Specific Charge of the Ions emitted by Hot Bodies. 555 

 Tantalum. Positive Ions. 



s. 



H. 



Y. 



X. 



ejm. 



•449 



4650 



200 



•59 



145 



1 -449 



4650 



400 



•46 



175 



"551 



4850 



122 



115 



135 



•551 



4850 



160 



•925 



115 



•551 



4850 



200 



1-225 



257 



•551 



4850 



122 



1-55 



245 



•551 



4850 



160 



1-375 



253 



Average value ... <?//;> = 189, Corrected ... e/on—^l. 





™/H= 51, 



m/H= 32. 



The first two measurements were made on one strip and 

 the succeeding five on another. The first measurements are 

 probably not so reliable as the others on account of tLe 

 smallness of the deflexions. If we take the last three together 

 as representing the final steady value we find ejm (average) 

 252, corrected ejm 400, corrected m/H 24*2. Whereas for 

 the initial values the third and fourth give : — average ejm 125, 

 corrected ejm 199, corrected m/H 48'4. Here again the 

 ratio of the initial and final values is 2 to 1 as in the case 

 of gold. 



Tungsten. 



The tungsten used was in the form of filaments taken 

 from a new tungsten lamp. On account of the fact that it 

 was impossible to obtain the material in the form of strip 

 we should expect, as in the case of osmium, that the curves 

 would be very flat and the maxima not sharply defined. 

 The case was, however, worse than this, because the curves 

 were very irregular in outline and usually exhibited more 

 than one maximum. These were not due to the simultaneous 

 emission of more than one kind of ion, as they were present 

 just the same in the absence of the magnetic field. The 

 most plausible explanation seems to be that the positive ions 

 are emitted by some impurity which is liable to be irregularly 

 distributed about the filament. A number of attempts were 

 made to estimate the value of ejm from the displacement of 

 what appeared to be corresponding points in the patterns. 

 There is a good deal of uncertainty in this procedure, so that 

 it is perhaps not to be wondered at that the results obtained 

 do not show a very satisfactory agreement. They are given 

 in the following table : — 



