274 Mr. H. F. Morley on Grove's Gas-Battery. 



The result in millimetres for the couple without platinum 

 plates was: — 



Nov. 13. Dec. 11. Jan. 9. 



Hydrogen 76*3 76'4 76*3 



Oxygen 49-9 49-7 49-7 



Practically the volume of the gas in these tubes was not 

 altered by diffusion. 



For the tubes which contained the platinum plates the lengths 

 were : — 



Nov. 13. Nov. 20. Dec. 11. Jan 9. 



Hydrogen 56*5 56*6 55*5 55*0 



„ calculated 56*6 56*4 55*75 54*9 

 Oxygen 34-4 34-2 34'2 



The second line is calculated from the first by least squares, 

 on the assumption of a uniform decrease of hydrogen. The 

 greatest error is \ millim. ; and 1*7 millim. has disappeared. 

 The oxygen seems to have been supplied by the air. 



II. On December 11 I joined the plates through a galvano- 

 meter of 6917 ohms resistance. The connexion through the 

 galvanometer was made without previously breaking the cir- 

 cuit ; yet a current was instantly shown ; after 19 hours the 

 deflection was 20J divisions. By comparison with a DanielPs 

 cell whose electromotive force I assumed to be 1*1, 1 found that 

 a deflection of 1 division indicated a current of '00000000056 

 electromagnetic unit. 



If we assume that the current in the short circuit is the 

 same as that passing through the galvanometer, an assumption 

 which later experiments show to be not far from the truth, we 

 shall find that 8 cubic millims. of hydrogen per week would 

 be required to keep up this current. Now 32 cubic millims. 

 have actually disappeared per week. The difference may be 

 partly due to the inaccuracy of the assumption just made, and 

 partly to the fact that some of the hydrogen combines with 

 oxygen that has found its way from the air into the hydrogen- 

 tube, the local currents thus produced not contributing to the 

 main current. 



III. An experiment similar to I., in which, however, the 

 gases were prepared chemically, and in which there was also a 

 gas-couple whose plates were not joined by a wire. The lengths 

 of gas, in millimetres, corrected as before, were: — 



For the couple with joined plates — 



May8. Oct. 4. Loss. Volume lost, in 



J cubic centims. 



Hydrogen 146-1 136*0 10*1 2'87 



Oxygen 648 62*7 2'1 -60 



