71 
1918-19.] The Origin of Anticyclones and Depressions. 
sionally increased) in the region of origin, and more reduced in higher 
levels. The entropy is reduced slightly in lower levels, much reduced in 
the region of origin, but increased (owing to the descent of air from 
regions of higher entropy) in the upper regions. It will he seen that 
these results agree well with the figures given by Mr W. H. Dines for the 
average values of temperature, pressure, and density at various heights 
in areas of high and low pressure. I have calculated the entropy by 
equation (5) from the temperature and pressure, the quantities directly 
observed. The entropy is for one grm. of air, the zero being taken .as the 
entropy at a pressure of one dyne per square centimetre and a temperature 
of one degree absolute. 
Table of Average Values of Temperature, Pressure, and Density of Air in 
Regions of High Pressure and Low .Pressure. 
(Figures for temperature, pressure, and density from a paper by Mr W. H. Dines, F.R.S., 
in Trans. Roy. Soc ., vol. ccxi, p. 262, and article “Density” in Met. Gloss. M.O . , 225, ii.) 
H 
High Pressure. 
Low Pressure. 
Press. 
Tern. 
Dens. 
E. 
Press. 
Tern. 
Dens. 
E. 
Km. 
Dy/Cm 2 
°A 
Gm/Cm 3 
Jo/°A 
Dy/Cm 2 
°A. 
Gm/Cm 2 
Jo/°A 
10 
273000 
226 
•000421 
1-78 
247000 
225 
•000382 
1-80 
8 
366 
240 
531 
1*75 
335 
227 
514 
1-72 
6 
483 
254 
662 
1-73 
449 
240 
652 
1-69 
4 
628 
267 
818 
1*73 
591 
255 
807 
1-67 
2 
807 
277 
1012 
1-66 
767 
269 
992 
1-65 
0 
1031 
282 
1270 
1-61 
984 
279 
1226 
1 61 
Difference between High and Low. 
Ht. 
Press. 
Temp. 
Density. 
Entropy. 
10 
26 
1 
39 
-•02 
8 
31 
13 
17 
+ •03 
6 
34 
14 ' 
10 
+ •04 
4 
37 
12 
11 
+ •06 
2 
40 
8 
20 
+ •01 
0 
47 
3 
44 
•00 
It would appear that the average height of origin is about 4 to 6 kilo- 
metres, and it is interesting to note that in the anticyclone at this height 
the isentropic condition is practically attained. According to the ortho- 
dox convection theory it is in the cyclone that such conditions should 
appear. 
Mr Dines has attempted to verify the presence of ascending currents 
in an area of low barometric pressure and has found them to be of the 
