132 Prof. J. Zeleny on the Ratio of the Velocities of the 



charged in succession to —60, + 72, and + 74 volts, and these 

 are repeated several times. From the deflexions obtained 

 when the 4-72 and +74 volts were used, the exact voltage 

 is found by interpolation which would give the same numerical 

 deflexion as was obtained with the —60 volts. 



The ratio of the potential values thus found, plus the cor- 

 rection necessary to reduce this to actual potential gradients, 

 gives the required value of the ratio of the two ionic velocities. 

 By using different velocities for the gas-blast, determinations 

 are made by the use of entirely different sets of potential 

 values. 



The following table gives the values obtained for the ratio 

 of the velocities of the two ions in the various oases used at 

 atmospheric pressure. 



Table III. — Katio of Velocities of Ions. 



Gas. 



Velocity of Negative Ions. 



Velocity of Positive Ions. 



Air. N and 



1-24 + -005 

 1-24 ± -005 

 1-23 ± -01 

 1-14 ± -01 

 1-15 ± -01 

 1-00 ± -005 

 1045 ± 015 

 0-985 ± -015 

 1-105 ± -01 



Oxveen. 



Nitrogen. N 



Hydrogen. H 















The probable errors given include only the errors in 

 determining the voltage ratio that it was necessary to use to 

 obtain the same quantity of the two kinds of electrification ; 

 and do not include any errors made in determining the correc- 

 tion that had to be applied to this ratio to reduce it to the ratio 

 of the potential gradients actually existing in the apparatus. 



In a mixture like coal-gas, where there are probably 

 several sets of ions, the value obtained may correspond for 

 the most part to the set having the greatest A^elocities, 

 depending upon how much greater these are than the others. 



On account of the large volume required, and on account 

 of the nature of the apparatus, no attempt was made to obtain 

 the gases very pure, especially since a small amount of impurity 

 cannot affect the result sensibly. 



The number and kind of gases used was necessarily limited 



