1825.] Velocity of Sound. 273 



perature of the centigrade scale, and dry air, give difFerences of 

 3-1^, whilst the observations of 27th and 28th of January, 'whe^ 

 shots were distinctly heard on both stations, h^fjp^te "^vidi^r-q 

 ence of ^-^g- from each other. n'^'*^ »,»4w \At>\\ ^c',-! 



The time which sound employs to travel from one statf6n ti^^ 

 another being duly ascertained, we proceeded to measure th^,^ 

 distance between both stations. The distances of the steeples^^ 

 of Utrecht and Amersfoort, Utrecht and Naarden, and Naam_j 

 den and Amersfoort being accurately known, we measured^ 

 angles on our stations between these steeples, and on eacli,^ 

 steeple between the other steeples and the stations. Thus the, 

 distance was calculated by four different triangles, and the| . 

 greatest difference between these calculations was 2"',45 of^ 

 eight feet, which appeared of no consequence in these experi- ' 

 ments. The distances of the different steeples which we took.? 

 for our basis, result froin tlies very exact geometrical, suryey of 

 General KrayenhofF.* . & 



From these different data we found, by calculations of which 

 the detail will be given hereafter, that in our experiments at.%. 

 temperature of 32^ Fahrenheit^ or 0° of the centigrade scale, th&2 

 velocity of sound is 332'",049, or 1089,7445 English feet perj 

 sexagesimal second. A table showing the comparison of our-^ 

 experiments, with the observations of other philosophers, is ' 

 also annexed to this paper. ^ .. 



Experiments on the Velocity of Sound on the 21th June, 1823^1'* 

 ^r^ -dj fO m- compared with Theory. '^ f - ^^ 



Having thus far stated the means by which the distance 

 between the stations of Kooltjesberg and Zevenboompjes was 

 ascertained, and the rate determined of the clocks by which the 

 velocity of sound was measured, I will now proceed to give the^ 

 experiments which were made on the 27th of June, and compar^^ 

 the result with theory. The following table contains the time] 

 which sound employed to travel over the basis on the 27th oj; 

 JiUne, when 22 shots were simultaneously fired, and equally" 

 s^en and heard on both stations. The first column of this table 

 shows the number of the shot, the second the time which soun^^ 

 employed to travel from Kooltjesberg to Zevenboompjes, 'a.^^. 

 observed on the latter station, and the third column the time',, 

 which sound employed to come from Zevenboompjes to KQoUf'„ 

 jesberg, also observed on the latter place. , [ *j,^m 



• Precis des Operations Geodesiques et Trigonometriques en Hollande, rparffc'j 

 General Krayenhoff. . , , ►. - -j(,jg-j 



■ r. -"'*■'-" '■■tit ,li wl'b.t>:>ui?fic^ «»w 



New Series, vol. x. ^V^^^^^^^^ "^^^ ^^^^'^ ^^^^ *^»^ 



