Wessington Springs herald. (Wessington Springs, Aurora County, Dakota [S.D.]) 1883-1891, 1885-02-13
Ealing. London. Among the larce.,

Ealing. London. Among the larges,
instruments possessed by other coun.
tries we may mention the reflector at
Melbourne OF forty-eight inches diane
ter, and the one at Paris of forty-sevcn
inches. In America there are some
very large and efficient r%efractors made
by the celebrated Alvan Clark. At
Princeton there is a twenty-three inch,
at the Washington Naval Observatory
a t%wenty-siN inch, and there is another
twenty-siN inch in private hands. The
Washington telescope cost go, 900.
Those who have an eye to the future of
astronomy and hope for the rapid de-
velopment of its progress will learn
with satisfaction that no less than four
instruments of therefracting form. and
larger than any others ever
OF construction. Atwenty-nine inch is
being made for the observatory of
Paris, while for the obseryatories OF
Nice and Pulkowa, instruments of
thirty inches are ordered. But by far
the largest refractor ever attempted is
the thirty-siN inch now being made by
Alvan Clark for the new observatory at
Mount Hamilton, U.S.A., where tits be-
lieved the atmosphere will favor the ire
mendous powerofsuch y splendidinstru-
ment. The equipment and endowment
of this new observatory are provided
for by a fund of $1,000 BET ueathed
especially for the purpose by the late
Mr.. James Lick, who died in 1873.
Half Il century ago the largest re-
fracting telescope in existence was, l
believe, that bought in Paris in 1929,
by Sir James South, which had an
aperture of twelve inches. The object
glass of this instrument cost FL, 1000.
Comparing the relative dimensions OF
this form of telescope as constructed
fifty years ago with those of our own
day, it is evident that the %our of
opticians have enormously increased,
for glasses of thirty inches diameter
are not a greater rarity at the present
time than those of twelve inches were
in 1880. Only those who have had OPP
portunities of seeing celestial objects
through a very large telescope can APP
preciate the remarkable brilliancy
with which they are displayed. The
definition or sharpness of image
which is always SO essential is perhaps
not so good as in smaller instruments.
but the extra powerand grasp OF instru-
ments of great dimensions more than
compensate for any deficiencies in this
respect. Sir w. Herschel, in describing
some observations with his great re-
Hector, said: 81 remember that after a
considerable sweep with the forty feet
instrument, the appearance of Sirius
announced itself at a great distance like
the dawn OF morning, and came on by
degrees, increasing in brightness till
this brilliant star at last entered the
field of the telescope with all the splen-
dor of the rising sun, and forced me to
take the eye from that beautiful sight"
In England it is unfortunate that the
climate is not favorable for astronom-
ical' observation. The sky is SO fire.
qrently cloudy and the atmosphere SUBJ
iect to such rapid disturbances that
large telescopes can seldom be en-
ployed to advantage. Mr.. Lassell took
his large reflector to Malta and OBJ
tanned most Of his valuable results there.
1t was Herschel's opinion that only
about one hundred hours in the course
of a year are really available for crit
ical telescope work; and MIR. Newall,
of Gateshead, who is the owner of the
best telescope in England-a twenty
five inch refractor, by Cooke, of York
recently said in a letter to me that he
had only had Il thoroughly good
night since 1870, and he saw then what
he had never been able to see since.
Notwithstanding, however, the unfav-
orable climate, an immense amount of
valuable work has been done in this
country, and we may reasonably look
forward to increased activity, both here
and elsewhere, as large telescopes come
more generally into use, and are rec
ognized as absolutely essential in the
development of many branches OF fu-
ture astronomy.-W. +. Daansng, in
Bristol (Eng.) Mercury and Post.