in his paper on the Problem of the Velocity of Sound. 101 



show how it could strike one corner of the equilateral triangle so 

 as to be heard at each of the other corners (where the observers 

 stood) in 2 seconds. Surely he will be able to see that it is a 

 mathematical impossibility that the flash should fall in any way 

 whatever so as to be heard by each of the two observers, accord- 

 ing to the common theory, in less than 1\ seconds. But it was 

 heard by each of them in 2 seconds. Here then is a proof that 

 the sound was transmitted in this case nearly four times as fast 

 as the common theory allows. And yet with this unanswer- 

 able fact before him, supported by other confirmatory observa- 

 tions by Prof. Montigny, Dr. Le Conte asserts that I have 

 " failed to produce a single unexceptionable fact, or a single satis- 

 factory observation, in verification of my theoretical deductions" 

 Such assertions as this are easily made, even in the presence of 

 plain evidence to the contrary ; but they should never be intro- 

 duced into inquiries after scientific truth. 



And again, with regard to Captain Parry's record of the word 

 " fire " having been heard after the report of the gun in his expe- 

 riments on sound. How does Dr. Le Conte dispose of that 

 fact ? There are persons now living who were present at the 

 experiment and noticed the fact. There was no room for doubt- 

 ful opinions. The fact is of such a nature that they could not 

 be mistaken. They testify that they distinctly heard the word 

 "fire-" after the sound of the gun's report had passed them. 

 But Dr. Le Conte gets rid of this well-authenticated fact in a 

 very simple and summary way, a way by which any other un- 

 pleasant fact may also be got rid of. He tells us that "the 

 records of the most trustworthy experimentalists concur in esta- 

 blishing the general fact that all sounds travel at the same rate" 

 Captain Parry's officers we see, then, were not trustworthy experi- 

 mentalists. But I deny the truth of the assertion made here by Dr. 

 Le Conte. For let it be remembered that the question at issue 

 is not whether all gentle sounds (i. e. sounds of the musical 

 type) travel at the same rate, but whether a violent sound travels 

 at the same rate as a musical sound ; and I deny that experi- 

 mentalists concur in establishing this to be a fact, as Dr. Le 

 Conte asserts they do. That all musical sounds travel at the 

 same rate has been most satisfactorily proved ; and this result 

 agrees accurately with my theory, and confirms it. But with 

 regard to the comparative velocities with which violent and gentle 

 sounds travel, any person who will turn to Sir J. HerschcPs 

 Table of experimental results, given in art. 16 of his ' Treatise 

 on Sound/ will find there abundant cause for suspecting that 

 the velocity of sound depends in some way on the mode of its 

 genesis. Captain Parry's fact still therefore stands an obstinate 

 witness with Prof. Montigny's facts in favour of the truth of my 



