December 5, 1902.] 



SCIENCE. 



90^ 



In accordance with the provisions of the 

 new constitution of the Academy, the officers 

 of the Section for the year 1903 were elected 

 at this meeting. They were : Vice-President 

 and Chairman, Professor James F. Kemp, of 

 Columbia University; Secretary, Dr. Edmund 

 O. Hovey, of the American Museum of Natural 

 History. Edmund O. Hovey, 



Secretary. 



relation to the current strength and the dura- 

 tion of the electrolysis appears to be less 

 simple. 



Solutions containing radium impart ac- 

 tivity to both anode and kathode, but this ac- 

 tivity decays very rapidly, falling off half its 

 value in about 35 minutes. 



S. A. Mitchell, 

 Secretary of Section. 



THE NEW YORK ACADEMY OF SCIENCES. SECTION 

 OF ASTEONOMY, PHYSIOS AND CHEIMISTKY. 



At the meeting of the Section on November 

 3, Mr. G. B. Pegram read a paper discussing 

 some experiments of his on the electrolysis of 

 solutions of radioactive salts, in course of 

 which he found that when a solution of a 

 thorium salt is electrolyzed, using platinum 

 electrodes, a temporary radioactivity is im- 

 parted to the anode rather than to the kathode, 

 which is remarkable in view of the fact that in 

 the air near dry thorium compounds a nega- 

 tively charged body, correspond_ing to the 

 kathode, becomes radioactive, while a positively 

 charged body, corresponding to the anode, is 

 not made active. The activity of the anode 

 used in the electrolysis of a thorium nitrate 

 solution can become nuich more intense, for 

 a given extent of surface, than that shown 

 by a thick layer of thorium oxide. 



The solution under electrolysis rapidly loses 

 its power of imparting radioactivity, so that 

 after four hours of electrolysis with a current 

 of half an ampere, a solution of 20 g. of thorium 

 nitrate in 100 c.c. water had lost 95 per cent, 

 of its power of imparting activity to the anode. 

 This radioactivity of the anode increases for 

 a while after being taken out of the solution, 

 then its intensity falls off at the rate of half 

 its value in eleven hours, which has been shown 

 by Professor E. Eutherford to be the rate of 

 decay in the case of surfaces made active by 

 exposure to the emanation from a dry thorium 

 compound. The radiation is not homogene- 

 ous, as is shown by a study of its absorption 

 by successive layers of metal foil. 



The activity of the anode seems to increase 

 directly with the concentration of the solu- 

 tion for short periods of electrolysis, but its 



THE ELISHA MITCHELL SCIENTIFIC SOCIETY. 



The society held its 143d meeting Tuesday 

 evening, November 11, in Person Hall, Uni- 

 versity of North Carolina. 



Dr. J. E. Mills presented a paper on a 

 ' Suggested Modiiication of the Law of Du- 

 long and Petit,' in which he stated that if y 

 denote the ratio of the specific heat of a gas 

 at constant pressure to the specific heat at 

 constant volume, it was shown that y could 

 be defined in terms of the translational energy 

 of a molecule and the internal energy of the 

 molecule. Hence y has a meaning for liquid 

 and solid bodies capable of a physical inter- 

 pretation. Upon this basis there was deduced 

 an equation governing the specific heat of a 

 body and applicable to the solid, liquid or gas. 

 The deduced equation holds so far as measure- 

 ments have been made. If the theory be true 

 it will explain certain discrepancies and ex- 

 tend the law of Dulong and Petit. 



Dr. W. C. Coker spoke of a ' New Species 

 of Mosquito.' In abstract he stated that, 

 while studying the mosquitoes of South Caro- 

 lina in the summer of 1901, larvEe of peculiar 

 appearance were found in a small pool near 

 a well, and brought into the house. After 

 about three days imagoes of both sexes 

 emerged which proved to be of a new species. 

 They were taken alive to Washington and 

 there studied by Mr. D. W. Coquillett, who 

 describes them as a species of Psorophora. 

 He gives them the name P. howardii in honor 

 of the well-known entomologist. Dr. L. O. 

 Howard. 



Eggs of this species obtained by Dr. Howard 

 from the individuals taken to Washington 

 proved to be practically identical with those 

 of P. ciliata procured by Dr. Coker in South 



