Evening star. [volume] (Washington, D.C.) 1854-1972, 1875-01-02
THE TRANSIT OF VENUS.
Compliments to Americans from
Eng land-What America Has Done

The London Times of December II, in an ar
tele upon the transit Of Venus, says:
To begin with the United States. The efforts
made by the government and the astronomers
OF this country are or very remarkable kind.
The government has granted q sum in aid
greater than that voted by any other country.
The Observers are most OF them not only long
trained observers, but men such az Professors
e. d. Peters, Hall and Watson, whose names
sIe thoroughly well known all over Europe.
Their preliminary inquiries and investigation
have been OF the most searching kind, and the
documents and charts which lie before us as we
write, which have been published by the spe-
ciaily appointed and strong commission, OF
which Professor NeWcOmb is secretary, are of
the highest value, and yesterday we took occa-
sion to refer to the use they have been to US in
the preparation OF these noteJ.
All the American stations are Halleyan-a
statement which IL Is no longer necsss ary for US
TO explain. They are eight in all:
The Americans propose 10 make alarge use of
Photography, aud for this purpose they employ
gu arrangement first used many years ago by
Professor WinlOck for photographs of the sun.
The English photOheliogrsph Is a telescope
pointed to the Sun, and male TO follow its motion
by clockwork, and the image thrown by the
object glsss-a small image, as the focus is
necessarily short under these circumstances
after N agnfying by secondary lens, is received
on photograph plate. Now, the Americans
object 70 this enlargement by the intsrpOlated
lens, and they get the image as large as they
require-some fOa Enthusiastically, by employ
ing an Object-glsss OF long focus-forty feet or
tbereabOuts. ut a telescope or this length
would be very difficult TO mount steadily and
drive by clOckwork; so that, instead of causing
the telescope TO follow the sun, thew contriye a
very perfect plane mirror, placed in front OF
the oh, ect-glass, to follow the sun. In this way
aPerfecty stesdy image is obtained st the foc1s
OF the forty foot telescope, placed in horizontal
POSITION, and the Americans claim, we think
Win reason, that this method possesses several
dyantages.
Photographs made by these Instruments will
pc taken, weather permitting, az all the stations
during the whole OF transit, and we already
know that more or less complete series have
been taken al WiadlVostOck, Nagasaki, aud
Hobart Town. or course these photographs
like all the others taken by different methods
by the parties OF the other nations, will be null
tiPhed, as far as possible, at the time of the
two interior contacts, but as the Americans do
not employ Janssen's revolver, they supple
ment the contact photographs and eye obserya-
tons by careful micrometer measurements or
the separation Of the cusps OF Venus when en-
tering on and leaving the sun. II the reader
Will slide three-penny piece over the edge of
penny, be will see the importance OF these
observations. The two points al which the
edge OF the three penny piece, and the penny
appear In contact are the cusps, and il Is easy
10 zee how the distance between them will first
Increase and then decrease as the planet passes
from external TO internal contact. These are
among the observations telegraphed from the
American party at Nsgasaki.
These observations will be N ade by equatorily
mounted telescopes, made by Alyan Clark,
whose nsmeis sufficient guarantee for their
excellence. In addition to these there will be
at each station the usual accompanimente of
telescopes. e., a transit instrument and a
clock; and we have already been informed how
usefully these instruments have been employed
in determining positions not only astronomicaIly
but by means OF the electric Telegraph
method which the Americans 50 wisely use
wherever they go, and from which We 50 largely
benert; for we believe, to take an example, tina.
the lOngitudsS Of our naval stations in the Ne.
diterranesn, Gibraltar and Malta have been de-
tsrmined for Us by the Americans, and not by
ourselves, aud yet one would have imagined
that such an operation would have had some
interest for US.