274 MR. w. H. DINES ON THE VERTICAL TEMPERATURE 



irregularities, and different sectors of the cyclone would probably show systematic 

 variations, yet the distribution of temperature would certainly be in its main features 

 the same as that shown on the diagram. 



Using the same data, viz., the indication given by the temperature, we see that the 

 descending current of the anticyclone starts from a height of about 1 1 km. and also 

 spreads out as it descends ; it, too, forms part of a cone, but has the apex upwards. 

 Unlike the upward cyclonic current, its intensity slackens some distance before the 

 end of its course, neither does the current seem to be so pronounced, since the 

 departure only reaches +5 C. against -10 C. for the cyclone (29'06 in.). 



The nature of the circulation thus indicated agrees well with what is known from 

 other sources. The ascending current in the lower part of a cyclone can be inferred 

 with certainty from the inward tend of the surface winds ; it is also proved by the 

 formation of clouds and rain. That the region of ascending air increases with height 

 may be deduced from the fact that the formation of cirrus is often the first sign of an 

 advancing cyclone, and rain may fall from high clouds some time before the lower 

 cloud sheet and scud are formed. Also high clouds are generally visible after the 

 lower sheet has cleared when the depression is passing away. 



The descending current of the anticyclone is proved by the absence of high cloud 

 at the centre of an anticyclone, for no cloud can remain unevaporated in a descending 

 current, also by the great dryness that prevails at such times on mountain summits. 

 But the descending current does not reach the earth at the centre, for Messrs. SHAW 

 and LEMPFERT, in their ' Life-History of Surface Air Currents ' (M.0. 174, p. 24), state : 

 "These latter," i.e., the central areas of well-marked anticyclones near the ground, 

 " are for the most part inert and comparatively isolated masses of air, taking little 

 part in the circulation that goes on around them." Also, in England at all events, 

 an anticyclone is in the winter usually associated with a belt of low cloud, just above 

 which, as we know from kite and balloon ascents, there is nearly always a sharp 

 inversion of temperature. The descending current cannot reach the cloud, for if so 

 it would dissipate it at once, and there can be no mixing of air at the boundary, for 

 often just above the cloud the humidity is as low as 20 or 30 per cent. 



The question of the difference of temperature in the various segments of cyclones 

 and anticyclones has not been dealt with. In my opinion the number of observations 

 is nothing like sufficient to eliminate chance differences that would inevitably occur. 

 There seems to be no obvious correlation between the direction in which a balloon 

 travels and the temperature conditions, neither can I see that it makes any difference 

 if a cyclone is travelling quickly or slowly. The only point that I have noticed is that 

 there is a tendency for a higher temperature at the first few kilometres in the rainy 

 belt of south and south-easterly wind that lies in front of an advancing disturbance. 



t is not safe in meteorology to draw conclusions from a single instance, but the 

 following case may be of interest : On November 3rd, 1910, at 2.30 p.m., a balloon 

 was sent up at Pyrton Hill. The liaroineter, reduced to sea level, stood at 735 mm. 



