98 The Rev. S. Earnshaw on some Remarks of Dr. Le Conte 



mathematical result with observation is entitled to at least equal 

 weight. The coincidence of the numerical result obtained from 

 experiments made for ascertaining the mechanical equivalent of 

 heat, adds nothing to the evidence, because these experiments 

 are apparently only another form of those by which the ratio of 

 the specific heats is determined. 



I take this occasion to advert to a result respecting the velo- 

 city of sound which I have given at the end of an article in the 

 Philosophical Magazine for April 1862. I have there found 

 that the rate of propagation depends, in some degree, on the 

 loudness of the sound. But after taking into account that I 

 had previously demonstrated the component character of the 

 waves of elastic media, it appeared to be a necessary consequence 

 that the greater or less magnitude of waves depends only on the 

 greater or less number of the components, and hence that the 

 velocity v in the cited formula is the maximum velocity in an 

 uncompounded wave. Now as there is no antecedent reason for 

 supposing that the maximum velocity is greater for one such 

 wave than for another, the right conclusion seems to be that all 

 the component waves, and therefore that all waves, great and 

 small, are propagated with the same velocity. It may, however, 

 happen that of two disturbances, made at the same time and at 

 the same distance from a given position, one agitates the air at 

 the first moment through a greater extent than the other; in 

 which case the effect of the former would reach the given position 

 by propagation sooner than that of the other. 



Cambridge, January 20, 1864. 



XIX. Reply to some Remarks of Dr. Le Conte in his paper on 

 the Problem of the Velocity of Sound. By S. Earnshaw, M.A., 

 Sheffield*. 



I AM not disposed to enter upon any general review of Dr. 

 Le Conte's paper printed in your Magazine of this month, 

 having in fact no leisure for the task ; but as some portion of it is 

 devoted to a review of three papers of mine which were printed in 

 your Magazine in the year 1860, it seems to be necessary that 

 I should take notice of his remarks and reply to them as far as 

 they concern myself. 



In page 8 of his communication, having given an abstract of 

 my results, he asks in disparagement of them, " Is it admissible 

 to assume the law of force, according to which the molecules of 

 the atmosphere act on each other, to be that of the fourth power 

 of the inverse distance ? The only reason given for this assump- 

 * Communicated by the Author. 



