466 TRANSACTIONS OF THE 



which can be used with safety in telegraphing ordinary messages. Also, 

 signals run together if we send them too quickly by the Baines telegraph ; 

 even on the tongue a hundred signals a minute cannot be distinguished. 

 They run together and produce one continued signal. 



Dr. Vanderweyde. — Ti at difficulty could readily be got over. 



Mr. Stetson. — On short lines perhaps there is no limit to speed of com- 

 munication, but on long lines there is — waves interfere or some other diffi- 

 culty presents itself. In a line 2000 miles long, by the old method, an 

 hour would be required for each signal. Fifteen words a minute is about 

 the present limit to the speed with which signals can be translated. 



Professor Reuben. — By omitting one-fifth of the letters we certainly 

 could save some time. 



Dr. Vanderweyde. — There are three effects produced by the electric 

 current — the magnetic, the chemical, and the physiological — and these are 

 produced at different distances. In the chemical telegraph, Baines' sig- 

 nals can be sent farther with the same current than in the electro-magnetic 

 one ; and after Baine's ceases to act through length of circuit, signals can 

 be received by the tongue. 



There are two kinds of electric currents — one has more intensity, the 

 other has more quantity. In the chemical telegraph more intensity is 

 required, consequently it will work at a greater distance. Yet Morse's 

 plan has great advantages peculiar to itself. 



In 1838, a key-board having ten keys was devised, and the shocks were 

 received through the fingers — the physiological effect being the signals. 

 At that time it was supposed that 1000 miles was the limit of telegraphing 

 with the electro-magnet — a few hundred miles more than that of the chemical 

 action — and a little further than signals could be received by the tongue 

 and fingers. Eighteen years ago it was proved possible to transmit signals 

 across rivers without the conduction of wires. The force of a current is 

 directly proportional to the diameter of the wire, and inversely to the 

 length. A disregard to this law caused the first experiments to send sig- 

 nals across rivers to fail. The battery was too small, but when a large 

 battery was used the needle, was evidently defective. The power of the 

 battery must be doubled if the length of the wire is doubled. But if the 

 diameter of the wire be doubled, the power of the battery need be but one 

 half as great. Consequently the power of the ba'ttery in the river experi- 

 ment had to be increased. If I want to transmit signals across a river, I 

 must place my plates farther apart than the width of the river, or else the 

 current will pass through the moist ground and not across the river, for it 

 will take the shortest course. 



Dr. Tteuben. — Whetston, in his experiments with a revolving mirror, 

 found that frictional electricity did not exhibit a line at the commencement 

 of the circuit, but did show one at the other extremity of the circuit. It, 

 therefore, passed as a flash instantaneously at the commencement, but at 

 the extremity of three miles of wire the flash was lengthened into a stroke 

 in the revolving mirror, showing that it took time to pass, or that a se- 



