UPPER AIR—GOLD AND HARWOOD. 265 
The problem of the vertical distribution of temperature in cyclones 
and anticyclones depends for its solution on upper-air observations. 
Hann deduced from the temperatures at high-level observatories that 
cyclones were colder than anticyclones, the mean difference of tem- 
perature up to 3.5 kilometers being as much as 5° C. Grenander 
found similar results by a consideration of the kite and balloon ascents 
at Hald and Berlin, while Von Bezold deduced from the Berlin 
manned balloon ascents that the relative coldness of the cyclone was 
maintained even up to 8 kilometers. 
The results in the present report, obtained by taking only those 
cases in which the sea-level pressure exceeded 770 millimeters or was 
less than 750 millimeters, and correcting the observations for seasonal 
and local variations, showed that the cyclone was colder than the anti- 
cyclone up to 9 kilometers, while at greater heights the conditions 
were reversed, and the anticyclone became much colder than the 
cyclone; but the effect of the temperature difference in the lower 
layers on the pressure difference is so considerable that even at 14 
kilometers the pressure gradient is not reversed. In these circum- 
stances it 1s difficult to see how air can be brought into the anticyclonic 
and out of the cyclonic regions in the upper air. The cirrus observa- 
tions imply a definite outward motion over cyclonic regions, but a 
rotation in the same direction as at the surface, which can be the case 
only if the gradient of pressure is also in the same direction as at the 
surface. These results imply that there is motion across the isobars 
from the lower to the higher pressure. Now, although it is possible 
for such motion to exist if the velocity in the cyclonic region exceeds 
a certain value, or, in the anticyclonic region, lies between certain 
limits, it is not possible to have steady motion of this type, and the 
effect of damping would be to make the motion from the higher to 
the lower pressure. The evidence points to the conclusion either 
(1) that cyclones and anticyclones arriving in the European area 
are in general dissipating systems which are continually replaced by 
other systems arriving from what may be called productive regions, 
or (2) that there is interchange of air with regions in which the sur- 
face temperature or the temperature gradient differs sufficiently to 
produce mean temperatures greater in low-pressure areas and less in 
high-pressure areas than are found over Europe. 
It is interesting in connection with this part of the subject to note 
that Shaw and Lempfert deduced from a discussion of surface air 
currents that the central areas of anticyclones were not the regions of 
origin of currents, and could not, therefore, be places where descent 
of air was taking place to any considerable extent. The temperature 
observations in the first 3 kilometers agree with this conclusion, since 
they show that there is no approach to a regular adiabatic gradient 
near the centers of anticyclones, 
