1869.] 



91 



[Davidson. 



and Proceedings, and offering a set of the Canadian Naturalist 

 in exchange. 



A letter from the London Antiquarian Society, acknowl- 

 edged the receipt of Proceedings, A. P. S., No. 80. 



Donations for the Library were received from the London 

 Geological Society, Essex Institute, Peabody Academy at 

 Salem, New Bedford Library, Greorge E. Ellis of Cambridge, 

 New Jersey Historical Society, Franklin Institute, Academy 

 of Natural Sciences, Philadelphia, and the Protestant Episco- 

 pal Church Hospital. 



The decease of Dr. Robley Dunglison on the 1st inst., aged 

 71, at Philadelphia, was announced by Mr. Peale, and on mo- 

 tion of Mr. Fraley, Dr. Pancoast was appointed to prepare an 

 obituary notice of the deceased. 



Professor Trego communicated an extract from a letter from 

 Mr. Davidson of the Coast Survey, to Mr. D. B. Smith of 

 Germantown, detailing the method employed to obtain the 

 recent determination of Longitude and the velocity of the 

 electric current between Cambridge and San Francisco. 



San Francisco Chrouograpli. 



Local circuit JQ®" 

 Local battery j@®= 



0. Sending pen. 



]. Eeceivingpen. 



San Francisco 

 relay 



Hly Earth at San 

 Tranoisco 



San Francisco, March 1st, 1869. 

 I give you the first written news not only of our telegraph longitude 

 success, but of the success of my plan for determining the time of trans- 

 mission of clock signals from my clock to Cambridge and back, over 7, 000 

 miles of wire, through 13 repeaters and a multitude of relays. Through 

 the liberality of the Western Union Telegraph Company, I had two 

 trans-coutiueutal lines placed at my use, and last night I succeeded 



