38 SCIENTIFIC THOUGHT. 



the atomic view of matter. Similar uncertainties in 

 the definitions exist in both theories all through the 

 century, down to the most recent times. There are 

 those who still look upon both conceptions as merely 

 convenient symbolisms, as ideal instruments of thought 

 or scientific shorthand ; and on the other side we have it 

 as emphatically stated, that the question, What is ether ? 

 "is the question of the physical world at the present 

 time," " that it is not unanswerable," in fact, " that it 

 is not far from being answered," that " it is probably 

 a simpler question " than the other question, What is 

 matter ? l The whole domain of physical science is even 

 divided into two portions, the physics of matter and the 

 physics of ether, 2 and the older, more empirical, and 

 common - sense divisions, treating separately of light, 

 electricity, and magnetism, are assembled in one great 

 doctrine, the " doctrine of the ether." It is, indeed, 

 somewhat astounding, if not disheartening, to hear at the 

 same time from an authority who has done more than 

 any other living philosopher to enlighten us in these 



1 Professor O. Lodge, in the i 2 See inter alia Professor Paul 

 Preface to the first edition of j Drude's ' Physik des Aethers ' 

 ' Modern Views of Electricity,' (Stuttgart, 1894). In the Preface, 

 p. xi. " It is simpler," he con- p. vi, he speaks of the philosophical 

 tinues, " partly because ether is " desire of using the same fuuda- 

 one, while matter is apparently mental conceptions for the physics 

 many ; partly because the presence of the ujther as for the physics of 

 of matter so modifies the ether that matter, whereby it remains an open 

 no complete theory of the properties question whether it is more service- 

 of matter can possibly be given able to reduce the equations in the 

 without a preliminary and fairly physics of the aether to those ex- 

 complete knowledge of the pro- pressions which can be got from the 

 perties and constitution of undis- observable phenomena in the 

 turbed ether in free space. When physics of matter (the equations 

 this has been attained, the resultant of dynamics), or whether the 

 and combined effect we call matter opposite road can be chosen with 

 may begin to be understood." advantage." 



