The sun. [volume] (New York [N.Y.]) 1833-1916, 1896-11-01
T%HEBIGYERKES TELESCOPE
VILE SOON RE READY ron USE AT
THE GENEVA OBSERVAToRH.
The Largest Telescope In the worid-Paris
May Have IA larger One for the worid'a
Fair-The New Observatory ana what
II IL LIke-ProG barnard In Chnrrn.

M hsbTEebt EeLSbcOne IN Nhe WOrlh-Fartn
May Have "a larger One for the Worlds
Fair-The New Observatory and what
h 10 Like-ProE HARVARD In Charge.
CHICAGO, Oct. 3l.-Secretary Goodspeed OF
the Chicago University says that the famous
Yerkes Observatory at Lake Geneva will be
ready for dedication aud occupancy by the 18th
Of next month. The observatory Is famous for
what It is to accomplish. 1t will have the largest
telescope in the w~orld-larGer by more than 10
per cent than the Lick telescope In California.
Word has come from Csmbridgeport Mass.
that tho great lens which Alvan Clark has been
grinding for the telescope is ready for shipment,
and the building 10 ready to receive 1t.
Clark is the maker Of the greatest telescope
lonses in use in the world. He ground the 90
inch glass which is in the telescope in the Naval
Observatory at Washington. He ground the
36-inch glass in the Lick telescopel In California.
His business lie solely the grinding of lenses. He
does not cast them. A Paris factory does this
by . secret process which no American glass
manufacturer has yet been able to penetrate.
Two disks are cast for each lens-one of flint
glass and one of crown glass. The two neutral
ize the colored rays so that only a white light
comes to the eye of tho observer.
Tho disks for the big Yerkes lens were cast In
Paris more than four years ago on an order for
the University of Southern California. They
cost $40. 900 In the rough. They were shipped
to Mr.. Clark and lay in his laboratory awaiting
payment. Tho University of Southern Califor-
mia failed to pay for them. About this time the
University Of Chicago was asking public-spirit-
cd citizens for endowments. and Mr.. Yerkes,
who 10 one of the wealthlest of the street rail-
road capitalists of the West, offered to pay for
an observatory to cost $500, 900. The offer was
accepted and arrangements were made with
Mr.. Clark to grind the big lens In hia laboratory
for the new observatory. The grinding has
take about two and q half years and has coat
about $4,000.
The cost OF lonsos increases In proportion to
their size. The ae-inch lens of the Naval OBJ
servatory cost only $780, 900 altogether.
The process of grinding a lens IL necessarily
slow. for n single error might destroy the S4O,-
600 worth OF raw material in q 4o-inch glass.
The rough disks are ground down with revolving
concave tools. Then the surfaces are smoothed
and polished with rouge. The lens lie tested by
looking through 1t at a star. Handling 1t for
this test Is no small task, for the lens and It's
ring weigh about /. 900 pounds.
At its FIRST trial, the lens invariably shows do
fects. No mechanical process has ever made q
lens perfect II such a thing were possibls,
Prof. Clark would not have the monopoly Of
making great lenses. 1t is Prof. Clark's mission
TO go over the lens with his thumb. rubbing
down with rouge any minute inequality of the
surface and bringing II to It's perfect condition.
Thew call the Yerkes lens = 40-inch glass. It's
exact diameter Is AIS inches; the crown "a
about 80 inches thick at the middle and III
inches thick at the outer edges. The weight Of
the crown glass alone Is 2o5 poun DIS and OF the
! flint glass $40 pounds. Prof. Clark does not
call the Yerkos glass his limit. He thinks he
can grind n perfect lens AS inches In diameter.
The dihiculty in the way of making a larger
lens Is the weight and hexibility OF the glass. A
glass larger than as inches in diameter and
measuring only about ) inches at the thickest
There are those who believe that the 45.lnc6
glass 10 impracticabie.
very expensive and hazardous matter. When
the Naval Observatory at Washington moved
into Its new quarter. four years ago. the moving
ton 10 the process. HALF u dozen of the pro-
fessors took the glass from the telescope with
between mattresses. and packed tLem in a box
which was put on u springy foundation In q
that could be found was h'tched to the wagon.
and the procession moved ut o anail's pace over
senderl! than th.. pair q disks weighing
ike this goes ON a railroad Journey. It
IL tw u II sar,.d Il hair i is . s1, Witch Or old - mo Inner, \
S sa. sS.'n fSe A Journey 1ssea Of Il. 'p 9srkes lem len. a iro@
with interest by the whole scientific world. Tho
lens will not change cars on the journey and the
ses.sssa' At the the d dts;"s g s masss Of ri f,s sr joaeae y
will be warned to handle their charge as gin
gsrly as possible.
When tho car reaches the end Of its Journey.
at the little town of Williams Bay. it will have q
mile still to 60. and this mile will he the slowest
II Will travel. The roads are good and there 10
little danger Of any accident.
The Yerkes Observatory stands on the north
miles from Chicago. The Chicago and North
western Railroad extends through the village
OF the ohAer vetory grounds. From the village
Of Geneva to the observatory by water is about
for the rich people Of Chicago. The vllIsso is
unlmportsnt II IL merely u stopping place for
very beautiful summer homes. n. X. Fair.
banks. the millionaire, lard man, owns one Of
them the Goods /; q oL Lsi.1 s,o %ho made asor his %llllons II,
palaee-car fame, George j. Walker. Z. i. Aver,
Mrs: sturgi.; and many other very rich people
The sito was chosen because OF its freedom from
any adverse influences. such al. smoke. The site
OF the observatory consists OF about fifty acres
OF wooded land fronting on the lake.
The construction OF the main building of the
that Of a Roman cross with three dolaes and a
meridian room At the e%ItremIties. The prlnci-
and west, with the dome for the big telescope at
the western end. Thsdome IL 90 feet In diameter.
tsioscops, Whieh T. about IS 81 feet long. II Tbe s iron
work OF the dome 10 ITO feet high. and 1t weighs
o. o1' BALL E .So. sGns: w " . ~Sso' sSa on 'he swsh'i Il 4 ' al.
1usted so desicately that Il could be turned by
hand, IL ID To be operated BY electricity. The
marble floor of the observing room Is rs feet In
diameter. It can DO raised or lowered 2! feet
by means of electric motors. Electric motors
have never been used before for the manipula-
ton of telescopes.
Tho equatorial mounting for the TELESCOPES was
made BY. Warner q Swasey and was exhibited
At the World's FAR. 1t Is similar 10 the mount
Ing OF the Lick telescope but heavier,
The attachments OF the telescope will include
a position micrometsr; a solar spectrograph for
micrometrical and Photographic Investigations
Of the spsctra ot solar phenomenal. n speotro-
| hNllOKrRDh Tor DhOtORraphlnR the solar ClrOmu-
sphere, prominencos. and faculte, by mono
chr0matic light; q stellar spectrograph for re-
searches on the spectra and motions of stars,
nebul~. comets. and planets. and q photoheiio-
graph of great focal length. for phOtographing
the direct solar image on a large scale.
There are two smaller domes, the one to the
northeast containing q lY-inch telescope and
the other a .24:inch reflector, Between these
aomes 10 = h~ellostat room 100 feet long by IL
feet wide. A heliostat with q 24-inch plans
mirror will stand on a pier at the north end OF
the room under an iron roof which can be rolled
10 at the extreme eastern end OF the obselva-
veninR air space. 1t 10 designed to contain a