hens The four stations mast be
scaifered IN China, Tsrary, and Japan and at such