400 1 he Theory of the Winds. 



than does the equator ; but the reverse holds good in the 

 winter, yet the winter as well as the summer temperature of 

 the stratosphere above the poles is higher than it is above 

 the equator. 



One suggestion * made was that the high temperature of 

 the stratosphere may be due to the presence in it of ions and 

 meteoric dust. But it is necessary to suppose that these are 

 most numerous in high latitudes. 



That ions exist in the upper atmosphere is now considered 

 to be very probable. Prof. H. Nagaoka suggests that they 

 may result from two causes. The first cause is the ultra- 

 violet light of the sun, which he believes is capable of 

 ionizing the atmosphere down to about 40 kilometres from 

 the earth's surface. The second is the stream of electrons 

 emitted by the sun. These electrons according to Arrhenius 

 would be caught by the earth's magnetic lines of force and 

 would be deflected in long spirals along the lines to the poles. 

 Some heating of the atmosphere may result from their loss 

 of velocity on reaching the atmosphere. They may also 

 arrest some of the sun's heat for the following reasons. 



At ordinary temperatures ions load themselves by attracting 

 surrounding molecules of gas. They thus form complexes 

 consisting of as many as thirty molecules. Such groups of 

 molecules may possibly arrest rays other than the ultra-violet 

 ones, and raise the temperature of the gas in which they move. 

 I am not aware, however, that any experiments have been 

 made to ascertain the effects, if any, ions have on radiant 

 heat. 



The variations which take place in the direction of the 

 flow of the winds from time to time seem to demand some 

 variable cause. Both the quantity of meteoric dust, and 

 the number of ions in the stratosphere, no doubt vary from 

 time to time. 



If ions can intercept the heat of the sun or warm the 

 atmosphere by impact as they reach it, and owing to the 

 magnetic field of the earth are deflected towards the poles, 

 the comparatively high temperature of the stratosphere over 

 high latitudes might be accounted for. 



Yours very truly, 



Abbeyfield, K. M. DEELEY. 



Salisbury Avenue, 

 Harpenden. 

 Feb. 15, 1916. 



* Ibid. p. 31. 



