Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1892-10-06
Snme LArge TcI.scnnr.,
To ne Elior Of ne Dispa.c1:

Some large Telescopes.
To ne EIror Of ne DispG'ct:
The GoJl-J ,mocr1f, OF st. Louis. quotes
from the London Su81ri the following
Tho largest rejecting telescope in the
world-tLat of Nr Commons about !
feet 10 inches in diameter"
10 is very strange that a leading English
journal should layo made such a mistake.
wonder ! d would have made It If Eng
land Lnd VIVA. the Emerald Islo really
possesses for the largest rejecting tele-
SCOPE ia The world lo hat of Earl Rose, at
Tarsous'own. ireland. it, par1boic re-
hcctor is ST. taf IN diameter, aud IL is
The fruit of chat one uOblcmau's Hbe-
rlilty end enterprise. lie spent upon his
huge instrument about $ 5000 More
over, the gigantic scheme Of blr. Deloucic.
which On" N11d4ri SETS forth, may be
I without government ald, though II IS for
National g.Drl 1c4tiOn. That scheme rs 20
have fer the international exhibition 10 be
held IN Paris, IN the year 1900, q grand re-
Hcctor with diameter of q feet 40 inches
and tube ot A yards! The difficulties in
the way of accomplishing such work are
very great, but mGy not be lnsurmounta-
bic. Airead. some preliminary pro-
/ gross has been made by the great
Observation-Disclosures. the brothers Henry,
+ Paul Gaurer and Mr.. Dcloucle. The cost
P OF the instrument aud allIt- appurtenances
is estimated at SjJ0,uua. It's proposed d.
mansions may zoe greatly reduced and II
would still be the largest reflector III the
world, and every such reduction Will
LARGELY increase the prlctlcQbillty of ITS
construction. II is hoped that the grand
scheme will not he abandoned. although
IL should rave 90 be largely modified SO IS
10 make 1t feasible.
Mr.. C0mmous's telescope is said 20 be
feet 10 inches III diameter. lie Nerrier had
one constructed Tor the observatory at
Paris very nearly as large feet inches,
think, with reflector, not of solid CO.
hercut material, but with metallic foil. in
side of glass. But the weight Of this
mirror caused II to warp, which marred
the accuracy of tho instrument. Indeed,
the necessary weight of the reflector IN all
4 large instruments IS q great drawbacks N
using them 10 advantage. And the same
difficulty attaches 80 the object. glasses OF
large refractOrs. 1t J. reported that the
great Lick telescope cannot be used 10 an
advantage commensurate with It's size IN
horizontal position OF positions Gp-
preaching tho horizontal. because Of DIS
tortIous caused by the weight of its
immense solid lens Of 3 feet diameter.
The largest rejecting telescope IN the
world, then. Is that of Lord Rose, who
had il constructed under his own super
vision and paid for 1t out of his own
pocket MCssrs. DelOucle, Gautcr, ana
Henry, and their cO-Opcrators are pro-
posing 20 have this surpassed by one OF
9 feet 10 inches IN diameter. J Is material
IS not stated. Lord Bosse : G-foet reflector
is composed of sOnd alleged metal very
highly polished.
The largest refractng telescope in the
world is that Of the Lick Observatory, in
California, with an object-glass Sj
inches in diameter II, too, Is the
fruit Of individual munihcence. The
next largest of the same class IS that OF
the Russian GOvernment-3l inches Ia
diameter The next two are Of the same
slzc-26 inches in diameter. One Of them
belongs 10 our own government, and IS at
the National Observatory az Washington
/ The other was made for Washington and
Lee University, but boy the hberality Of
Mr.. INcurgus Mccormack was secured for
the University of Virginia. All four Of
these splendid instruments were con-
structed in our own country by the cele-
brated opticians. Alvin, Clark Il Son, one
of whom in testing fine telescope, made
the important discovery that Sirius Is a
double star.
As il Is now proposed TO surpass the
Grand rehectors OF Mr. Commons and
/ Lord Rose, so even moro definite efforts
are making TO exceed the unequalled Lick
refractor IL is reported that both South
I {
terestlng Clark X Son IN the WORK OF
making for each Of them telescope whose
objcct-lens shall have a diameter of ut
least 40 inches. May 1t be done.
Professor Hall, OF our National Observa-
tory. highly distinguished himself and LIS
/ instrument by the discovery OF the two
tiny moons Of Mars. which are named
Demos and Phobos, after the chariot
steeds of this God Of War And Professor
Barnards has recently had the coveted hon
or OF discovering q fifth satellite OF the
giant planet Jupiter with the Lick teIe-
have long had the notion, sometimes
/ bordering on belief, that Venus has
/ moon. Maybe one Of these great Poly,
phemian eyes Of modern astronomy VIII
I yet unyell It.
Tho interest in astronomy which you ey-
hlbit by the contents of your columnsirom
time 10 time. is most commendable and
has encouraged me to pen the foregoing
lines. Our own country and counirymen
are bearing "a NOBLE part IN advancing the
useful and fascinating science OF astroho-
my aud a recent evidence or TINS deserves
/ 10 be noted.
| Mass. has established a statlonat Arequlpa.
Peru. at an altitude OF 5000 feet. where
everything is favorable for the use OF farce
telescope. Professor Pickering, who has
already achieved so much 20 his honor,
/ with his instruments at Cambridge, makes
an earnest appeal for S20J,OVJ with
which TO equip this new station with lh-
strumenis suited to its admirable Location
and TO the fair competition wnlcu ne de-
sires TO run with his most-tayored co;
laborers. Here private, If not individual
munGcence may again happily interpose.
one person may not be able or wiling 10
undertake the whole of the desired WORK.
but as the stars are not only binary OUT
multiple, so there NAV be combination OF
hearts and hands on the EARN 70 set lor-
/ ward this glorious cause OF exploring INC
skies. What telescopes has kchmohu
Refracting and rejecting telescopes cah
be compared inter seSc by their dlmeIsloHs
but II will not do 10 compare rehectors
with refractors by the size OF their mirrors
/ and obiect-glasses. Rehectors require ohly
I one mirror; refractOrs require Two lenses
of different kinds OF glass with ditereht
+ powers OF refraetion, so as 10 rehuer tno
instrument as nearly achromauc Us post
bic. Each of these lenses has 10 DC pre-
nared with exceeding accuracy ana tDen
I adj listed 10 each other with the greatest
precIsion. The difficulty OF getting large
masses OF homogeneous, hawFess giasss 10
RIcHIoSp. September 80, 1882.
opeen Christina and King Alfonso, Of spain'
.rTtivag ~ Naorid Monday from san SeoaslAn,