212 
DR. SIMONS ON THE COEFFICIENT OF THE FORMULA 
Now, if the intensity of the gravitating force at Paris be g', whilst it is g at 
the place where the experiments are made, we have the weight of a cube centi- 
metre of dry atmospheric air, under a pressure of 760mm, and at zero Centi- 
grade, 0.001299541 
Under the same circumstances the ratio of the density of air to that of mer- 
cury, will be : 
0.001299541 g 1 g 
D “13.596152 ' g 1 10462.273 ’ g 1 ‘ 
If the barometric pressure becomes p, the temperature t Centigrade, the 
tension of aqueous vapor T, the density of the air becomes 
i y P~ f T g_ 
~ 10462.273 x 0.760 {1 + 0.00375./} g 
substituting this value of D in the formula of the velocity of Sound, and ob- 
serving that g = gj • -|j we have, 
or, 
V = 
V = 
\J 10462.273 x 0.760 {1 + 0.00375. /. )p .g' .-§~ 
e 3 rp v 8 ^ 
{p- £T} • 1G 
\J 10462.273 x 0.760 (1 + 0.00375. X 
\J K. 
\/ K. 
This formula shows that V is independent of the latitude ; and thus that 
the velocity of sound is not directly affected by the geographical position of 
the place of observation. From the late M. Borda’s pendulum experiments, 
we have the intensity of gravity at Paris, g 1 = 9.8282/. 
From MM. Gay-Lussac and Welter’s experiments, the value of K is 
deduced K = 1.3748. 
From the more recent investigations of M. Dulong, we have K = 1.421. 
Thus, taking K from MM. Gay-Lussac and Welter, the velocity of 
sound is 
V == 9.82827 x 10462.273 x 0.760 (1 + 0.00375./.}-^-^^ X \J 1.3748 
and taking K from M. Dulong, 
V = y/ 9.82827 x 10642.273 x 0.760 (1 + 0.00375./.} - ^ X y/ 
1.421 
