The Manitowoc tribune. [volume] (Manitowoc, Wis.) 1866-1878, 1874-12-24
THE TRANSIT or VENUS.

inst, the transit Of the planet Venus
across the suns disk began. For over
one hundred years this event has been
looked forward to with intense interest
by the scientific world and elaborate
preparations have been made by various
nations that every possible observation
be made The last transit of Venus
occurred in 1869, the next one will take
place in 1882 and then there will not be
another until June 3, 2004 The transit
Of Venus obtains its Importance IN the
scientific world because it affords the
means of determining the exact distance
of the earth from the sun. Astronomers
have found after laborious calculation
that the distance between the centre OF
the sun and the centre of the earth is
between 80, 200,O00 and 90, 700, 900, and
it is hoped that the observations made
on Tuesday viii enable the distance to
be determined exactly. So much solici-
tude in regard to SO small an error I'D
curious to many. It is necessary to be
precise for the use of the nautical al
manac makers practical astron-
omers and mathematical compaters,
who have to calculate the movements
and positions Of the heavenly bodies for
several years in advance, for the use OF
80 he h lot =
ter in making their perilous voyages
through the painless waste Of waters,
have no sure guides but their chrome
meters and the movements and positions
of the sun, moon and stars. It is, there
fore, in the highest degree essential to
their safety that the chances for error IN
the nautical almanaces shall be reduced
to the lowest possible minimum. 1t is
for this reason that there is SO much
solicitude concerning the precise dis
lance of the earth from the sun and the
moon and the other heavenly bodies
within our planetary system. The
whale ship which starts for three years
cruise among the waters of the Arctic
ocean depends iritfrely upon its nauti-
cal almanac for finding its position.
The calculations Of the astronomer tell
where the navigator should find certain
stars, and if there is even SO small an
error as half million miles at the start
ing point of the astronomers calcula-
tons, it may make most important
difference in problem which runs over
years, and the navigator would find
himself wrecked in a canal where his
calculations said he was in the mid
ocean.
The astronomers sent out by the
United States government were stationed
on various desolate islands in the South
ern ocean where it would be daylight,
and they were seven thousand miles
apart SO as to get the longest possible
base line. Yet seven thousand miles is
not much of base when you are trying
to measure the distance of an object
80, 100000 of miles away and when the
angle to be marked by the telescope
and by the observer is less than the one
tenth part of a second, or less than one
part of scale divided into twelve mil
lions, nine hundred and sixty thousand
parts. The diameter of the Garth is
just next to nothing when dealing with
such vast distances and the infintesimal
angles they present. Minute, however,
as these subdivisions of space may be,
and great precision as they demand in
the instrument and in the observer, still
more minuteness is required in marking
the exact instant of time when the criti-
cal point of an important astronomical
observation is made. The experienced
observer whose trained eye is guiding
his skilled hand, Will at the critical
instant touch the key of delicate piece
of machinery that will mark the hun
dreth part of second of time-the hun
dreth part of the interval between two
ticks of a watch-and which instrument
could mark the thousandth part of
second if human eye and hand were
quick enough in their action.