Chemistry and Physics. 421 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. On the Electric Conductivity of Gases. — The question 

 whether gases can conduct electrification, has been investigated 

 by Braun, under various conditions. He examined first, com- 

 pound gases at the moment of their formation, using (1) mixtures 

 of nitrogen dioxide and air and (2) mixtures of chlorine and 

 hydrogen ; their union being effected by the influence of heat or 

 of diffuse daylight. For the conductivity measurements, a Ley- 

 den battery was employed, having an electromotive force of about 

 4000 volts. No conduction was detected. In the second set of 

 experiments the gases were examined during the time of explosion, 

 a mixture of carbon monoxide and oxygen being employed, the 

 electromotive force used being that of from seven to twenty 

 Grove cells. Under these conditions, there appeared to be un- 

 mistakable conduction through the exploding gas. The last 

 experiments were made with gases heated to high temperatures, 

 about 1000° — 1200°, in porcelain tubes, the electromotive force 

 being that of a single Leclanche cell. It was observed that am- 

 monium chloride and cadmium iodide conducted well, ammonia, 

 iodine and hydrogen chloride conducted fairly, while hydrogen 

 iodide, hydrogen bromide and mercuric oxide (probably) conducted 

 only very slightly. No conduction at all could be observed with 

 carbon dioxide, water, or nitrogen tetroxide. In concluding his 

 paper the author expresses the opinion that the electric charges 

 of flames are due to the separation of positive and negative ions. 

 — Zeitschr. physikal. Chem., xiii, 155, February, 1894. g. f. b. 



2. On the connection betvieen the Atomic masses of metals and 

 the Crystallographic characters of their Isomorphous salts. — A 

 comparative crystallographic study of the normal sulphates of 

 potassium, rubidium and csesium has been made by Tutton with 

 a view to determine the relation between the atomic masses of 

 these metals and the crystallographic characters of their isomor- 

 phous salts. After an elaborate summary of the results obtained 

 the author concludes that " a regular progression is observed in 

 the crystallographical characters of the three sulphates under con- 

 sideration, corresponding to the progression in the atomic weight 

 of the metal which they contain. With regard to every property 

 whether morphological or physical, the rubidium salt stands inter- 

 mediate between the potassium and the caesium salt. The replace- 

 ment of rubidium by caesium, however, is generally accompanied 

 by a greater modification of the crystallographical characters 

 than when potassium is replaced by rubidium, the heavier atom 

 exerting an influence gi^eater than in mere simple proportion to 

 the increase in atomic weight. The comparative results for the 

 different properties are all in line with each other, the relations of 

 the amounts of change along the directions of the three crystallo- 



