RECORDS OF MEETINGS. 741 



The following papers were read by title : — 



" On Linear Differential Equations of the Parabolic Type." 

 By M. M. Smith. Presented by Maxirae IlOcher. 



" The Spermatogenesis of the Myriapods. V. On the Sper- 

 matocytes of Lithobius." By Maulsby W. Blackman. Pre- 

 sented by E. L. Mark. 



" Concerning the Adiabatic Determination of the Heats of 

 Combustion of Organic Compounds, especially Sugar and Ben- 

 zol." By T. W. Richards, L. J. Henderson, and H. L. Frevert. 



" Concerning Position Isomerism and Heats of Combustion." 

 By L. J. Henderson. Presented by T. W. Richards. 



" The Determination of Small Amounts of Antimony by the 

 Berzelius-Marsh Process." By C. R. Sanger and James A. 

 Gibson. 



"The Determination of Arsenic in the Urine." By C. R. 

 Sanger and Otis F. Black. 



" The Determination of Arsenic by the Guthzeit Method." 

 By C. R. Sanger and Otis F. Black. 



Nine hundred and seventy-first Meeting. 



February 13, 1907. 



The Academy met at the Walker Building of the Massachu- 

 setts Institute of Technology. 



The President in the chair. 



There were present twenty-five Fellows and eighteen guests. 



The following letters were read ; From the Soci^t^ Imperiale 

 russe de Geographic, on the occasion of the eightieth anni- 

 versary of M. Pierre de Semenov ; from E. van Everdingen, 

 announcing his appointment as Director of the Netherlands 

 ^leteorological Institute ; from the Academic de Macon, enclos- 

 ing the medal of its centennial ; from the Seventh International 

 Zoological Congress, inviting the Academy to be represented by 

 delegates at its meeting in Boston, August 19 to 23, 1907. 



The President announced that the Rumford Medal had been 

 awarded to Professor Ernest Fox Nichols for his researches on 

 radiation, particularly on the pressure due to radiation, the 

 heat of the stars, and the infra-red spectrum. He then called 



