The copper country evening news. [volume] (Calumet, Mich.) 18??-1907, 1897-06-08

Perfect Adjustment at Lake Geneva,
VISIT Will He Presented to the Uni
versity Of Chicago In July.
In swathing of cotton, curled hair.
tissue paper and flannel. the lenses for the
great Yerkes telescope at Williams bay,
Lake Geneva, Wis, arrived In Chicago
one morning recently. The big crystals
came in special Wagner car, and guard
consisting of Alvan @. Clark, the maker,
and corps of assistants, took turns watch.
ing that no harm came to the precious
freight
The lenses went from Boston over the
Lake Shore road, and reached the Van
Buren, street depot at 1885 o'clock I'm
mediately an engine was attached to the
car and it was taken over the St. Charles
Air Line tracks TO the Northwestern rail
road and went on the way TO Lake Geneva
station, the nearest station TO the observa-
tory. On the car with the lenses was
George C. Walker, trustee of the Univer-
sity of Chicago, and several officials of the
railroad company, for the property is of
great value and had been guaranteed TO
be delivered in safety. AT Lake Geneva
station specially constructed wagon had
been arranged for 70 haul the glasses over
the six miles Of road TO their journeys
end.
Professor Clark went along to put the
lenses in place and see that all Is right be-
fore returning home. Speaking Of his
work In making the crystals he said
"These lenses are for the largest astro-
nomical telescope In the world. The order
for their construction was given nearly
eight years ago by Charles Il. Yerkes, who
not only presents them to the University
of Chicago, but has built the observatory
and placed In IL the apparatus connected
with 1t. The principal lens is Al Il inches
In diameter and weighs 200 pounds. The
exposed surface when in place will be 40
inches In diameter, u inches being taken
up by the casing. 1t Is double convex, 23s
inches thick at the center and three -fourths
of an inch at the edge. The inner lens
Is OF flint glass, concave form, e inches
thick at the center and 2 inches at the
case. 1t weighs $40 pounds. The focus is
90 feet
1.-The glass out Of which these lenses
were formed was cast in solid block at
the great factory in Mantois France. 1t
was made in 1890, but finishing work was
not begun on it until two years later.
"For five years the process of forming
and testing the lenses has been going on.
The work has been done by a small force
of men, but it was constant, requiring the
utmost patience and care. The deviation
of the breadth of strand of a spiders
web would be fatal to the purposes of the
glass The crystal had first to be exam
ined to see IL 1t was without flaw, and,
after this, 1t went TO the grinding room.
For two years sand, fine steel and emery
were used, then the finest jewelers. |
rouge and beeswax for another year or |
more All this time tests were made to |
detect any inequalities. During the last |
stages the lenses were set in 90 foot |
tube, so / know that the object glass and |
It's mate are perfect
The lenses are worth sos, 900 and are in |
sured up to full value. The telescope was
ready for use by the astronomers of the !
observatory on the day following the ar
rival of the lenses A special train carried |
he trustees of the University of Chicago, |
President Harper, members of the faculty |
md number of invited guests to inspect
he great instrument and its powers. The
ormal presentation by Mr.. Yerkes will
axe place at the convocation in July.
Among the advantages which may be
expected to accrue to science from the
of this telescope will be better
ABILITIES for photographing sun spots. 1t
S better adapted for Investigations of this
haracter than any other existing instru-
nent, not only on account of its large
perturo, but particularly on account of
Is great focal length. The image of the
un at the focus of the telescope is nearly
inches in diameter and is therefore par
icularly well adapted for work on the de-
ails of the suns surface. Times
Herald.