1913-14.] Principia Atmospherica. 101 
I have used this method for the calculation of the distribution of 
pressure and temperature in the cases represented by photographs of models 
in Mr C. J. P. Cave’s book on the Structure of the Atmosphere in Clear 
Weather * which includes that given in detail on p. 100. Some of the 
results are given below — the problem being understood to be stated thus : 
Given the wind-velocity at any point, to find co-ordinates for drawing the 
isobar for the next higher millibar and the isotherm for the next higher 
degree of temperature. It will be remembered that the isobar over the 
point of observation itself is to be taken parallel to the wind direction in 
accordance with Law 1, and the direction of the isothermal lines will be 
taken parallel to the line joining the computed co-ordinates, so that the 
distribution of pressure and temperature is to be represented each by two 
parallel lines, the co-ordinates giving their direction and their distance apart. 
1. Sounding of May 5, 1909, 6h. 43m. p.m. 
“ Solid Current ” ; Wind approximately uniform in direction and velocity 
from 2 kilometres to 10 kilometres. 
Table V. 
Height. 
Distance of next higher 
isobar in kilometres. 
| 
Distance of next higher 
isotherm in kilometres. 
k. 
k. 
k. 
k. 
k. 
9-10 
143 N 
233 E 
93 N 
93 W 
8-9 
143 N 
181 E 
1000 N 
1250 E 
7-8 
123 N 
291 E 
454 S 
54 E 
6-7 
114 N 
292 E 
137 N 
74 W 
5-6 
99 N 
141 E 
100 S 
139 W 
4-5 
77 N 
110 E 
832 N 
58 E 
3-4 
67 N 
187 E 
303 S 
909 W 
2-3 
. 58 N 
144 E 
769 N 
196 W 
1-2 
54 1ST 
353 E 
270 N 
49 E 
0-1 
In this case it is interesting first to notice the gradual separation of the 
isobars with increasing height and consequently diminishing density. This 
is the ordinary condition for the velocity remaining invariable with height. 
Secondly, it is noteworthy that the separation of the isotherms is 
generally large and also very irregular, showing approximate equality of 
temperature in any layer, but great want of conformity between one 
layer and another. Such variations in the distribution of temperature may 
easily be accounted for by local convection producing changes of tempera- 
ture and possibly clouds, and it leads us to reflect that the convection 
* Cambridge University Press, 1912. 
