85 
1913-14.] Principia Atmospherica. 
cause of any given distribution of pressure, with its attendant atmospheric 
motion ? ” 
We proceed, therefore, first to define in two lemmas the average con- 
dition of the atmosphere which we wish the reader to keep in mind, and 
secondly to apply the laws which have been already enunciated to make 
certain deductions or establish certain propositions with regard to the 
circulation of the atmosphere, which are set out in the synopsis. 
Section II. — Lemmas or Postulates. 
Lemma 1. 
In the stratosphere from 11 kilometres upwards it is colder in the 
high pressure than in the low pressure at the same level ; and in the 
troposphere, from 9 kilometres downwards to 1 kilometre, it is warmer 
in the high pressure than in the low pressure at the same level. 
Proof . — Table of average values of pressure and temperature at different levels over high 
pressure (1031 mb.) and low pressure (984 mb.) at the surface ; with pressure differences 
and temperature differences at each level. Compiled from the diagram and tables of 
W. H. Dines, F.R.S., in Geophysical Memoirs , No. 2, M.O. Publication, 2106. 
Table I. 
Pressure. 
Diff. 
Diff. 
Temperature. 
Low 
High 
A p 
A0 
Low 984 mb. High 1031 mb. 
K. 
mb. 
mb. 
mb. 
°A. 
°A. 
°A. 
15 
116 
123 
7 
14 
135 
146 
11 
- 
9 
224 
215 
13 
157 
171 
14 
- 
11 
226 
215 
12 
183 
201 
18 
- 
8 
225 
217 
11 
212 
235 
23 
- 
4 
225 
221 
10 
247 
273 
26 
+ 
1 
225 
226 
9 
288 
317 
29 
+ 
7 
226 
233 
8 
335 
366 
31 
+ 
13 
227 
240 
7 
388 
422 
34 
+ 
15 
232 
247 
6 
449 
483 
34 
+ 
14 
240 
254 
5 
516 
552 
36 
+ 
13 
248 
261 
4 
591 
628 
37 
+ 
12 
255 
267 
3 
675 
713 
38 
+ 
9 
263 
272 
2 
767 
807 
40 
+ 
8 
269 
277 
1 
870 
913 
43 
+ 
4 
275 
279 
0 
984 
1031 
47 
+ 
3 
279 
282 
Standard deviation of P 9 13 -8 mb. 
Standard deviation of P s 14T. 
Correlation coefficient between the variations of P 9 and P s from the means for the 
month (English ascents) ‘80. 
The table which is here given summarises the results of an important 
investigation by Mr Dines into the relation between the changes of pressure 
