The Portland daily press., 1890-10-01
APREcIoUs DISK OF GLASS.
Avian CIark's Latest and Most Per-
feet Work.

10 CHOSEN lew, in quiet little room at
Cambridgeport, was shown for the first time
the precious glass which is to be used in
making a telescope that shall eclipse even
the famous one now mounted at the Lick OBJ
servatory in California. The gathering took
palce In cellar of the residence Of Alvan G.
Clark, the famous telescope maker, and there
were present Judge r. M. Widney, president
of the University Bank of Los Angeles. CAL,
ard trustee Of the University of Southern
California; Mr.. Alvan G. Clark, his brother,
George Clark; Judge Widney's son, Robert,
three of Mr.. CIark's assistants and Herald
reporter.
When the lid Of the big box was removed,
Mr.. Clark tenderly lifted away the excelsior
fibre which covered the precious lens. There
it lay cushioned on its soft bed, and reflected
back the light from the little oil lamp held
at a respectful distance by careful assist
ant. 1t was sight for astronomical eyes to
behold.
The glass meaures about 10 feet In circum-
ference, or 3 feet inches In diameter. Al
though 1t is q inches thick at the centre and
as a BIT Of thin plate glass when, carefully.
1t was raised on Its edge In the box.
Mr.. Clark's hands fondled it as he would
baby raised out of its cradle, while he MUIR
INJURED: What beauty 1t is. no one ever
George Clark flecked off the particles of
dust that chung to 1t with soft, silk hand
kerchief, and touched it as lightly as lady
might her powdered cheek. Mr.. Widney's
eyes danced with pleasure. as he glanced
through its transparent thickness.
The Herald reporter touched it reverently
before 1t was laid carefully back in its case
to awaits Its finishing process. A sigh of
relief
ESCAPED THE VETERAN LENS MAKER
when he saw 1t safely reposing once more on
its soft custom and the fibre replaced. He
Was IN state Of more or less anxiety TIL
IL months work already, though two or
three years will be required to finish it.
When it is ready for Its position in the big
telescope. 1t will represent value of from
$4,000 to $4,000. 1t is now insured for
large sums by two of the biggest insurance
companies In Boston.
Judge Widney expressed thorough salts
faction with the appearance of the glass, and
said he had not the least doubt but that 1t
would be Tot only the very largest, but the
most perfect one ever attempted.
1t Is Yearly i've inches wider In diameter
than the Lick telescope glass. Before its
Partisan manufacturers succeeded in turn
ing out this perfect specimen they had melt
ed out dozens and dozens of others like it in
size, but possessing no claim of rivalry as
regarded perfection. Even this one had to
be cut and recut before all the air bubbles
and inequalities were carved out of It, This
reduced its thickness by couple of inches.
dergo before 1t Is fit for its cell may reduce
its present thickness very materially.
When the Lick glass was ready, 1t was
sent away in special car, and the cost of
transportation alone amounted to $4,000.
The first process that this new and so far
greatest lens ever attempted will have to
undergo will be that of grinding to the prop
er curve. 1t will be placed on a mill, and
made to revolve at slow and uniform rate
of speed. The finest Of sharp steel instru-
smoothing machine, moving in constantly
changing curve, will be for months passing
over its surface before the lens can be util-
led During this time It will be tested, per-
haps hundreds of times. by the aid of sill
yer mirror till its proper focal power shall
have been established.
Each Of the processes employed in its
operation Is intricate and delicate. That of
getting the correct focal power may, how
being set before the mirror little
STARLIGHT RAY OF LIGHT
will be made to pass through the lens and re-
Elected back through 1t again from the
mirror. Until all 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, until the tiuy ray Of light
Is as perfect as when 1t first leaves the little
lamp that sends it forth.
The grinding machine is most ingenious
affair. 1t Is worked by two cranks, one of
time that Its fellow moves around. This
makes the lens present constantly chang
ing surface to that which is polishing 1t. Red
oxide Of iron Is used for the grinding, and
hnn hrIvr nsrtt t.aw
after the machines have done all their fine
work 1t will remain for human fingers to
complete the polishing process. The focal
length of the telescope cannot be decided
upon until the focal power Of the lens has
been established. but 1t Is estimated that 1t
will be between Sc and 60 feet. Beside being
an object glass, 1t Is also photograph glass.
The largest astronomical photograph lens
previously made has been but twenty-four
inches In diameter, but it is expected that
the present one will accomplish unheard of
triumphs In revealing wonders of the starry
armament.
Judge Widney said tina. through it the
moon will look as If only 100 miles away,
It's surface their presence will be revealed
through its aid: The glass, 1t is thought,
Will also settle the question as to the sup
posed signals of light which the inhabitants
of Mars are understood to be making to the
people of the earth,
The observatory for which this new teles-
cope is intended is to be about - or 15 miles
from Los Angeles. on part of the Sierra
Madre mountains. known as Wilson peak.
1t is claimed to be better sight for obser-
walton than the Lick observatory. 1t is
about 5000 feet above sea level. and is free
from the mists and fogs which roll in through
the Golden Gate and spoil many chances of
observation with the Lick telescope.
The atmospheric conditions altogether are
said to be more favorable for astron omical
search than at the former place.
Mr.. E. F. Spence. after whom the observa-
tory is to be named, is wealthy Californ-
ian. He is president of the First National
Bank Of Los Angeles, and has given $4,000
toward the observatory. Daniel Freeman is
an extensive ranchman, who has contributed
1900 toward the same object. Judge Wild
ney is a trustee of the endowment funds for
the advancement of the liberal arts. agricul-
tural. theological and medical branches Of
the University Of Southern California. He
has come with his family to reside for a year
education in the Boston University, his cid
est daughter will study singing in the New
England Conservatory Of Music and two
ununn ahi1drau will ha n6upatad at the