460 
station Kodaikanal (height 2340 m.) in the South of British India 
with those at the base-station Peryakalam (290 m.) that the average 
temperature of the intermediate layer undergoes oscillations of about 
0,7° C., opposite to the simultaneous barometric changes at the base- 
station. The correlation factor between the two is r== 0,75. The 
station Kadaikanal evidently still lies in the stratum in which these 
temperature changes occur, for the temperature there changes in 
the same way as in the layer underneath. The correlation factor 
between the two temperature changes is 7 == 0,69. 
With an amplitude of the atmospheric oscillation of 0,6 mm. at 
sea-level and of the temperature oscillation of 0,7° C., the air-stratum 
in which both changes would be in harmony would lie at about 
1000 m. above the mountain station. The temperature changes are 
in this case restricted to the condensation level. 
The results of Exiot’s investigations ') would show that this is a 
general phenomenon. From a comparison of the barometric changes 
at the mountain stations in British India with those of the stations 
in the plains, he deduced that during the barometric maxima at 
sea-level, an abnormally large quantity of air is found below the 
level of the mountain siations and an abnormally small quantity 
during the minima. The temperature changes that determine the 
barometric pressure here occur in the lower 2000 tot 3000 metres 
in the region where the heat of condensation plays an important part. 
2. In the very lowest strata of the atmosphere the oscillation of 
the temperature is of a different nature. Over the whole of the area 
here considered the temperature of the stations in the plains follows 
namely very regularly tbe identical barometric change with a lag 
of about six months *). This oscillation of the temperature must have 
had a disturbing action on the observed barometric oscillation, since 
the phase differs by about a year (i.e. more than '/, period) from 
the value required for the formation of the barometric oscillation 
(see 1). Still no disturbance is observed and the curves representing 
„the barometric oscillation and these temperature changes generally 
show great similarity. This must probably be ascribed to the small 
thickness of this layer, which consequently has to be considered as 
a thin transition layer resting on the surface of the earth. 
The temperature oscillations mentioned sub 1 and 2 are in com- 
plete agreement with the following scheme of changes : 
If we suppose the general circulation of the air to be subjected 
to fluctuations in such a way that it is increased by the barometric 
1) Indian Metereological Memoirs VI, p. 102. 
. *) Cf. Metereol. Zeitschrift loc. cit. 
