Evening star. [volume] (Washington, D.C.) 1854-1972, 1896-06-12
HANDS OFF THE MOON!
Telescope That Will Bring 1t Within
u Few Miles.


u Few Miles.
From the Londcn Daily News.
The huge block of crystal which will be-
come the mirror for the great telescope has
safely arrived in Paris. If all goes well the
exhibition of 1900 will be able to boast of a
distinct feature. Whether the moons fea-
lures will be equally distinct is another
question. Prof. Loewy thinks not, but NJ.
Deloncle is still determined to carry through
his idea.
THE moon one YARD off" 1t was thus the
scheme Of the gigantic telescope was spoken
of in the papers, but NJ. Deloncle, however
ambitious he may be in Central Africa, pro-
tests that he never had so preposterous a
notion. He claims that it will be possible
to throw on to a screen views of our satel-
lite brought within distance of thirty-eight
miles. This remains to be seen. However,
everybody will wish NJ. Deioncle. and still
more especially his shareholders, every sue
cess in what one must still regard an
experiment.
The new telescope mirror Is the largest
ever made. 1t was cast at Jeumont, a manu-
featuring place and the last French station
on the line to Liege, Cologne and Berlin.
This splendid block of homogeneous crystal
weighs 1900 kilograms. Its diameter is
2.o3 meters, and in its present nearly rough
state it cost $1,000. OF course, 1t was con-
veyed 10 Paris in a special train. 1t was
wrapped up in heavy felt blankets. pro-
tected by hoops Of soft wood, with metal
tires. mounted on pivots. Thus packed, the
mirror was tightly wedged in case that
was placed in the wagon on bed of hurdles
and layers of hay.
For greater safety the train stopped only
once. a Tergnier, and went at as slow a
pace as a royal train, escorted by railway
inspector. 1t was insured to its full value.
The same afternoon it was removed from
the northern terminus to the workshop. The
mirror, before leaving Jeumont, went
second grinding he
ing as smooth as fine plate glass. But for
telescope purposes this sort of smoOthness
is roughness itself The finishing process
Will take two years and six months and by
more expeditions processes than any hitler
to in use, hich. moreover. will give greater
accuracy than anything known
Hitherto astronomical mirrors and lenses
have been polished by hand by slowly rub
bling the glass with the naked hand. some
times, but not always, moistened with oil,
albumen and other substances which are
the makers secret. The drawback of this
process is that the mere heat Of the hand
may cause the surface to warp.
The new mechanical process, of which
particulars are not given, will produce a
surface approaching true plane, within
one-ten-thousandth part of milimeter.
Even this marvellous finish will leave mar
gin, astronomers tell us, for errors. The
whole finishing process will cost $1,000. The
silvering Will not cost anything to speak of.
The mirror Will be mounted on two arms
ten meters long. and will be set in motion by
machinery of the usual sort. The rays
gathered from planetary space will be re-
Elected horizontally through a mammoth
tube sixty meters long. laid on piles of
masonry. The lenses OF flint and crown
glass will be l meter % centimeters, the
largest in the world, and the images, en-
larged 500 times, will be thrown on to a
screen, which thousands of people will view
at time.
The moon will, If all goes we'll, be brought
within thirty-eight miles, but 1t is most
whether Wi
prove correct. NJ. Loewy, the assistant
director of the Paris observatory, who has
submitted some splendid photographs of the
moon, believes that the limit of ninety-four
miles he has reached is the utmost prac-
ticable for a long time to come. Larger
images will be indstinct