164 SIR WILLIAM RAMSAY 



oxygen. The spontaneous change which it undergoes, more- 

 over, is accompanied by the emission of an immense number of 

 corpuscles, expelled with a velocity approaching that of light 

 in magnitude and which have a remarkable influence on matter." 



With the design of applying this immense and con- 

 centrated store of energy to the production of chemical 

 change, experiments were first made on the action of 

 radium bromide on water, then on the action of the 

 emanation on water and on a mixture of oxygen and 

 hydrogen. Giesel was the first to observe the fact of 

 the decomposition of water by radium salts, but Bod- 

 lander and later Ramsay and Soddy found that the 

 mixture of evolved gas contains an excess of hydrogen. 

 Ramsay now found that the action is reversible, but 

 that the velocity of decomposition of water by the 

 emanation is greater than that of the recombination 

 of the resulting gases. The rate at which water is 

 decomposed by the emanation presents a problem which 

 was found to be insoluble in the present state of 

 knowledge. 



The second paper referred to contains an account of 

 the action of emanation on solutions of copper and lead. 

 The details concerning the apparatus and operations 

 involved are very complicated, and every precaution 

 seems to have been observed against the introduction of 

 impurity and the possibility of error. The conclusions, 

 however, are of such fundamental significance that no 

 amount of skill and labour would be wasted in their 

 verification. For these experiments lead to the sug- 



