444 



Prof. W. C. Rontgen on Electrical 



correct that the M.P. is compelled to overcome a certain transi- 

 tional resistance, and that only the disposable potential-differ- 

 ence measures the quantity discharged. The latter shall, for 

 shortness, be denoted by D. P. 



Pressure 51*8. 



Pressure 109*7. 



Pot-cliff.' 



Discharge. 



D.P. |i Pot.-diff. 



Discharge. 



D.P. 



1462 

 1727 



2004 

 2199 

 2349 



2487 





 71 

 171 

 271 

 371 

 471 







265 

 542 

 737 

 887 

 1025 



1806 

 2094 

 2859 

 3396 



3684 







38 



208 



370 



522 







288 

 1053 

 1590 



1878 



Pressure 203*4. 



Pressure 294. 



2162 



2645 

 2859 

 3396 

 3684 





 45 



67 

 138 

 192 







483 



697 



1234 



1522 



2433 



2859 

 3396 

 3684 





 29 



72 

 105 







426 



963 



1251 



Pressure 391. 



Pot.-diff. 



Discharge. 



D.P. 



2775 

 3169 

 3684 





 24 

 65 





 394 

 909 



The first of these Tables, corresponding to the pressure 

 51*8, is graphically represented in fig. 2 ; the abscissa? denote 

 the quantities discharged, the ordinates the D. P. The curves 

 for the other pressures have a similar form. 



3. In a gas with a determined difference of potential, in 

 what manner does the amount of electricity discharged depend 

 upon the pressure? Dry air, free from carbonic acid, with the 

 potential-difference 3684, was examined in detail. 



Pressure in millims. of mercury 

 Amount of electricity discharged 



641-2 

 



466-4 

 41-5 



391-0 

 65 



294-0 

 105 



203-4 

 192 



109-7 

 522 



This Table is graphically represented in fig. 3 ; the abscissa? 

 denote the amounts of electricity discharged, the ordinates the 

 pressures. Other gases behaved similarly. 



In these experiments, as already mentioned, the difference 

 of potential was constant. But as, according to No. 1, with 

 different pressures the discharge ceases and commences respec- 



