10 Prof. J. Lc Conte on the Discrepancy between the Computed 



Vary from to ^v, are inaudible to human ears, and are con- 

 sequently removed from the province of the experimentalist. 

 The two remaining classes of sound-waves, embracing velocities 

 ranging from ]jV to infinity, or from 166*2 metres (545 '3 feet) 

 per second to infinity, are, according to the author, within the 

 limits of experimental verification. It might be supposed that 

 we have here a variation of velocity abundantly sufficient to test 

 the truth of the theoretical results by means of the most casual 

 observations. But we are told that, by a legitimate interpreta- 

 tion of the analytical formulae, all musical sounds audible to men 

 are transmitted with sensibly the same velocity — that all ordinary 

 sounds belong to the same type, and that in both of these cases the 

 velocity does not differ sensibly from that admitted by philosophers. 



Nevertheless the author admits that, "if the theory here 

 advanced be true, the report of fire-arms should travel faster 

 than the human voice, and the crash of thunder faster than the 

 report of a cannon." With regard to musical sounds, we have 

 the most satisfactory evidence that sounds of every pitch and 

 violence are transmitted with precisely the same velocity. The 

 experiments of MM. Biot, Bouvard, Malus, and Martin prove 

 conclusively that the harmony of musical notes was not in the 

 slightest degree deranged by transmission through the air con- 

 tained in a pipe 951*25 metres (3120*96 feet) long*. Mr. W. H. 

 Besant mentions an experiment involving a severer test of the 

 truth of this, inasmuch as the distance was much greater. " On a 

 fine and still evening of June 1858, the Messiah was performed 

 in a tent, and the Hallelujah Chorus was distinctly heard, without 

 loss of harmony, at a distance of two English miles "f. As it is well 

 known that the human ear appreciates, with the greatest nicety, 

 the slightest differences in musical intervals, these facts may be 

 considered as establishing the absolute constancy of the velocity 

 of all aerial sound-waves embraced within the musical scale. 



Inasmuch as the range in the violence of the genesis (upon 

 which the variation in the velocity is assumed to depend) of 

 musical sound-waves may not be considered sufficiently extended 

 to afford a satisfactory test of this question, it may be interesting 

 to investigate the evidence derived from other kinds of sound. 

 Mr. Earnshaw thinks that there is sufficient reason to believe 

 that it is a fact that violent sounds are transmitted faster than 

 gentle ones. At the Meeting of the British Association at Leeds 

 in 1858, he was able to bring forward but a single fact which 

 seemed to support his theoretical deduction • viz., that during 

 one of Parry's voyages to the north, having occasion to make 



* Mem. d'Arcueil, vol. ii. p. 422. 



t Treatise on Hydrostatics and Hydrodynamics. Foot note at page 



