PHILOSOPHICAL SOCIETY OF WASHINGTON. 65 



Mr. J. E. HiLGARD explained the construction of the new ane- 

 roid constructed by Goldschmidt, illustrating his remarks by ex- 

 hibiting one of the instruments in question. 



l)r. B. F. Craig read a communication 



ON THE WATER SUPPLY OP CITIES. 



35th Meeting. November 30, 1872. 



The President in the Chair. 



General W. T. Sherman gave an account of his travels in 

 Turkey and the Caucasus, recounting numerous observations of 

 general interest made by him in those countries. 



36th Meeting. December 11, 1872. 



The President in the Chair. 



The President stated that the meeting had been called a few 

 days earlier than usual for the purpose of introducing Professor 

 John Tyndall, of the Royal Institution, London, but that the 

 proceedings would be those of an ordinary meeting. The Presi- 

 dent then read a paper 



ON certain abnormal phenomena of sound in connection 



WITH FOG SIGNALS. 



Prof. Tyndall made some remarks on this subject, citing cer- 

 tain cases of abnormal phenomena which had come under his 

 own notice. 



Mr. S. Newcomb gave an account of 



THE PROCEEDINGS OF THE COMMISSION TO ARRANGE FOR THE OB- 

 SERVATION OF THE NEXT TRANSIT OF VENUS. 



5 



