The Cincinnati daily star. [volume] ([Cincinnati, Ohio]) 1875-1880, 1877-07-27
THE GREAT LICK TELESCOPE.

Richard S. Floyd, one of the Trustees
OF the Lick Trust, has just returned
from an extended European tour. Dur
ing his absence he has talked with many
scientific men OF this and other cnun.
tries, but almost invariably found them
afraid to commit themselves 10 an opin-
ion as to whether a greater success Can
be obtained with II fl citing or reIract-
ing telescope. Prof. Newcombe, of the
Observatory in Washington, alter his
visit TO Europe to look into this matter
for Mr.. Lick, reported Warmly in favor
of a gigantic lelractor, and forwarded
complete estimates as to the cost.
He has since changed his opinion,
however, and now recommends silver.
on-glass reflector Of about seven feet
diameter. Ross's. HerscnePs and other
celebrated telescopes nave speculum.
metal reflecJors, which have until late y
been considered the best. Now the palm
is claimed for an inVentlon of Leon Fou.
cauits by winch silver in solution is de-
posted on glass. Foucault made re-
Hector upon this system about thirty.
une and One-tlth inches in diameter
land excellent work has been accom-.
lished with it. Alter his death a re-
tector upon this plan about four feet in
diameter was constructed for the ubser.
va, Ory.
Owing to some not thoroughly ex-
plalneu cause this has not proved sue
cess, and another Of the same dimeu-
slons is being constructed to replace it.
Great interest is manifested in the re
suit OF this second experiment, Whicu
can not be proven for year yet. DR..
Higg MS, the Weli-kn0Wn astronomer,
also iayors large reflector, as it is bet
Ia,
ite study. IL is naturai that he should
prele, ID reflector, as he desires to nave
the field oil physical astronomy charged. =.
Theoretically reflector Of Iour leeL
in diameter ls about equal to Il relractor
of t. euty-siX inches. rhe Ross reflect
or is six leeL III diameter, oAly foug feet
OF which are effective, and So Tar t. has
been proven that more than four feet OF
the reflector can be made effective. The
great trouble with tue roh e or IS that IL
il very sensitive TO atmospheric cuanges,
while with the relraCtOr the difficulty
lies in the secondary spectrum. TIe Oh
ject-g ass Of the re .factoris composed oil
Two glasses joined, The QUEER being OF
crown glass, The inner OF flint. Rays
passing through the crown g.ass are re-
fracted, ana entering the fi.nt glass al e
relrac ed. The consequence is tnat per-
lect achromatisM is lmpos S.Dle, and the
d ticulLy Of compensatlng these Iefrac-
tlous increases with the size OIL the OBJ
ject glass. The largest retractor in tue
" orlu is tuat the Washington Observ-
ato,y; it is tMenty-slx inches in diane
ter, and is an excellent instrument.
Mr. FLOYD SAID that after as, careful
an examination as ne could make, he is
inclined TO believe tnat the best inter-
ests OF the fund will be served, to have
constructed a larger refractor than any
yet made. This ought not to cost, COM
plete, more tnau $3.50, 900. Then there
win be subsidiary reflector, about lour
leet in diameter, supplied with both
sllver.on-sl slass and speculum metal MR.
rors. Such all instrument has been Of
fered, or rather parties have agreed to
construct one, Tor about $40, 1000. Iell, of
Paris. will undertake Lo make crown
and flint glass discs for the object glass
of a lorty-luch rciracLOr for SO 0O0-stip-
ulating that he snail be allowed two
years lor their construction. Alter they
nave lett his hands the optlclan will re-
quire about three years more 10 figure
tuese discs mathematically. San Fran
CISCO Bulletin.