310 Scientific Intelligence. 



bearing of this phenomenon upon the Hall effect. The paper 

 includes a mathematical discussion of the subject by Boltzmann. 



On the Electromotive force developed in metal plates, carrying 

 a heat current, by a magnetic field ; by Walthee Nernst. — 

 This paper is a continuation of the work of Ettingshausen, by a 

 student in the laboratory of Kohlrausch. 



On the effect of Magnetism upon electric discharges in rare- 

 fied gases by Ludwig Boltzmann. — A flattened Geissler tube was 

 placed with its broadest section perpendicular to the lines of 

 magnetic force. Two glass tubes leading out of the magnetic 

 field served to connect the electrodes of a galvanometer. The 

 apparatus thus imitated the arrangement used by Hall in the in- 

 vestigation of his phenomenon. A transverse effect was discovered 

 analogous to that in metals. Air behaved as bismuth or gold. 



Observations upon the electrical conductivity of metals by 

 means of the induction balance ; by A. Oberbeck and J. Berg- 

 mann. — The authors show that Hughes's balance in general is not 

 a trustworthy instrument. Using an electro-dynamometer in- 

 stead of a telephone, and thin plates of metal they obtained 

 good results. 



Theory of the induction Balance ; by A. Oberbeck. — Math- 

 ematical discussion. 



On the electrical conductivity of pure water and its tempera- 

 ture coefficient ; by E. Pfeiffer. — The effect of the chemical con- 

 stitution of the glass confining vessels is noted ; also, change of 

 resistance with time and other conditions. 



Electrical relations of Rock Salt; by Ferdinand Bratjn. — 

 Its dielectric constant is studied. It was found to behave as an 

 isotropic substance in this relation. It conducts electricity 

 from 11 to 23 times better than paraffine. 



Studies of Salt Solutions ; by C. Bender. 



Two fundamental investigations upon the laics of Pyroelec- 

 tricity ; by Editard Riecke. 



On Hydrogen superoxide arising in electrolysis of dilute sul- 

 phuric acid at the anode ; by Franz Richarz. 



On the applicability of Joide's law to electrolytes ; by Hans 

 Jahn. 



Maqnetic circular polarization in cobalt and nickel ; by H. 

 E. J. G. Dubois. 



Gliding of the electric spark on the surface of water; by J. 

 Spiess. — This is a study of Lichtenberg's figures on the surface 

 of water which is covered by lycopodium. 



On the influence oftdt/a violet light on electrical discharges; 

 by H. Hertz. — The author shows that ultra violet light increases 

 the striking distance and length of spark of a Ruhmkorff coil. 

 If one draws apart the poles of a Ruhmkorff coil so that the spark 

 no longer passes, and then lights an electric light from one to four 

 meters distant, the spark again passes and stops, when the electric 

 light is extinguished. 



On the compressibility of dilute salt solutions ; by W. C. 

 Rontgen and J. Schneider. 



