140 Prof. Thomson & Mr M c Clelland, On Electricity. [Mar. 9, 1896. 



in the proportion of 2 to 1, increasing the number from 12 to 20 

 decreases it in the proportion of 1*44 to 1, from 20 to 28 in the 



-10 



10 



20 



30 





Fig. 10. 



proportion of 133 to 1, from 28 to 36 in the proportion of l - 25 to 1, 

 and from 36 to 48 only in the proportion of T01 to 1. 



With this bulb the effect is clearly marked. But in the 

 following experiments made with another bulb it is much less 

 noticeable. 



Number of leaves of tinfoil between the 

 bulb and the gas. 







2 



4 



6 



8 



10 

 14 

 18 



Time required to leak through 

 50 divisions. 



10 

 15 

 20 

 32 

 51 



In this case increasing the leaves from 2 to 6 increases the time 

 of leak in the proportion of 2 to 1, from 6 to 10 in the same pro- 

 portion, from 10 to 14 in the proportion of 1*6 to 1, and from 18 to 

 14 again in the same proportion. Thus, though there are traces of 

 the effect, it is not nearly so marked as in the preceding bulbs ; 

 we therefore conclude that the different rays are emitted by 

 different bulbs in different proportions. We have always found 

 this effect most marked in the most efficient bulbs, i.e. the bulbs 

 which produced the greatest leakage. 



We have in conclusion much pleasure in thanking Mr E. 

 Everett for the assistance he has given us in the preceding ex- 

 periments. 



