CHAPTER III. 

 DISCOVERY OF CORPUSCLES. 



With the discovery of gaseous ions, we have evidently 

 lighted upon a new kind of particles about which nothing 

 is said in the chemistries; and, of course, the questions 

 immediately arise: What are these ions? Do they exist 

 only in gases? Are they molecules, or atoms, or, what is 

 most important to us, are they less than atoms? What is 

 the meaning of their electrical qualities? We may best an- 

 swer these questions by considering, now, the ionisation 

 produced by glowing metals or by carbon. 



The effect of this agency may readily be shown by means 

 of the apparatus shown in Fig. 11. It is a glass vessel con- 



To Electrometer 



Battery 



Battery 



Fig. 11. Apparatus for studying the ions from a hot wire. 



(51) 



