The Roanoke daily times. (Roanoke, Va.) 1895-1897, 1896-08-29

Cambridge, Mass. August 21.-It is
probable that the big lenses, which Alvin
Clark has made for tt.e University of
Chicago's mammoth l-erkes telescope,
,rill he shipped TO their destination some
time this fall. The lenses have been
finished for some til e, and the question
of shipping them now lies with the off
cialS of the University of Chicago, and
not with Mr.. Clark. The delay is caused
by the fact that the building which is to
receive the glass is not yet completed,
although il should have been done some
time ago.
The tuh- and machinery of the telp-
sec &c are all ready and have been g" fur
about two years, but the lenses are of
such priceless value that it Is not
thought best to ship them until they can
he sent direct to their ultimate resting
place 81 that they will have to 90 through
only one journey. The building will
probably he com plcted this fall. If it is,
the glass will then he shipped at once
but il not. the glass may not he sent until
next spring, ;,s, owing to the brittleness
caused by the cold weather, il is not
thought best as II rule to move large lem
Scs like this in the winter, ii it can he
avoided.
Even if shipped in the warm weather.
the care which will be take,a OF the glass
will la something remarkable, and the
chance of breakage reduced almost Ia an
impossibility. Each len>c will first he
taken AMI sewn up in Gotten flannel, to
prevent amy possibility of scratching the
surface in handling. Ii will then he
placed in large wooden box filled with
the finest curled hair, closely packed in on
every side so that it i impossible for the
glass to make the slightest movement.
This box will then he sealed up and
placed inside Il second box, the space he
tween the two being filled in either with
excelsior or with small springs made es-
pecially for the purpose. When each lens
has been packed separately in this way,
they will both he ready for shipment to
Chicago, and this shipment will be made
in parlor car. chartered especially for
the purpose Mr.. Clark and one or two
assistants will make the trip with the
lenses, and ut least one of them will he on
the watch day and night To see that they
receive no jar
70 II person who is not familiar with
what these lenses, are. such extraordinary
precautions might seem hardly necessary,
but as matter Of fact it would hardly
he possible to take tod great care OF
them. They represent years and years o.
patient work by the man who is undoubt-
edly the finest workman of his class in
the whole world; work which the ordinary
mind would he almost ut Il loss to com
prehend. 1t will however. give some
idea of what has been put into them when
it is stated that Mr.. Clark worked on the
lenses for more than year after they had
reached such n state of perfection that
the most finished scientist could not have
told. either by examination or by meas
urement, that tuvy We're not perfect in
every way The lenses are the largest
ones in the world, being forty inches in
diameter, while those Of the great Lick
glass, which i the largest at present set
up, are only thirty six inches in diameter.
In this case this also means that the
Nerkes instrument + the most powerful
glass, although this need not be neccssa
rly So for this glass has been tested and
found To he Il perfect one, that ii has
the proportional light gathering capacity
which it should have. 1t is doubtful
however, if the glass will really prove a
tenth more powerful than the Lick glass
owing to the difficulty of securing the
proper atmospheric conditions. This is
n more important matter with IA large
glass like this than with Il smaller one.
The tests OF this glass which were made
II while ago 10y Prof. kcclcr, of the Uni
versity of Chicago, with Mr.. Clark. were
necessarily extended over II long time for
this very reason as it was only on rare
| occasions that the conditions could he Sc
| cured Tor making Il proper test. IL is con-
| Sidered extremely doubtful whether con
| ditions will ever he obtained which will
| allow of the development OF the full
| power of the glass. For this reason il is
| probable that the glass will continue to
| lie the finest in the world. Theoretically
| there Is no reason why one should nSJ be
| made of almost any size, hut i'll practice
the chance of there being conditions
| which would allow of the DEVELOPMENT of
| the full power of glass larger than this
| one would he 50 slight that there is no
| great likelihood of one ever being made
| Just at present the finished lenses are
| placed away in Il paSSageway AT the back
of ii cellar in which Mr.. Clark does most
| of his work. y couple of large velvet
| cases have been made for them, and in
these they rest. looking like two great
| shining moons when seen from little
| distance, and as absolutely clear as the
| air itself when one approaches and looks
| through them. In spite of their immense
! value there i not the slightest danger of
| their being stolen, and the only reason for
their being locked up at all l. To prevent
their being injured hy malicious mischief
OF possible accident.
GOOD COMMON SENSE
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