Dr. C. R. A. Wright on the Determination of 



230 



20-0 



7-0 



5S}" { 



21 



24 

 46 



Various pe- 

 riods up to 

 100 hours. 



•018 

 •018 

 •012 



)- 



•017 

 •017 

 •009 



nil. 



017 

 •017 

 •009 



nil. 



In nearly every instance the observed quantities of hydrogen 

 and those calculated from the quantity of electricity passing, 

 after subtracting the amounts due to "diffusion discharge/' 

 either coincide or do not differ by more than *001 milligramme 

 of hydrogen, or about 0*01 cubic centim., an amount of vari- 

 ation not outside the probable errors of measurement. In 

 the few cases where the difference reaches *002 or '003 milli- 

 gramme, the observed amount is always less than the calcu- 

 lated quantity, the cause being that the temperature could 

 not be kept absolutely uniform, and consequently the loss of 

 hydrogen by " diffusion discharge " is a little underestimated, 

 the normal value of the rate of diffusion discharge being a 

 little increased through the effects of heat-convection (§ 79). 

 Some half dozen other experiments were made in which 

 slightly greater differences were observed, always in the same 

 direction, viz. deficiency in the amount of hydrogen collected ; 

 in these experiments the temperature fluctuated more than 

 in those above cited, and hence the results are not quoted, 

 being vitiated by the increased effect of heat-convection. 



From these numbers the final conclusion may be fairly 

 drawn, that when water is electrolysed the mass decomposed is 

 always proportionate to the quantity of electricity passing, no 

 matter how great may be the time it takes to pass, i. e. no 

 matter how small is the actual current employed, thus 

 comfirming and amplifying the results obtained by Buff 

 above quoted ; so that the universal validity of Faraday's 

 law may fairly be taken as being established. On the other 

 hand, the recent experiments of Guthrie and Boys (Phil. Mag. 

 [5] x. p. 328, Nov. 1880) show that a glass vessel filled with 

 dilute sulphuric acid or other electrolyte, and suspended by a 

 wire in a rotating magnetic field, is urged to a move by a 

 force producing torsion in the wire varying as the product of 

 the conductivity of the electrolyte into the relative speed of 

 the magnets compared with that of the fluid set rotating 

 whirlpool-fashion inside ihe glass vessel by induction ; and it 

 is supposed by the authors that, in this case, no electrolysis 

 occurs, although currents circulate in the fluid. The absence 

 of electrolysis, however, in these experiments, is not only 

 unproved but is highly improbable. At any given instant any 

 two opposite points on the inner surface of the glass con- 



