994 



Prof. 0. W. Richardson on the Positive 



field was then reversed, and the curve with points thus : — X, 

 taken. The field was again changed back to its original 

 value and the position of the first maximum redetermined. 

 The points are shown thus: — ~x}. The position of the first 

 maximum was found to be unchanged within the limits of 

 experimental error. 



The curves with broken lines, points ©, represent similar 

 observations taken after six hours heating. Although the 

 positions are displaced a little, the displacement of the maxi- 

 mum due to the held is the same as in the preceding case. 

 In the experiments represented in this diagram the values of 

 the numerical quantities were: — V=200 volts, H = 4(500 



lines per cm., 3 = *50] Cm., and 2^ = 1*98 turns. These 



values, which are the same for both sets of observations, give 



m 



»6J and m = $7'0. 



Similar sets of observations were taken after 18, 21. 36, 

 42, and 60 hours heating. As, except for the temporary 

 broadening mentioned above, which was observed after 



eighteen hour- heating, all the curves were similar in 

 character, it will he sufficient to give the last one of them. 

 This is shown in fig 9, and represents the results obtained 



alter sixty liours heating. The data pertaining to this curve, 

 a^ well as the other observations mentioned, are given in 

 the following table : — 





Potassium 



Sulpfa 



to Positive Ions. 





Substance. 



Time 

 hours). 







(ions;. 



v 



(volts). 

 9 i | 



H 



I lines per 



cm • : . 

 4650 



1 L-0635 



cm.). 



1-21 



c/m 

 (E.M. 

 units). 



m 

 (11 = 1). 



Platinum . 



•50] 



390 



24 S 



n 



1 



■503 



200 



4650 



1-14 



346 



279 



>> 



•; 



•501 



206 



405( ) 



100 



266 



363 



K.,SO t ... 







•501 



200 



4650 



■99 



261 



37 



„ 



6 



•501 



200 



4650 



•90 



261 



37 



„ 



24 



•486 



200 



4050 



•93 



261 



37 



„ 



36 



•48G 



200 



4050 



•95 



272 



35-5 





42 



•486 



200 



4650 



•94 



266 



363 





60 



•486 



200 



4650 



•91 



266 



36-3 











Mean value of m for K 2 SO ; 



= 36-5 



It will be seen that the different values of elm and m for 



