PHILOSOPHICAL SOCIETY OF WASHINGTON. 67 



Mr. G. K. Gilbert made a communication on 



THE HORARY OSCILLATIONS OF THE TEMPERATURE OF THE 

 ATMOSPHERE, 



in which he correkted barometric and thermometric changes and 

 rates of change in observations made at San Francisco and Phil- 

 adelphia in the equinoctial months of March and September. 



Mr. F. F. JuDD made a communication on 



THE WATERSHED OF THE ADIRONDACK REGION, 



giving results of a survey of the head-waters of the Hudson and 

 Rackett Rivers by Prof. Farrand N. Benedict in 18Y4, and 

 dwelling particularly on the feasibility and facility of converting 

 the numerous and extensive lakes in that region into reservoirs, 

 so managed as to greatly reduce freshets in the Hudson in the 

 spring, and supply the deficiency of water in the fall. 



Remarks were made by Messrs. Harkness, Henry, Powell, 

 and, Alvord. 



Mr. Elisiia Gray gave an 



exhibition of a telaphon, 



wnich he had invented, by which musical tones transmitted over 

 a telegraph wire can be responded to at a distant point. Several 

 tones of a dilferent pitch were transmitted simultaneously by a 

 single circuit from one room, and eacli responded to in another 

 room by a reed attached to an electric magnet and tuned to the 

 same pitch. With such apparatus several messages can be sent 

 at the same time by the same circuit, and at the place of reception 

 each would be distinguished from the rest by difference of tone 

 and by being responded to by a magnet whose reed was tuned 

 to the same pitch as that from which it had come. He stated 

 that messages had been thus transmitted successfully by a circuit 

 of 300 miles. 



He also exhibited other methods by which the- sounds could be 

 responded to ; in one of which a tune played in one room was 

 repeated by a diaphragm in another, with which an electrical 

 connection was made. 



