180 PROCEEDINGS OF THE OAnADIaN INSTITUTE. 



currents of the telegraph system and the induced currents of the tele- 

 phone system are used simultaneously and without interfei-ence. 

 An application for a patent covering this invention was filed at 

 Washington in June, 1878, and the patent was issued in February, 

 1879. Among the claims in this patent are the following : — 1st. In 

 a branch line, or a derived line of a voltaic circuit, the combination of 

 a condenser, a telephone and apparatus for generating induced 

 currents for signalling purposes. 2nd. The combination of two or 

 more parallel telegraph wires with a branch line and condenser 

 attached to each of said telegraph wires and with a common ground 

 wire and with telephonic apparatus inserted in said ground wire. 

 He did not wish to detract in the least from the credit due to Mr. 

 Smith on the one hand for conceiving the idea, or from Mr. Edison 

 and Mr. Gill eland, on the other, for developing it. His desire was 

 simply to put the actual facts on record. With regard to the com- 

 mercial value of the " air telegraph " and the possible position it is 

 destined to take in commercial economy, he was not in a position to 

 speak, he simply knew that it had excited much interest among rail- 

 way men.* 



The President said that it was gratifying to learn that in 

 the improvements that had been made in the applications of 

 electricity and the patents that had been obtained much was 

 due to a Canadian. That Canadian was, though his modesty 

 did not permit him to mention it, Dr. Rosebrugh himself 



NINETEENTH MEETING. 



Nineteenth meeting, loth April, i886, the President in the 

 Chair. 



The following list of donations and exchanges was read : 



1. Das Echo, July 25th, 1885, August 7th, 1885, December 18th and 25th, 



1885, January loth, 22nd, 28th., 1886; February 11th, ISth, and 

 25th, 1886 ; March 4th, Uth, and 18th, 1886. 



2. The Spectator, March 2l)th, 1886. 



* A second paper by the same author, in continuation of this subject, was read before the 

 Institute on the 8th January, 1887. 



