186 
frequency, and throughout { will be used to mean the inter-nodal distance 
for the systems of standing waves. For a perfect gas the adiabatic equa- 
tion (pvk- —rcnstant) must be used, whence 
op __p @) 
ov T v 
Substituting this value in (1) 
v2pk 
V2 = —- = kpv = 4n??. (3) 
¥ 
Let equation (3) refer to the tube B, Fig. 1, in series I, which contains 
air, and is at 0° C., and let a similar equation with subscripts apply to the 
tube A in the steam bath. 
V?, =k, p, vy =4n?, A*,. (4) 
ky 
Dividing (4) by (3) and solving for the ratio 
ine CLO Taw (5) 
kas vy 
From Gay Lussac’s law specific volumes are directly proportional to 
absolute temperatures, whence 
kes oe (6) 
From (6) the results given in table I are calculated. 
For series II however, using nitrogen at liquid air temperature, the 
p-v-T relation to Bestelmeyer and Valentine was used, 
p v=0.27774 T—(0.03202—0.000253 7’) p (7) 
Substituting in the fundamental equation 
(ho), 
for constant temperature, as determined by differen- 
) 4 kp (9) 
JQ vt (h,—h, T) 
and substituting this in (1). 
op 
od 
the value of 
tiating (7), 
