The Seattle post-intelligencer. [volume] (Seattle, Wash. Terr. [Wash.]) 1888-1914, 1899-11-19

which they had reached. After several
specimens have been found 10 be free
from bubbles the temperature Is reduced.
tie glass thickens, the crgctbie is opened
and a certain portion of the surface IS
SKINNED OF to get rid OF impurities The
glass Ia then stirred and the cooling Ia al
sowsd 20 proceed rapidly fer five or six
hours until the surface Of the glass enaits
a we3i-5efiued sound when il is struck
with an iron bar.
After this step IL Is necessary TO proceed
with annealing- The furnace is walled up
and cooling IS allowed to proceed. which
requires from four to six weeks. When
TIE crucihIe Is opened the glass Is found
10 have been broken into pieces Of varying
sizes. In order TO obtain q 9s2-pound flint
glass lens IL is necessary 10 fiud a block
which weighs nearly !. 30 pounds. and such
a block having been found among those
in the furnace IL Is removed and placed
upon car. Slabs OF glass are sawed from
two parallel sides in order 10 obtain pol
tshej surfaces that facilitate q perfect ex-
animation OF II. The striae in the surface
are removed. and IL after this the block
exhibits any defects at such depth that
they cannot be removed. IL is submitted
70 4 moiding which changes Its form and
brings the chief defects near the surface
The block Is placed in a mod Of refrac-
tory clay and put into a furnace and heat
sd 10 500 10 so degrees CentigTade. By
this means II becomes slowly heated and
softened until 1, assumes the form OF the
mold but IL must not become fused. or the
whole operation must be gone over again.
II the outcome OF the process Is success
ful. the glass is slowly anneaied and is
then taken from the mold and examined
anew. II any defects deep in the glass
are seen a second operation is begun with
a mold of another form. Finally, when
the glass is very pure and perfect, another
and final molding produces the plano-con-
yex lens After this comes another heat
ing and cooling. which takes two or three
weeks
AT this point the glass disks are taken
to the establishment of NJ. Gautier. where
the surfaces are polished with device
like that used in polishing the mirror ex-
cept that the slides have the curve that
is % be given to the disk. 4 long time is
required in polishing out the small imper-
fections, and finally the lens Is entirely
corrected and ready for mounting
The tube which carries the eyep!ece 10
supported by four wheels rolling upon
rails 1t is attached TO the telescope by
an adjusting screw, 492 feet in length,
which serves for putting IL in focus. In
the interior Of this tube another is mount
ed upon rollers. This inner tube il 3A
feet in diameter and Is moved circuiarly
by means Of ciockwork, through the me-
dunn Of tangent screw which fits into
the teeth OF circle fixed to its outer ex-
iremty. In this first circle which moves
upon four rollers Is a second circle which
carries two guides and In which slides
carriage having travel equal to a little
more than two minutes Of time This Is
actuated by screw. which causes the
motion In another clockwork. This car
riage Is provided with a system OF frames
having rectilnear motion that permits OF
giving the eyepiece different positions The
upper frame Is so arranged that II may re-
ceive devices for photography, nicrometry.
spectroseopy or a projecting apparatus.
The exact location of the telescope has not
yet been determined upon. but II will be
at the service of the exposition, and win
probably be placed somewhere where the
atmosphere is purer than that Of Paris.