162 AIR MASS ANALYSIS 
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35 30 20 10 0 =| 
TEMPERATURE °C. 
Fic. 1. TEPHIGRAM OF THE AIRPLANE SOUNDING AT DETROIT, MICHIGAN, JUNE 
24, 1937, BEGUN AT 4:00 am., E. S. T. (Specific humidities entered beside 
the solid line of the sounding. The dotted line is the path of a particle rising 
from the surface after it attained the maximum temperature of that day. 
The broken line AB is a pseudo-adiabat, the significance of which is ex- 
plained in the text. Areas horizontally shaded represent positive energy 
while those shaded vertically indicate negative energy, which opposes 
convection.) 
TEMPERATURE °G. 
Fic. 2. TEPHIGRAM OF THE AIRPLANE SOUNDING AT SAN ANTONIO, TEXAS, JUNE 
27, 1937, 2.00 a.m. E. S. T. (For explanation see legend to Fig. 1.) 
