Iron County register. [volume] (Ironton, Iron County, Mo.) 1867-1965, 1885-01-22

instruments of therefracting form. and
larger than any others ever
mounted, are now in process
of construction. A twenty-nine inch is
being made for the observatory of
Paris, while for the observatories of
Nice and Pulkowa, instruments of
thirty inches are ordered. But by far
the largest refractor ever attempted is
the thirty-six inch now being made by
Alvan Clark for the new observatory at
Mount Hamilton, Z. S. A, where it is be-
lieved the atmosphere will favor the ire
mendous power of such a splendid instru-
ment. The equipment and endowment
OF this new observatory are provided
for by fund of 500, 600, bequeathed
especially for the purpose by the late
Mr.. James Lick, who died in 1873
Half a 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 200.
| 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 resources 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 largo telescope can ap-
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 power and 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-
iector, said: 81 remember that after a
considerable sweep with the forty feet
instrument, the appearance OF Sirius
announced itself at 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.
quently 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
zeal telescope work; and Mr.. 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 letter to me that he
had only had one 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 |
of many branches of flu
ture astronomy. +. De,usng, in
Bristol (Eng.) Mercury and Post.