144 Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. On the Influence of Proximity on Voltaic Action. — Some 

 time ago Gore showed that when an electrolyte was used in the 

 form of a vertical column about three meters in height, the elec- 

 trodes being as far as possible perfectly similar, the difference of 

 pressure at its upper and lower ends, due to the action of gravity, 

 produced an electromotive force giving a feeble current on closed 

 circuit. Reasoning that if by producing pressure, gravity exerts 

 an influence on chemical and voltaic action, even an excessively 

 minute one, similar effects should be produced when a large mass, 

 either of metal or other substance, acts by gravity on a voltaic 

 electrode placed at the end of a horizontal column of electrolyte, 

 the author has made a series of experiments to test the question 

 and gives in his paper results which go to establish the correct- 

 ness of his conclusion. — Phil. Mag., V, xliii, 440-457, June, 

 1897. G. F. B. 



2. On the Action of Light on Chlorine and Hydrogen. — It 

 has been shown by Gautier and Helier that when equal volumes 

 of hydrogen and chlorine, both carefully dried, are submitted to 

 diffused daylight for ten or twelve hours, the quantity of hydro- 

 gen chloride formed corresponds to only about 2*55 per cent of 

 the mixture employed ; while if the gases be moist, the amount 

 of hydrogen chloride produced under precisely similar conditions 

 may rise even to 60 per cent. Exposed to diffused sunlight for 

 an hour, 6*7 per cent of the mixed gases entered into combination 

 when they were dry and 92 5 per cent when moist. Hence it 

 appears that when the vapor of water is present, the combination 

 is materially facilitated ; a result which the authors regard' as due 

 to the formation of intermediate products, for instance, hydro- 

 chloric acid. In subsequent experiments, the dry mixture of 

 gases was exposed to artificial light. Using an albo-carbon flame 

 at the distance of a meter, the light emitted being equivalent to 

 14*5 carcels, it was observed that after 237 hours 92'5 per cent of 

 the hydrogen and chlorine had combined to form hydrogen chlor- 

 ide. The rate of this formation increased at first, reaching a 

 maximum, after three hours exposure, of 28 per cent per hour. 

 Then it decreased somewhat rapidly. In no case, however, was 

 any limit to the combination indicated ; thus showing a marked 

 difference between the action of light and heat. The maximum 

 rate of formation is attained much sooner with sunlight than with 

 artificial light. The authors also observed, that the rate of com- 

 bination, after the maximum is passed, is not proportional to the 

 uncombined hydrogen and chlorine, since the hydrogen chloride 

 already formed, while it does not limit the action, exerts a de- 

 cided retarding influence upon the union. Moreover, when the 

 chlorine is in excess, the combination is more rapid. Thus if the 



