Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1889-04-21

the hill on which it stands. The institu-
ton referred to is the Allegheny Observa-
tory, and although known all over the
scientific world for the discoveries made by
it, the average citizens notion of the work
done there is rather vague.
Some have an idea that every favorable
day man looks at the sun through teles-
cope and piece of smoked glass and is
thus in some way enabled to set his watch
and give the correct time to the public.
Others imagine that they who spend their
time within its mysterious walls sleep all
day and pass the night reveling in star
clusters, comets, nebul@ and other wonder
full things, which entirely remove them
from ordinary mortals. An astronomers
life is not so fanciful as this, however. In
order to better acquaint the people of
Pittsburg and Allegheny with the instru-
ments and work of an institution better
known to the scientists of Europe than the
Iron City, of which we are so proud, this
article has been written.
FROM SMALL BEGINNINGS.
An institution for astronomical investiga-
tion was first talked of in the early part of
1859. The idea met with great favor, for
subscriptions began to be paid in, and in
1860 the Allegheny Astronomical Society,"
ordered of Henry Fitz refracting telescope
to be of 13 inches aperture, and about the
beginning of the year 1862 the telescope was
in place and in actual use. The Civil War
stopped further progress, and after its close
the corporation transferred their interest to
the Western University of Pennsylvania,
on the condition that they should support
the institution and endow chair of Astron-
omy.
The observatory building was then very
small compared with its present size. In
shape it may be ikened to large letter L,
placed backward, with the longer line rum
ming north and south. and the shorter ex-
tending west from the southern end of it,
Beginning at the NORTH we have the divi-
sions of the building in succession as fol-
lows: Rolling shed, covering the siderostat,
dark room, +" bedroom and machine shop,
drawing-room, assistants room, directors
room (at the angle), computing room" or
main Office, dome and transit room. Origin
ally there was nothing but the dome and the
computing room. Subsequently the ''time
service" was established and the transit
room containing the transit instrument and
two clocks was added. Since then various
additions have been made, the latest being
the dark room, with the siderostat just
north of it, used for the study of heat radi-
alton, particularly from the moons surface,
and for sundry other purposes.
THE INSTRUMENTS USED.
The equipment of the observatory may be
described under four heads:
The instruments used in the time service
the transit, chronograph and time pieces.
The large and small telescopes.
Galvanometer, spectro-bolometer and other
apparatus for special research.
The library.
The time service is the most important
work of the observatory, and does the gener-
al public the most good. Electrical signals
are continually sent out to the railroads from
Philadelphia to Chicago, by which their
clocks are kept going exactly right, and to
the cities of Pittsburg and Allegheny, for
which the observatory receives compensa-
tion, which serves to meet the running ex-
penses of the institution. The instruments
used in the time service may be divided into
two classes: First, the instruments actually
used to keep time and distribute it, consist
ing of two chronometers, sidereal clock, a
mean time clock, which gives the electrical
signals; with another mean time clock to be
used in case of accident to the standard
mean time clock, and the necessary electric
al apparatus to distribute the electrical
signals; second, the instruments used to de-
termine how much the clocks are in error.