510 PROCEEDINGS OP THE AMERICAN ACADEMY 



On the Square-Bar Micrometer. By Seth C. Chandler, Jr. 

 (By title.) 



Professor Dolbear spoke of the philosophical structure of 

 the magnet, and exhibited a magnet made of brass upon 

 which iron had been deposited by the action of a galvanic 

 current. 



Professor Searle read a paper by William A. Rogers, enti- 

 tled, " Observations on the Flood Rock Explosion." 



Seven hundred and eighty-sixth Meeting. 



November 11, 1885. — Monthly Meeting. 



The President in the chair. 



The Corresponding . Secretary read letters from Messrs. 

 Cullum and Morison, acknowledging their election into the 

 Academy. 



The President announced the death of Dr. William B. 

 Carpenter, recently nominated for Foreign Honorary Mem- 

 bership. 



Professor Marquand exhibited and explained the operation 

 of a new logic machine invented b}^ himself. 



Seven hundred and eighty-seventh Meeting. 



December 9, 1885. — Monthly Meeting. 



The President in the chair. 



The following papers were presented : — 



Experiments upon the Determination of the Temperature of 

 Metals as a Function of their Mass. By William A. Rogers 

 and Austin L. McRae. 



On Atmospheric Refraction. By Edward C. Pickering. 



Mr. Whiting showed experimentally a new method of de- 

 termining the rate of vibration of a tuning-fork. 



Mr. Chandler called the attention of the Academy to an 

 error in the formula relative to the ring micrometer. This 

 error had been repeated in several editions of Bruno's Spheri- 

 cal Astronomy. 



