iOi Description of a 
By its capability of rotation, one machine is adequate 
to convey signals from a centre to every point of the com- 
pass ; and hence is peculiarly adapted for large towns, 
especially for our seats of government, 
3. By the mutations of which it is capable, it is impos- 
sible to detect the intelligence communicated; for sig- 
nals can be equally adapted to figures, letters, words, or 
sentences, and the key may be changed ad infinitum, 
4. By a slight modification it would probably be well 
adapted to vessels of war, as a permanent or temporary 
appendage to one of the upper yards. Six chambers, in 
place of thirteen, would, I think, supply every requisite 
signal, particularly with the aid of a few flags ; or the up- 
per case or tower alone, with an increased number of cir- 
cular windows might readily be elevated at the summit of 
the mast, or be carried out to the extremity of a yard, as 
the steering sails are, by means of a boom, and no doubt 
by the changes that could be made, would answer every 
object at sea. 
I have gone upon the supposition, in the account of the 
above machine, that all the windows in the semicircle are 
exactly similar; as I have heard it objected, that some 
difficulties might arise in the signals by a mistake in the 
observer of the chamber closed, I shall point out a mode 
by which this may be obviated, although this must arise 
from inexperience and inattention, and is therefore on a 
footing with the possible mistakes of every other tele- 
graph. 
My plan is the following : To have each chamber dif- 
ferently constructed on each side the central one. Thus 
suppose the central chamber to be circular, the others 
might be as follow : 
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1 3 3 4 5 6 7 8 9 10 il 13 13 
