The Saint Paul globe. (St. Paul, Minn.) 1896-1905, 1897-07-05

yatory stands on the crest of a range
of hills in Delaware county, two miles
from this city. 1t has a revolving
dome eighteen feet in diameter. The
tube of the telescope referred to is
tWenty-eight feet long and it is moved
about by means of clock work.
Persons who have read of recent as
Economical feats may remember that
it was the lens of this telescope which
was used by Prof. Percival Rowell, the
famous astronomer at Flagstaff, Arr
zCna, when he made his marvellous
observations Of the canals of Mars. A
comprehensive statement of the facts
regarding the observatory buildings
and their contents is the following
which has been written for this paper
by Prof. Henry B. Evans, instructor in
astronomy at the University of Penn
sylvania
The University of Pennsylvania has
dedicated to the cause of science it's
new astronomical observatory. The
latter is very suitably located on the
west of the city limits q Philadelphia,
beyond the influence of the smoke and
scot of the factories and the vibra-
lions of the steam and electric rail-
roads.
The ground on which it stands was
presented to the university some years
ago for the purpose for which it is
now used by the late Reese Wall Flow
er, from whom the observatory derives
its name. The original intentions of
the dCnnor were not carried out, how
ever, until two years ago when the
present director, Prof. Charles S. Doc
little, then professor of mathematics
and astronomy at Lehigh university,
was called to the similar chair at Phila-
delphia. Under his direction has been
added to the possession of the univer-
sity Of Pennsylvania, one of the finest
ana best equipped institutions for as
trCnomical research in existence.
FIRST and foremost in this equipment
IS the big equatorial telescope with
its eighteen-inch lens, mounted in a
separate dome capped building of it's
own. All of the Instruments are from
the makers of the big Lick and Yerkes
telescopes, and in this, their latest pro-
duction, they have introduced every
convenience which mechanical ingenu-
ity could devise for the assistance and
comfort of the observer. The lens
which Is the largest one in this country
east IF Washington, was made by
Brashear in Allegheny and formed part
of his exhibit at the worlds fair in
1898
Mr.. Brashear is the only man in the
world who has developed the art of
grinding glass to such perfection that
he can produce an absolutely fiat sur
lace. lie can grind glass correct to
any given o& line within one millionth
Of an inch. 1t would be natural to
suppose that a lens of his make would
be of a high standard of excellence.
The ore he has ade for the University
of Pennsylvania has been pronounced
by experts to have no superior. The
telescope is provided with the ordinary
eye-pieces, a screw micrOmeter for
close meas urements, a spec rOscope wi h
prisms, gratings, Photographic attach
mentS, etc. 1t stands on a pier Of
solid masonry, sixteen feet in height.
seven feet Of which is underground;
the whole rests on a solid bed of
stone and is totally unconnected
with the building which surrounds and
shelters it.
Near by the home Of the equatorial
is the transit building containing the
mathematical instruments. In one end
of this is a four-inch zenith telescope
of superior finish and design, which the
director uses in carrying on his obser-
vations for the determination of the
variation Of the position of the north
pole. The latter does not remain fixed
at one definite spot on the surface of the
earth, but moves slightly according to
somewhat complicated law. It's
whole range of motion, however, can
be included within a circle of sixty feet
in radius, and, therefore, to determine
its path accurately a long series Of
most accurate observations extended
over long period of time, is neces-
sary. Such a series has been carried
on by Prof. Doolittle with most accu-
rate results at his former observatory
at Lehigh university, and such a Sc