376 PROCEEDINGS OF THE AMERICAN ACADEMY. 



A standard metre from M. Tresca, of the French. Com- 

 mission, was exhibited. 



" On a Method of obtaining a Permanent Record from 

 Foucault's Pendulum." By Charles R. Cross. 



." On Comets of Minimum Perihelion Distance." By Ben- 

 jamin Peirce. 



The following papers were read by title : — 



" Substituted Benzaldehydes." By J. Fleming White. 



" Dimethyluric Acid." By H. B. Hill and C. F. Mabery. 



Professor Watson presented to the Academy the works of 

 M. Cialdi on the movement of waves and littoral currents. 



Seven hundred and thirty-first Meeting. 



May 12, 1880. — Monthly Meeting. 



The Vice-President in the chair. 



A letter was received from Mr. Clarence King, acknowl- 

 edging his election as Associate Fellow ; also, a letter from 

 Dr. A. Schaffranck, announcing the establishment of the 

 Natural History Society of West Virginia, at Wheeling. 



Professor Alfred G. Greenhill, of Emmanuel College, Cam- 

 bridge, England, at the request of Professor Lovering, spoke 

 of the estimation with which Professor J. Willard Gibbs's 

 work in thermodynamics is regarded in England, and said 

 that the scientific opinion is that Professor Gibbs has ad- 

 vanced the subject more than any other man in late years. 



Professor Greenhill presented to the Academy copies of 

 several of his own papers. 



Professor Pickering presented the following paper by 

 title : — 



" On a Mechanical Attachment for Equatorial Mountings 

 to Facilitate Sweeping in Right Ascension." By D. P. Todd. 



Professor Peirce read a paper on comets of minimum 

 perihelion distance. 



The following paper was presented by title : — 



" The Columnar Architecture of the Egyptians." By 

 Waldo S. Pratt. 



