Revolving Telegraph. 103 
grooves, and falling into the blank chamber by their own 
weight. They are raised by means of ropes passing 
over pullies in proper situations, and running down into 
the observatory. The upper chambers of this case have 
circular openings or windows, of two or more feet in di- 
ameter, which are closed as occasion requires by the 
above mentioned blinds. At night, lamps are to be fixed 
in the chambers; and, as one or other light, or the whole 
number, are obscured, so signals are constituted distinct 
from those of the telegraph itself. The United States’ 
flag may surmount this tower, and may, if necessary, be 
made accessory to the general communication. 
It is scarcely necessary to mention, that the machine 
must be sufficiently elevated above all adjoining build- 
ings, so as to be conspicuous in every point to which it 
may be revolved. 
When the machine is fixed permanently in a large 
town, the building on which it is elevated w ould be per- 
haps best constructed of an hexagonal or octagonal 
form, by which means, as many windows of observation 
may be connected with the observatory ; and, if the room 
is made of brick or stone, it might be easily vaulted, so 
as to secure it from fire, (which might destroy the machine 
above,) and render the circles of rotation in the roof, 
more solid and secure. 
The rotation of the machine is easily accomplished in 
the observatory by one or two persons, by means of an 
horizontal bar passing through the shaft. 
The advantages of this telegraph, I conceive to be 
1. Its simplicity; for by the proper obscuration of the 
thirteen chambers of the semicircle, all the letters of the 
alphabet, &c. may be signified. It is, I think, capable 
of being effected with one shutter only, in place of two, 
as above recommended, even without the upper case or 
tower, but certainly in conjunction with it. I have not, 
however, matured the plan completely. 
