Astronomical Observatory. 375 
bastion, at the N, W. extremity of the city ; and it enjoys 
on all sides a clear and delightful horizon. Its isolated sit- 
uation secures it from all agitation arising from the motion . 
of wheels, and the ground, on which it stands, though 
made, has had the consolidation of 200 years, and possess- 
es sufficient firmness for the masonry, especially as it repo- 
ses on a bed of sandstone. The observatory is a regular 
octagon, 63 French feet in circumference. It is exactly 
orienté ; its entrance is on the east, and opposite to it is a 
niche, which includes a moveable stair case, and accommo- 
dations for books. The - . N E., and NW 
faces have large windows, before which, within, are stone 
brackets, which have no communication with the building. 
Two similar brackets are placed at each extremity of the 
meridian. Each of these brackets as well as the two stone 
columns which support the trunnions of the transit instru- 
Ments, repose upon massive masonry,as does also the pedes- 
tal of the clock. The upper demi-circumference of the meri- 
dian, is exposed when the shutters are opened. The floor is 
raised two feet above the outside level, so that the air may 
pass freely under it.. The two floors are eleven feet apart, 
and above is a wooden capula, so solid that very sensible 
levels, placed upon brackets provided for them, remain 
perfectly at rest during many series of delicate observations 
of the heights of the sun or stars, taken with the circle of 
rda. This observatory is already furnished,—Ist with a 
transit instrument, by Ramsden, of three feet focus. Its 
vertical movement is extremely easy. It is at rest in eve- 
ry position, its axis passing through the center of gravity of 
the system, its equilibrium is perfect. The meridional po- 
sition of this telescope is verified by an object erected on 
the Gourten, a mountain distant 12,000 feet, when it is 
placed at an angle of 4°.23 with the horizon. 2d. The 
