TPxANSACTIONS 



^oba ^cotiau tiieititutc of Science, 



SESSION OF 1914-1915. 



The Distribution of the Active Deposit ok Thorium 

 IN AN Electric Field. — By G. H. Henderson, B.A., 

 B. Sc, Instructor in Physics, Dalhousie University,* 

 Halifax. 



(Read November 9th, 1914.) 



The problem of the distribution of the active deposits of 

 radio-active substances in electric fields is an old one and was 

 early investigated by Rutherford\ Russ", Kennedy^, and oth- 

 ers. In much of this early work no attempt at precision was 

 made and a considerable part of it was rendered of doubtful 

 value by faulty experimental arrangements. The problem 

 in the case of radium was more recently taken up by Wellisch 

 and ronson^ and by Wellisch^ and in the case of actinium 

 by Walmsley.^ 



It was felt that a similar investigation of the active de- 

 posit of thorium was timely and might throw further light 

 on the mechanism producing the charged condition of the 

 active deposit particles and on the conditions which affect 

 their distribution in electric fields. 



* Contributions from the Science Laboratories of Dalhousie University — (Physics). 



1. Rutherford, Phil. Mag., Feb. 1900, .Jan. 1903. 



2. Ru3s. Phil. Mig, June , 190S. 



3. Kennedy, Phil. Mag.. Nov. 1909. 



4. Wellisch and Bronaon, .A.m. Journ. S<-i. XXXIII, May 1912. 



5. Wellisch, Am. Journ. Sci. XXXVI.. Oct. 1913. 



6. Walmsley, Phil. Mag.. Sept. 1913. 



Paoo. & Tbass. N. S. iMsr. Set., Vol. XIV. Trws. 1. 



