1 30 ~ SECTION PHYSICS. 



the question was perfectly new to me, that I should have thought these 

 periods perfectly equal to one another. His Highness did not tell 

 me whether I had answered these questions rightly or not; but 

 in the evening, when he came up to see the experiments, he assured 

 me that in those which had already been made, and had been repeated 

 two evenings before with a large arquebuse from the Petraja, it had 

 been found to be actually the case that the rate of the lesser sound 

 was equal to that of the greater ; that the wind, which on the second 

 evening was blowing from the south-east, did not affect it in any way 

 whatever ; and that the difference in the direction of the discharge 

 made no variation in the rate of progress of the said sounds. Nor did 

 his Highness's demands end here, for before I had left him, in order 

 to ascend the terrace to make the observationSj he finally asked me 

 what I should think would be the rate of two sounds, the one made 

 at a distance of two miles and the other at double that distance ? I 

 answered that I had also had a great curiosity to satisfy myself 

 whether the motion of sound was in itself of a continually slackening 

 velocity, or whether it were equable, because if it were found to be 

 such, it seemed to me that more curious consequences might be 

 drawn from it, and which might prove to be of great use. Upon this 

 he urged me to say what I thought, as he wished afterwards to make 

 the experiment. I answered and indeed too boldly that at double 

 the distance the time would be exactly double, for I held that the 

 progress of sound was in itself uniform that is to say, that in any 

 given equal spaces of time it will traverse equal distances. As I had 

 reasoned on this particular point the day before, and I seemed to 

 have greater reason to be convinced of this than of the contrary, I 

 therefore threw no doubt in my answer, and for the time being our 

 conversation stopped there." 



Then after having related how the following day he had determined 

 the required distance between the Petraja and Florence, about 9500 

 braccia, he continues : " Whilst conversing with his Highness and 

 Prince Leopold about the experiments which had been made, and 

 others which were to be made upon the subject of sound, I took occa- 

 sion to let their Highnesses hear the contents of the enclosed writing, 

 in which I had, the previous evening, noted down, more for my own 

 remembrance than for any other purpose, all that had once suddenly 



