105 
Revolving Telegraph. 
From the great difference between each, it can scarcely 
be supposed that chambers thus formed, if three, four, or 
live feet large, would not be sufficiently conspicuous at the 
greatest distance that telegraphic signals are communica- 
ted. It must be persons totally unfit for the situation, 
who could not easily acquire a knowledge of the cham- 
ber obscured. I say nothing further on this point, since 
experience perhaps is required to know exactly what 
figures are best adapted for distant view ; and it is only 
general principles I propose to establish throughout, 
which may serve as foundations for practical experi- 
ments. 
I shall now equally in a general point of view, give an 
idea of the manner of making or rather constituting the 
signals, since it will altogether depend on the arrange- 
ments agreed on in the key of the communications. 
I shall suppose the hour of communication arrived;— 
(it will probably be best to have certain fixed periods of 
communication;) the signal of commencement is hoisted 
throughout the line, successively, from first to last, none 
withdrawing his, until the station in advance has elevated 
it. This signal might consist of the fiag of the Union, 
were it not for the wind being often unfavourable to its 
proper display : hence, perhaps, it will be better to blind 
the upper chamber of the parallelogram or tower. This 
signal being made and withdrawn, the lower chamber 
may be darkened to signify figures, or both chambers may 
be darkened to imply letters, as the medium of correspon- 
dence. These preliminaries being settled, requiring no 
more time than is requisite to hoist the blinds, and ascer- 
tain if the next in succession has answered them, the same 
chambers serve now another purpose in the progress of 
correspondence. Thus the upper chamber closed, im 
plies the signal of error, and, of course, a repetition of 
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