Evening star. [volume] (Washington, D.C.) 1854-1972, 1890-09-27
THE GREAT FoRrY-INCH LENS
A Look at the Recently Arrived Glass
That Will Take Us Deeper Into Heaven.

A Look at the Recently Arrived Glass
That Will Take Us Deeper Into Heaven.
From the Boston HsrslL
In quiet little room nj Cambridgcport ycs-
terday shown for the firs. time the pre-
cious glass which is 10 be used in making q
telescope that shall eclipse even the famous
one now mounted at the Lick Observatory in
California The gathering took place in = cell
lar OF the residence OF Alvsa q. Clark. the
famous telescope maker. and there were
present Judge Il. NJ widney. president OF the
University Bank OF Los Angeles. Cal, and Q
trustee OF the University Of Southern Cali
fornia; Mr. Alvan @. Clark; his brother. George
CLARK: Judge widney's son. Robert; three OF
Mr.. Clark's assistants. and . Herald reporter.
When the lid OF the big box removed Mr..
Clark tenderly lifted away the excelsior fiber
Whlch covered the precious lens There 10 Law,
cushloned on its soft bed and rejecting back
the hight from the little oil lamp held at Q
respectful distance by a careful assistant. II
was sight for astronomical eyes 20 behold.
j he glass measures about 10 feet in circum-
ference. or feet inches in diameter Al
though II Is inches thick at the center and
l. inches at the edge. Il was as transparent 40
q bit OF thin plate glass when carefully il was
raised on its edge in the box Mr. Clarke
hands fondied it AS he would a baby while he
mcrmured; What beauty it is, no one ever
saw its like"
George Clark hecked OF the particles Of
dust that chung 20 1t with a soft elk handker-
chief and touched II as lightly AZ a lady michs
her powdered cheek. Mr. widnev's ewes
danced with pleasure he glanced through
its transparent thickness The Herald re-
porter touched it rcvorently before It was laid
carefully back in its case to await its finishing
process. A sigh OF relief escaped the veteran
lens maker wheE he saw Il safely reposinC once
more on its soft cushion and the fiber replaced.
10 W. IN or
this was done, for the lens represents about
twelve months work already. though two or
three years will be required to finish it. When
II Is ready Tor Its position IN the big telescope
II VIII represent value OF from 100000 to
$4,000. Ii is now insured for large sums by
two OF the biggest insurance companies IN
Boston.
Judge Widney expressed thorough satsfac-
ton with the appearance OF the glass. and said
lie had not tho least doubt but that it would be
not only the very largest. but the most perfect
one ever attempted Ii Is nearly five inches
wider IN diameter than the Lick telescope glass
Before ITS Partisan manufacturers succeeded in
turning out this perfect specimen they had
melted out dozens and dozens Of others like in
IN size, but possessing no claims OF rivalry as
regarded perfection. Even this one had 70 be
cut and rScut before all the air bubbles and
inequalities were carved out Of IL. This reduced
its thickness by couple of inches and the
further processes II will have 10 undergo before
II is tit Tor Its cell may reduce its present thick
ness very materially.
sir. Clark says that its curve on one side 10
almost perfect. but that the other will stand a
great deal of cutting down. He has not vet
decided whether he will have the work done at
his mandatory in Cambridgeport or put up a
new plant to complete il near the scene of its
future home an California. When the Lack
glass was ready, 1t was sent away in n speclal
parlor car, and the cost OF transportation alone
amounted to $1,000
The first process that this new and 90 far
greatest lens ever attempted will have 70 I'M
dergo will be that OF grinding TO the proper
curve IL will be placed on "a mill and made to
revolve at sloS and uniform rate OF speed
The finest OF sharp steel instruments will cut
out the surplus glass, and a smoothing ma
chine moving in constantly changing curve,
will be for months and months passing over its
surface before the lens can be utilized. During
this time il will be tested. perhaps hundreds OF
times, by the aid of a silver mirror till its
proper focal power shall been established
Each of the processes employed in the opera
tion is intricate and delicate. That of getting
the correct focal power may, however, be con-
sidered the most interesting. On being set
before the mirror a little star-like raw Of light
will be made to pass through the lens aud re-
Elected back through it again from the mirror.
Until ali the inequalities OF density in the
glass are removed the ray of light transmitted
will not be perfect in shape Back and forth
the lens will have to go from the grinding and
smoothing machine to the testing apparatus,
uhti llle tiny ray % llpnt IL as perfect as when
il first leaves the little lamp that sends il forth
The grinding machine is a most ingenious
affair. 1t is worked by two cranks, one Of
which revolves seventeen times 10 the one time
that Its fellow moves around. This makes the
lens present constantly changing surface TO
that which is polishing it. Red oxide of iron
is used for the grinding and beeswax brings
out the perfect polish. Even after the ma
chimes have done all their fine work it will re-
main for human fingers 20 complete the poll
ishing process. The focal length OF the tele-
scope cannot be decided upon until the focal
power of the lens has been established, but 10
is estimated that il will be between IS and 60
feet Besides being an object glass il is also .
photograph glass. The largest astronomical
photograph lens previously made has boon but
"A inches in diameter, and it il expected that
the present one will accomplish unheard-of
triumphs in revealing wonders Of the starry
armament
Judge widney said that through il the moon
will look as if only 100 miles away. and that il
there are any cities or large buildings on its
surface their presence will lie revealed through
Its aid. The glass, II is thought. will also settle
the question as TO the supposed signals OF light
which the inhabitants OF Mars understood
TO be making to the people Of the earth.
The observatory for which this new tele-
scope is intended is TO be about u or Is miles
from Los Angeles, on a part of the Sierra
Madre mountains known as Wilson Peak IL is
claimed TO be better site for observation than
the Lick observatory. Ii is about 60O0 feet
above the sea level and is free from the mist
and foSs which roll in through the Golden
Gate and spoil many chances Of observation
with the Lick telescope. The atmospheric
conditions altogether are said 20 be moro
favorable for astronomical search than Of the
former place.