4 THE THEORY OF IONS 



dissociated, are charged with electricity and move 

 about ; such dissociated atoms are called ions. 

 Whenever a change occurs in the constitution of 

 molecules consisting of similar or diverse material 

 such ions constitute the nascent material. They 

 consist of one or more elements, and part at least 

 of the associated energy is in the form of electricity. 

 In a fluid or gas which is undergoing dissociation, 

 the ions or dissociated particles are in a state of 

 rapid movement, and their velocity varies more or 

 less with the temperature and other conditions. 

 Their movements are infinitely complicated owing 

 to the impaction of the ions one against another, 

 some having a velocity greater than others and 

 consequently a higher temperature. There is 

 however a mean velocity and temperature through- 

 out the particles, and a mean free-path ; and 

 although the rate of velocity differs for ions of differ- 

 ent kinds, ions of the same elements, under the same 

 conditions, travel at the same rate. 



Much as we know about matter, our knowledge 

 is finite, and it is certain that our present knowledge 

 is incomplete. The discovery of new elements has 

 shown that there are forms of matter whose existence 

 until recently was unsuspected ; that matter exists 

 from which force emanates in such a manner as 

 to show the close relationship of matter and force. 

 Some of these elements shed forth energy so long 

 as they endure, and, inert as they are chemically, 

 their radio-activity is enormous. Much speculation 

 about the nature of radio-activity and much ex- 

 perimental work has not yet solved the mystery 

 of the energy which emanates from such materials 



