The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1856-1888, 1874-06-20

Of comparison for this purpose. But, a. Greenwich
time cannot be carried accurately all over the world,
il Is inferred at distant places from the local time
combined with the supposed longitude. Alexandra
i the only one Of our Transit stations the longitude
of which can rs yet be determined by teleErapLic
signals. At the rest II viii be necessary 70 tci at
so!ute longitude by observations cf the moon. This
Is a task requiring time and trouble, since, 10 get a
sufficiently accurate determination, about 80 Oh
seryations, extending over some months, viii be
needed. In order that these longitude observations
may be multiplied as quickly as possible (aud for
the determination also Of l~atItude), each parry VIII
take out o large altazimuth instrument, or vertical
circle, with which azimuths or zenith distances Of
the moon may be observed IN any part Of the hea-
Tens. These fue Instruments, as well as the Tran
SIT instruments, have been made expressly for the
expeditions by Messrs. Troughton and Simms. Such
are the modern refnenents Of observation and the
ory that it IS hoped that, By a combination Of alta
zimuth and transit observations, Greenwich time will
ultimately be known at each observatory to within
about a single second, though, a. astronomers well
know, 20 obtain 60 accurate q result as this is a mat
ter Of very great difficulty. The determination Of
latitude will be much simpler, for, in this case, the
error, after q week or two's work, is not likely to
exceed q few feet
Nor will they be by any means alone in their in
teresting task. America and some Of the chief
States Of Europe are making costly and elaborate
preparations 10 Cooperate. France viii, IL Is IN
derstOod, despatch Observing parties TO 81. Paul Isl
and, Amsterdam Island, Campbell Island, and Mar
quesas Islands, in the southern hemisphere, and TO
Pekin aud Yokohama, in the northern, and will also
provide some secondary stations in one or two Of her
Colonies Germany proposes 10 occupy Auckland
Island, Macdonald Island, Bluff harbOr New Tea
land), and Mauritius in the south, and in the north
q station in China or Japan, and a Photographic sta
ton IN Persia, on the line Of the Indian telegraph.
OF American plans little certain Is yet known, but
they will probably comprise the establishment Of
three or four statiOns-One Of them at Macdonald
lsland-in the southern hemisphere, and as many in
the northern. And Russia, strong in the advantage
Of having an immense adjacent tract Of her own ter
ritOry favorable for observations Of the Transit, will
equip, though on a more moderate scale than the
other countries, no fewer than p stations between
Odessa and Japan, Is of which, distributed over
Black and Caspian Seas, are we'll suited for Delislean
observations Of the retarded egress, while the rest
are Halleyan stations, situated chiefly in Eastern ST.
IBERIA and Tartary. At the stations we have above
enumerated, eye-observations of contact, photo
graphy applied in two or three different ways, and
the direct method Of measuring with n hello
meter the distances between the centres of Venus
and the sun will be yariOusly employed. Lastly,
British India will be represented by a Photographic
station in the Punjab, under the charge of Lieute-
nant-ColOnel Tenant, RE; Lord Lindsay, with the
liberality in scientific matters for which he is distin-
guished, will take an admirably equipped private
expedition to Mauritius; and our Colonies and Colo
NAL Observatories are preparing to cooperate at
suitable points. Altogether, there will be at least
20 or 80 stations, scattered over the illuminated side
of the earth, from which, between the hours of about
~half-past l and half-past 6, Greenwich time, on the
morning Of the 9th of December a small army of
astronomers will be anxiously scanning, measuring,
and photographing the movements over the SUMS
face of the little black spot which is to afford US q
solution of one of the sublimest problems of the
universe.