Delaware gazette and state journal. (Wilmington, Del.) 1883-1902, 1886-12-09
THE LICK TELEsCOPB.

Arrangement for shipping thc |
$4,000 Leusea-Delicate Grinding. |
Boston Transcript
The two great lenses for the Lick tele- |
scope, on which the Messrs. CLARK of
Cambridge, have been SO long at work,
are now practically completed, and will
soon be sent to their destination. The
plan adopted for shipping the double
lens, worked out by Captain Fraser, is as
follows: The two glasses will first be
wrapped separately in fifteen or twenty
thicknesses of cloth drawn very tight.
The cloth will be cotton, and in order to
make it soft and perfectly free from grit
it will be washed many times and
thoroughly beaten. Next to the cloth
will come n thick layer of cotton batting
and then layer of paper. box
made of wood and linen with
felt will contain the glasses when
SO prepared, the felt lining OF the box
I coming next u the paper. The lenses
With their covering will be packed tightly
| in this box. The shape Of this box will
conform to the shape of the lenses. The
felt will be attached with glue, 30 that no
nails will he anywhere near the glass;
Outside OF this wooden box and enclosing
i ~ wall bC bllOA4k bbGuA IVA ubSNh bhO
shape of cube. The wooden box will
be tightly packed into the steel box with
curled hair. To enclose this steel box
| will be still another steel box or chest,
4 and the inner steel box will be kept from
touching it by large number of spiral
\ springs covering the whole interior Of the
outer steel chest. This outer chest will be
packed with asbestos, to render il fireproof,
l h1Al, ~ ha aknal hnWou will 10
made alright and waterproof. The
outer chest will be suspended by pivots
in o strong wooden Frame and contri-
vance has been adopted for turning the
chest one-quarter around every day dur
ing its progress to California. This is to
prevent any molecular disarrangement in
tho glass, and to avoid the danger OF po-
larization, it being feared that the Earring
of the train will disturb the present ar
rangement of the molecules unless the
position Of the glass is Jaily changed and
all lines Of disturbance thus broken up.
The glass will be insured for its full
value-or rather its coat--$5l 600, and
all the precautions mentioned are taken
to prevent any accident to it. II would
probably be impossible to replace it, as
Fell. who cast il, aud the elder Clark, who
4 l ktouLANi Avs ult lON1 Oll lub Rlh6l
! will be shipped by express.
There is something almost romantic IL
, the design aud construction of the mon
ster Lick telescope. Being the creates
work of the kind ever undertaken, pre-
senting difficulties that had never before
been encountered; inviting and sufferin,
drawbacks and disnsietH that seemed Il
be sufficient to stagger the most per
eli Oh at1I tt.,h lit AL.
: from day to day by whole world o
! anxious observers hoYtred over an
i careHsed by the united wisdom of gen
! eratiOnth lens hes come into the woFl
Z with its great cyclDpaHn eve ready t
pierce the mysteries of the heavens
t Captain ThomsF Fraser, superintendent
k Of the observatory, furnishes som
Z hitherto unpublished and highl
1 interesting information corctrnin
e the grinding Of the crown-glai
g lens, and the plan adopted Il
:, transporting il from CRinbridgepor
d Mass, to SAP JoHe. On tie subject
d the grinding he says that the close
measurement at command was IL
Il0, 000tn parto an inch; but in Rrindin
the great lens it was discovered that eve
this intinitesiInal fraction was too lerg
= A still tiuer measurement was required
4 reducing the lens in nuiHberless plates
thickness Itself nnequal) that won
le exactly concentrate parallel rays Of lig
g. filling circle three feet in diameter to
ia point little larger than a pin.
"a order to reduce the fine measur
g ment already at command, the fl
a. lowing ingenious arrangement was el
le ployed by Alvin Clark Il So1
II makers of the lens. A gas jet was plac
al before mirror, which sent the rays
b. light through telescope to the great lei
al thus magnifying the rays. The magnih
I'd light, passing through the great lens, "
Il still further immensely magnifed, Al
after having passed through this lens,
was observed through a second telesco
and thus further magniied. In this W
N. the least failure of the great lens to &C
ca centrate perfectly was detected, and the
a was also determined the amount of gil
lis in it, at any given point, that had to
IN ground of in order to secure a peri,
M focus. Thus measurement Of I
he 1900, 000th part Of an inch was secur,
les 1t took very little grinding to remove
Of small thickness Of glass from a Civ
ed point, gentle rubbing with the thu,
up being sufficient, as the glass is softer Ii
he common window glass.