134 Prof. Thomson & Mr M e Glelhmd, On the Leakage of [Mar. 9, 



electrode from A was about 5 centimetres, and the length of the 

 electrode about 4'5 centimetres. The bulb was placed so that the 

 negative electrode was perpendicular to the plane of the hole in 

 the side of the tank, and its prolongation passed through the 

 centre of the hole. The discs in the chlorine tube were placed 

 opposite the hole with their planes parallel to the normal to the 

 plane of the hole. 



The results of these experiments are plotted in the curve in 

 Fig. 2. The abscissas are proportional to the distance of the middle 



-10 



10 



20 



30 



40 



50 



60 



Fig. 2. 



point of the discs from the point A of the bulb. The ordinates on 

 the dotted curve are proportional to the time required to leak 

 50 divisions, those on the continuous curve are proportional to the 

 square roots of these times. The continuous curve is a straight 

 line, passing through a point on the axis which corresponds to a 

 point C, 7 cm. behind A. Hence this experiment shows that the 

 times required for a given leak are proportional to the squares of 

 the distance of the discs from G, or that the rate of leak is 

 inversely proportional to the square of the distance from C. This 

 suggests that the Rontgen rays originate chiefly in the neighbour- 

 hood of G. There is no evidence of any corning from the glass in 

 the neighbourhood of A, though this is brightly phosphorescent. 



