Astronomy. 297 
The balance magnetometer has also a needle 12 inches in length. It 
has a cross of wires at each end, attached by means of a small ring of 
copper. The axis of the needle is formed into a knife edge, the edge 
of which passes as nearly as possible through the center of gravity of 
the unloaded instrument. There is also a mirror above the knife edges 
of the needle, whose plane is perpendicular to the magnetic axis. The 
needle rests by its knife edges upon agate planes resting upon a marble 
se. 
Fox’s deflector, for the purpose of measuring the inclination and in- 
tensity, was made by Mr. George, of Falmouth. 
_ The observatory is also furnished with a standard barometer by New- 
man; a dry and wet bulb thermometer; Daniell’s hygrometer ; self- 
registering thermometer ; Osler’s anemometer and rain gauge. 
About 200 volumes, mostly of astronomical observations, were pre- 
sented by different societies and astronomers of Europe, and 650 vol- 
umes were obtained by purchase, forming thus the nucleus of an astro- 
nomical library. 
us, then, we have at last a naval, if not a national, observatory. 
As respects the number, dimensions, and probably also the quality of 
its instruments, it has few equals in Europe. The public are anxiously 
looking for the fruits,of this noble establishment. May their reasona- 
ble expectations not be followed by disappointment. 
First Report of the Director of the Cincinnati Observatory, 
Prof. O. M. Mrrenent, 1845.—In May, 1842, the Cincinnati Astronom- 
ical Society was fully organized, and in June following, Professor 
Mitchell started for Europe to purchase a telescope. At Munich, he 
found an object glass of 12 inches aperture, which had been tested by 
Dr. Lamont, and pronounced one of the bestever manufactured. This 
was subsequently ordered to be mounted, and was purchased for $9437. 
The instrument arrived in Cincinnati in February, 1845. The corner 
stone of the observatory was laid by the venerable John Quincy Adams, 
in November, 1843. The observatory is 80 feet long and 30 feet broad, 
and is situated upon a lofty eminence to the east of the city proper. 
The front of the building presents a basement and two stories, while in 
the center, the building rises three stories in height. The pier is built 
of stone, and is grouted from its foundation on the rock to the top. 
The equatorial room is 25 feet square, and is surmounted by a roof so 
arranged as to be removed entirely during the time of observations. 
The hour circle is 16 inches in diameter, and reads by two verniers 
to 28. The declination circle is 26 inches in diameter and divided on 
silver to 5’, reading by verniers to 4”. The instrument has five com- 
mon eye-pieces, and nine micrometrical, with powers varying from 100 
to 1400. 
Srconp Serizs, Vol. I, No. 2.—March, 1846. 38 
