﻿98 Prof. W. A. Norton on the Fundamental 



neous axis of the disk necessarily implies loss of vis viva, and lie 

 calculates the supposed loss in a very peculiar manner. What he 

 means by saying that vis viva lost by impact of the axle on its 

 bearings is employed in heating the disk (alle iibrige lebendige 

 Kraft geht fur die Rotation verloren und wird zur Erwarmung 

 der Scheibe verwandt) we cannot pretend to understand. Such a 

 statement, if meant to be understood literally, would appear to be 

 contrary to the fundamental principles of thermodynamics. If, 

 however, though he certainly does not say so, Herr Meyer means 

 that impact of the axle on the bearings may produce vibrations of 

 the disk which in time will by viscosity be frittered down into heat, 

 he merely repeats one of many objections, long ago perceived by 

 ourselves, and also pointed out to us by others, an objection which 

 we have already at least partially met by experiment and calcu- 

 lation. [It may be well to say here that Professor Helmholtz, 

 nearly two years ago, very kindly detailed to us his objections, 

 making several valuable suggestions by which we have since en- 

 deavoured to profit, and which will be duly acknowledged when 

 we are in a position completely to answer these objections. This 

 will, we hope, soon be the case, as extensive additional apparatus 

 is now in course of construction.] 



There are various other parts of Herr Meyer's paper to which 

 we might easily take exception, especially the calculation he 

 makes (even supposing his assumptions to be correct) as to the 

 absolute amount of radiation to be expected ; but it would be 

 foreign to our present object to enter into such details. The 

 determination of radiation in absolute measure is an inquiry of 

 great importance, and we are glad to hear that it has been taken 

 up by Professor Neumann ; we believe that Sir W. Thomson 

 also has been working at it ; so that the question is now in good 

 hands, and will no doubt soon be definitely answered. 

 We are, Gentlemen, 



Yours &c, 



B. Stewart, 

 P. G. Tait. 

 January 1869. 



XIV. Fundamental Principles of Molecular Physics. 

 By Professor W. A. Norton*. 



IN a recent work by Joseph Bayma, S. J., Professor of JPhilo- 

 sophy, Stonyhurst College, England, in which a new theory 

 of Molecular Mechanics is ably set forth, I find a brief critique 

 of my theory of Molecular Physics, published originally in Silli- 

 man's Journal, and republished in the London and Edinburgh 

 * From Silliman's American Journal for September 1868. 



