﻿688 Non-Newtonian Mechanics, 



(2) For long ranges (20-80 m.) the values found were : 



m. B. A. 



20_40 -00040 -00027 



40-60 -00029 -00014 (?) 



60-80 -00010 (?) 



(3) The scattered radiation which has been deducted is from 



one-third to one-half of the primary. 



(4) The total numbers of ions produced in the atmosphere 



per second were found to be (A) 2*54 xlO 15 ; (B) 

 2*36 x 10 l \ The energy spent in ionizing is, there- 

 fore, only about 1/20000 of that expended in the bulb. 

 We are indebted to Mr. L. V. King for his kind assistance 

 in the long range measurements. 



LXVL Non-Newtonian Mechanics. 

 To the Editors of the Philosophical Magazine. 



Gentlemen, — 

 TF1HE defence which Dr. Tolmari, in the last number of 

 X the Phil. Mag., sets up against my criticisms is strange 

 indeed. He points out that his argument, even after I have 

 restated it in a form free from certain logical absurdities, 

 still contains an error. I readily admit the fact, but the 

 error is his, not mine; it is contained in his original argument, 

 which I was concerned to correct only in one point and for 

 which I have not accepted the smallest responsibility. 



Apparently he now admits that the argument was in- 

 sufficient, for in the revised form which he now puts forward 

 he introduces an additional assumption. To the assumptions 

 of the conservation of momentum and the Einstein space- 

 time transformation, he adds that of the conservation of 

 mass, which is not deducible from them alone. The work 

 of Epstein {Ann. d. Phi/s. xxxvi. p. 793) seems to show that 

 the additional assumption is unnecessary. 



In a footnote Dr. Tolman attempts to refute my main 

 criticism by a defence which I answered in the last paragraph 

 of my attack. I pointed out that arguments which are legiti- 

 mate in making deductions from general principles are not 

 always legitimate in establishing these principles. I see no 

 reason to withdraw my assertion that the application of the 

 principle of conservation of momentum to cases (such as that 

 of the Bucherer experiment) where the observer is situated 

 on one of the reacting systems is inconsistent with the principle 

 of relativity. 



I am, 



Leeds University, Yours faithfully, 



March 3 7 1912. NORMAN E. CAMPBELL. 



