FACTORS INFLUENCING TRANSMISSION 369 
TaBiy 2 
O10 SO On eo 
ments contain temperature and humidity measuring 
elements that are relatively free of lag; they are 
attached to airplanes or dirigibles or they are carried 
aloft by means, of captive balloons or kites. The 
above tables are for use in connection with such 
measurements. 
M 
w 
r.h. 
t(CF) 
— 4.0 
—1 0/4 
+ 3.2 
+ 6.8 
+10.4 
+14.0 
+17.6 
Two main cases must be distinguished. First, the 
refractive index or M is very nearly a linear function 
of the height in the lower layers (at heights above 
about 500 to 800 meters the variation of refractive 
index with height will deviate from linearity only in 
very exceptional instances). This is the standard 
