326 THE GRAMMAR OF SCIENCE 



for the exercise of disciplined imagination. In the vague- 

 ness of our conceptions of ether and atom hes the ill- 

 explored continent which, by clearer definition, the 

 Galilei and Newton of the future will annex. But before 

 this annexation there is work for the unpretending pioneer 

 in helping to clear away the jungle of metaphysical notions 

 which impedes the progress of physical science. 



SUMMARY 



The physicist forms a conceptual model of the universe by aid of corpuscles. 

 These corpuscles are only symbols for the component parts of perceptual 

 bodies and are not to be considered as resembling definite perceptual equiva- 

 lents. The corpuscles with which we have to deal are ether-element, prime- 

 atom, atom, molecule, and ]:iarticle. We conceive them to move in the 

 manner which enables us most accurately to describe the sequences of our 

 sense -impressions. This manner of motion is summed up in the so-called 

 laws of motion. These laws hold in the first place for particles, but they have 

 been frequently assumed to be true for all corpuscles. It is more reasonable, 

 however, to conceive that a great part of meclianism flows from the structure 

 of gross " matter. " 



The proper measure of mass is found to be a ratio of mutual accelerations, 

 and force is seen to be a certain convenient measure of motion, and not its cause. 

 The customary definitions of mass and force, as well as the Newtonian state- 

 ment of the laws of motion, are shown to abound in metaphysical obscurities. 

 It is also questionable whether the principles involved in the current statements 

 as to the superposition and combination of forces are scientifically correct when 

 applied to atoms and molecules. The hope for future progress lies in clearer 

 conceptions of the nature of ether and of the structure of gross " matter." 



LITERATURE 



The views put forward in this chapter were reached when the author was 

 studying the laws of motion for teaching purposes in 1882, and were developed 

 for the purpose of college lectures in 1884 and subsequent years. A brief 

 account of them was published in 1885, on pp. 267-71 of Clifford's Common 

 Sense of the Exact Sciences, but the only published work in which the author 

 has found any indication of similar opinions, or from the perusal of which he 

 has received any help or encouragement, and the only work he can therefore 

 heartily recommend to the reader, is : — 



Mach, E. — Die Mechanik in ihrer Entwicklung, S. 174-228. Leipzig, 

 1883. 

 The reader who desires to see the bearing in a wider philosophica 

 aspect of this idealistic view of mechanism on life may consult : — 



