APP. H.] RADIUM 219 



illumination of the lines of magnetic force and the magneti- 

 sation of light " may be regarded as a prophetic flash of 

 genius. 



A not altogether dissimilar flash has already been 

 referred to, when Crookes hinted prematurely that in the 

 cathode rays we had something like corpuscular light, and 

 also like matter in a fourth state, neither solid, liquid, nor 

 gaseous. For, whether quite right or not, he was far 

 more right than the critics of those days who presumed 

 to deride him. 



APPENDIX J. 

 On the /2-rays from Radium. 



Magnetic deflexion of Beta-rays. 



The following diagram illustrates the spreading out 

 into a sort of spectrum of the Beta-rays or electric 

 particles shot out with different velocities from radium. 

 Some are only slightly bent, being very speedy. 

 c did <** 



a represents the source of radiation ; 



b an aperture through which the rays have to pass; 



c the impression which would be produced on the 

 photographic plate with a magnetic field absent, and 



d v d, d z the impress on the same plate due to the 

 deflected rays. 



