388 Intelligence and Miscellaneous Articles. 



2. The potential gradient in question decreases as the clear 

 width of the tube increases ; and 



3. Increases as the pressure increases, but more slowly than in 

 proportion to the pressure. 



4. For uitrogen quite free from oxygen it is, for pressures 

 between 4 and 8 mm., 1*4 times as much as hydrogen. 



5. A small admixture of oxygen with the nitrogen increases it ; 

 a small admixture of aqueous vapour with nitrogen produces no 

 change. — Wiedemann's Annalen, No. 2, 1895. 



PRIZE-QUESTION PROPOSED BY THE SCHNYDER VON WARTENSEE's 

 FOUNDATION FOR ARTS AND SCIENCES, ZURICH. 



The Schnyder von Wartensee'3 Foundation again proposes for 

 the year 1897 the following prize-question on problems in Physics. 



"As the numbers which represent the atomic heats of the 

 elements still show very considerable divergences, the researches 

 conducted by Professor H. F. Weber on boron, silicon, and carbon, 

 on the increase of the specific heat with the temperature, are to 

 be extended to several other elements prepared as pure as possible, 

 and also to combinations or alloys of them. The densities and 

 the coefficients of thermal expansion of the substances investigated 

 are further to be determined as accurately as possible." 



The conditions are as follows : — 



Art. 1. The treatises handed in by competitors for the prize- 

 question may be either in German, French, or English, and must 

 be sent in by September 30th, 1897, at the latest, to the address 

 given in Art. 6. 



Art. 2. The examination of the treatises will be entrusted to 

 a jury composed of the following gentlemen : — 

 Professor Pernet, Ziirich. 



„ A. Hantzsch, "Wiirzburg. 

 „ E. Dorn, Halle-on-the-Saale. 

 „ J. Wislicenus, Leipsic. 



„ Gr. Lunge, Zurich, as member of the committee 

 proposing the prize-question. 



Art. 3. The Prize Committee has at its disposal a sum of four 

 thousand five hundred francs, of which a first prize, of no less 

 than three thousand francs, will be awarded and minor prizes for 

 the remaining sum. 



Art. 4. The work to which the first prize is awarded remains 

 the property of Schnyder von Wartensee's Foundation, which has 

 to arrange with the author regarding its publication. 



Art. 5. Every treatise sent in must bear a motto on the title- 

 page and be accompanied with a sealed envelope containing the 

 author's name and bearing the same motto outside. 



Art. 6. The treatises are to be sent to the following address, 

 within the period named in Art. 1 : — 



"An das Presidium des Conventes der Stadtbibliothek in Zurich 

 (concerning prize-question of Schnyder von Wartensee's Founda- 

 tion for the year 1897)." 



