﻿The Electrochemistry of Radioactive Bodies. 629 



decomposition voltage of the system under consideration has 

 been reached. 



When the magnitude of the decomposition voltage of a 

 radioactive metal is known, its position in the series of 

 electrochemical potentials can be determined, and thereby 

 light may be thrown on its chemical nature. This is im- 

 portant, because the purely chemical properties of the shorter- 

 lived radioactive bodies are so far only imperfectly known, 

 owing to the minute quantities with which we are compelled 

 to work. 



Experiments have already been undertaken by v. Lerch 

 on the separation of radioactive bodies electrochemically in 

 order to determine their places in the series of electrochemical 

 potentials *. One of the methods of electrolysis he made 

 use of in this work consisted in dipping a plate of metal in a 

 salt solution containing radioactive matter to bring about its 

 deposition on the plate. This process is a local galvanic 

 action, 



Just as copper is assigned a place in the series of potentials 

 between iron and silver, because it is capable of being deposited 

 on an iron plate but not in detectable amount on a silver plate, 

 so radium was placed between nickel and silver, because it 

 is deposited on the former but not on the latter. This con- 

 clusion, however, is not of itself justifiable if the considerations 

 discussed above are admitted. They would rather lead us to 

 expect that every metal is capable of causing the deposition of 

 every radioactive fx)dy to a greater or a less degree, but never 

 in amount less than can be detected by the methods of radio- 

 activity. 



This the author has succeeded in showing experimentally. 

 Every radioactive body dealt with — viz. radium, radium A, 

 radium B, radium C„ radium 2 , radium D, radium E, and 

 radium F; thorium X, thorium B, thorium C, and thorium D ; 

 actinium B, actinium C, and actinium D — is capable of being- 

 deposited on all metals, not excepting even gold and silver. 

 The experiments have been carried out in neutral solutions ; 

 for in acid solutions, with which previous experimenters have 

 for the most part worked, disturbances to the results of 

 electrolysis arise from the solution of the deposited body in 

 the acid. 



An account will be published in a later communication of 

 the amounts of the various products obtained under different 

 conditions by electrolysis, and also the arrangement of the 

 radioactive bodies according to their potentials. This series 



* v. Lerch, Ann. d. Physik. xii. p. 700 (1903) ; Jahrb. der Kadioakt 

 ii. p. 471 (190.5). 



