Brief Historical Sketch of the Telegraph. 293 
sure. These six boards are capable of exhibiting thirty * 
six changes by the most simple and easy mode of work- 
ing them ; and by these the letters of the alphabet and 
the numeral cyphers are denoted. This telegraph, how- 
ever, was by no means considered as being free from ob- 
jections and inconveniences, and various contriyances for 
remedying these have been indented since that period. 
To give an account of all these would greatly exceed 
our limits ; we shall, therefore, content ourselves with 
mentioning a few of the principal of them. Mr. John 
Garnet proposed a very simple and ingenious instrument, 
which consisted merely of a bar or plank, moveable about 
a centre, round which a circle was described, having the 
letters of the alphabet and figures depicted round its cir- 
cumference. An index which corresponded with the bar 
enabled the operator to set it to any letter or figure he 
wished to communicate. A wire was fixed across the 
tube of the telescope used by the observer, which was to 
be brought to coincide with, or to be parallel to the bar ; 
then the letter or figure to be communicated was denoted 
by a small index at the eye end of the telescope, which 
contained a circle similar to that encompassing the cen- 
tre of motion of the bar. Another ingenious improvement 
was proposed in the Gentleman’s Magazine : it consisted 
of a semicircle of twelve feet radius : this was to be pro- 
perly elevated, divided into 24 equal parts, and each of 
these perforated with a circular opening of six inches in 
diameter. These apertures beginning from the left, de- 
noted the letters of the alphabet, except K, J, Y, X, and 
Q, which were omitted : the remainder of the holes were 
reserved for signals. The communications to be made in 
the day were pointed out by means of an index, and in 
the night by lamps. None of the preceding telegraphs, 
however, appear to exceed, either in simplicity, cheap- 
ness, or facility of working, that described by J. N. Esq. 
