The morning news. [volume] (Savannah, Ga.) 1887-1900, 1888-10-17
HOW BIG A LENS CAN BE.
THE GREAT LICK TELESCOPE NOT
RIG ENOUGH FOR SOME PEOPLE

Wiling TO OnOerGdke oOno OF l nat
size-He Would Try 6O-Inch Lens
if He Had Time.
From the Nelo York Sun.
Boston, Oct. 6.-This afternoon Alvin
Clark, the manufacturer of the great Lick
telescope lens, received a letter from the
President of the University of Southern
California, located at Los Angeles, asking
for information as to a 40-inch lens, and in
timating that an order for telescope to
eclipse that at the Lick Observatory would
soon be sent.
A correspondent who was present turned
his attention to the numerous lenses of diff
ferent sizes and in various stages of manu-
tacture while Mr.. Clark was reading the
letter.
He had Just been talking with the man
who had made eyes that could read patent
medicine signs on the moons rocks with re-
gard to the possibility for further advance
in astronomical researches, and he feared
the letter might make it necessary to
shorten his visit. Mr.. Clark's eyes twinkled
as he read the letter. Then, without word
of comment, he handed the missive to the
reporter and resumed the patient rub,
rub of a small lens glass on the polishing
block.
"What do you think of that?" he asked,
when the reporter had made areful men
tal note of the contents of the letter.
THAT is what | want to ask you, said the
reporter "Can you fill the order if it is
sentn
Certainly | CAM
But that is four inches larger than the
Lick telescope, is it not"
That may be, but what Of it," was the
amused answer.
Il hoI o. NcA Irv
savants that it was impossible to finish
lens any larger in diameter than that sent
to the Lick Observatory" the reporter
said
81 know such statement has been made"
replied Mr.. Clark, but do not endorse it.
I've been making telescope lenses now for
good many years, and l ought to know
something about it. If I can get the
glass the proper size there will be no
trouble in makinga lens 40 inches in diane
ter. I'd make 5-footer if my life was
spared long enough.
DO you mean to say that there is posi-
bility in the future of having telescopes
five feet in diameters"
Il don't sec why they should not be as
large as that. But mind you, it would take
about one mans lifetime to make such a
lens. In the first place, it would be neces-
sary to get piece of glass absolutely per-
feet in every way. the slightest flaw or
variation in density would spoil it for big
lens. 1t might be a generation before such
piece of glass could be manufactured. Then
it must be ground and polished Ivy hand. But
l believe such lens can be made, and l be-
lieve it will be maden
''Will it be of any practical advantage to
astrOnomersT
Certainly it will. ITS increased magni
flying power will be in proportion to its in
creased size. Take this 40-inch lens that
has been mentioned as an example. Its size
would be one-ninth larger than the
Lick Observatory lens, and it would make
given objects appear nine times larger or
niue times nearer. Increase the diameter of
the lens and you will increase the power to
examine worlds that have not yet been
seen. If lens five feet ia diameter is Sc
cured, it will bring the moon so close that
we can see every nook and Granny on its
surface AS for new stars, there is no limit
to the discoveries that could be made. 1t
would revolutionize astronomical re-
searches"
''Had you thought of making larger
lens than that in the Lick telescope before
you received this letterf'
"Oh, yes. lam not surprised at receiving
this letter, for when was i'll California a
year ago the president of that university
intimated that they should want larger
telescope than that on Mount Hamilton
astronomy in California. All sorts of peo-
pie are studying the science This 5-inch
lens | am polishing is for telescope l am
making for the president of that university.
1t is for his personal use, and he begged me
to MIKE it with my own hands, so | am
pegging away at it when l get the time. |
have also filled other small orders from that
state. In addition to those small orders |
have received no less than three letters from
different colleges asking if [ could make
4O-inch lens. | have written all
those persons that | was ready to accept
any and all orders for q 4O-inch lens. In
fact, was so sure that there would be a
demand for such lens that gave an order
60 the glass men in Paris to save for me the
first large mould that they succeeded in get
ting out. l may get it in few weeks and l
may have to wait months and weeks for it.
l heard the other day that they had cut
out two extra large plates, and were fin
ishing them for the exhibition next year.
If it's true, l shall secure them if money
will do itn
What causes this delay?"
ut is all in the casting" was the reply.
"All these lenses are made in France near
Paris. they are making them all the time
They melt up lot of glass, and when it is
oil the right consistency they set it aside to
cool. The glass is melted in huge pots, and
after every casting the pots are broken
away, leaving large mass Of glass. Then
they examine it and test it to SEQ if it is
suitable to split up into lenses. 1t must be
just right or it must be- melted over. They
have orders for all sizes Of lens, but they
do not consider those orders until they get
the block of glass. The least indication of
strl3 or sediment will show that it cannot
be used for larger lenses. Then thew break
IL up to see if they can use IL for small
oues There are generally enough imper-
teclons to ruin the block for large lenses
Ii none is visible to the eye, the block is
tested with the polariscope, to see If it is of
even density throughout. If all the condi-
tlons are perfect, then they will split up the
block and get out large lens in tue rough.
II they succeed in doing that, there is still
greater danger that it will be broken in the
first handling to get it down to the proper
size for grinding and polishing. After that
is accomplished the worst danger of break
age Is passed, though OF course it would re-
4 Ire the utmost skill and caution not TO
break it while putting on the finishing
touches.n
DO you break manyW
Lots OF them We do not break as many
now as we did at first, but in the course of
year we smash good many. Our expert
ence IN the past has opened our eyes n little,
so We can generally tell, before we touch
lens, whether or not it is sound. Take that
big Lick lens, for example. Perhaps you
relnemt er that we broke tho first one we
fled to finish, and that, doubtless. gave rise