64 J. Campbell's Astronomical Observatory. | 
It is hardly necessary to say that the foregoing arrangements 
are altogether local, and on any other site would be varied accord- 
ing to circumstances, 
2. 
: iv 
A, Reading room. —B, Observatory.—C, Observer's seat.—D, Reading table.—E, Pier of the we 
Upon the bed plate before mentioned, is placed a circular rail, 
twelve feet in diameter inside, three inches wide and one inch 
West Point Foundry, in one piece, and turned in a lathe, so that 
the bearing should not only be a true circle, but also smooth 
and level. 
The dome is twelve 
feet in diameter, inside, 
the base being a coun- 
terpart of the curb, which 
constitutes the bed plate. 
It is built in the usual 
manner with ribs, sawed 
to the proper circle, of 
well seasoned pine, that 
it might be light, and 
with ‘great care, that it 
might be an exact hemi- 
sphere. 
Two stout ribs cross 
inches wide a three | | i 
braced together to ONE Sectional view of the interior of the Observatory: a 
