120 
Ordinary Meeting, April 5th, 1859. 
Dr. J. P. Joule, Vice-President, in the Chair. 
Mr. Curtis and Mr. Henry Bowman were appointed 
Auditors of the Society’s accounts for the year. 
The Chairman exhibited several slips of paper, having 
messages inscribed upon them by Professor Thomson’s new 
electric telegraph apparatus. In these specimens the marking 
consisted of a succession of minute perforations, produced by 
sparks from an inductive coil apparatus while the paper was 
gradually drawn through the machine. The sparks are 
directed to the paper by a fine platina wire affixed perpen- 
dicularly to a light arm attached to a small magnetic needle 
suspended within a coil of wdre. The directive tendency of 
the needle is made very great by means of adjacent steel 
magnets. So long as either no current or an uniform 
flow passes through the coil, the perforations go on in a 
straight line. To produce signals, temporary electric currents 
of longer or shorter duration are transmitted. The magnetic 
needle carrying the platina wire is thus deflected, causing the 
line of perforations to assume the shape of a succession of 
letters V of various width and at various distances asunder, 
and in this way letters and words are indicated by the use of a 
given code of signals. The chief advantage of this system of 
telegraphic recording is that it gives clear legible signals 
when a “relay” is entirely thrown out of action by inductive 
embarrassment. It has also the advantage of showing clearly 
signals superimposed on earth currents. The signal, super- 
imposed either on the large swell or wave^ of induction or of 
an earth current, is like a ripple seen distinctly on a large 
wave. The Chairman stated that Professor Thomson had 
recently discovered the means of giving a surer direction to 
the electric sparks, and of producing a very considerable 
increase in the size of the perforations produced by them. 
He also remarked that the system above described was similar 
in principle to that employed by Professor Thomson in 
Proceedings — Lit. & Phil. Society — No. 14.— Session, 1858-9. 
