CIRCULATION OF THE ATMOSPHERE 447 



all levels. The first theory can be illustrated by sliding the fingers of 

 the smooth hands over each other in opposite directions, while the 

 second theory can be illustrated by sliding the fingers between one 

 another on the same level; the fingers of the one hand will represent 

 the warm currents and the fingers of the other hand the cold currents. 

 This new view is really revolutionary because it renders inapplicable 

 the integrations which were attempted by previous authors. Unfor- 

 tunately the problem has become in this way so very complicated, that 

 no one of sufficient ability has yet been found to carry out the neces- 

 sary mathematical analysis with anything like fullness or precision. 

 At present meteorologists are engaged, by means of balloon and kite 

 ascensions, in determining the nature of the currents from the south 

 and from the north which prevail in different localities. Europe has 

 already done a great deal of work in this direction, and the United 

 States has recently made a beginning. A few soundings have also been 

 made over the Atlantic Ocean. Generally speaking, however, this is a 

 great field of research which it will require much money and time to 

 adequately complete. The circulation of the atmosphere, therefore, is 

 a great and fascinating problem for future development, and indeed 

 it may require more than one generation of scientists to bring it into 

 subjection. 



We have described the cold and warm currents as interpenetrating 

 on the same levels like the fingers of the two opposite hands. Gravi- 

 tation takes these warm and cold masses and seeks to make them inter- 

 penetrate yet more intimately, so that the warm masses will become 

 more cooled, and the cold masses more warmed, and the isobars and 

 isotherms coincide with each other and the gravity levels. It is a 

 curious fact that masses of warm and cold air having any size are 

 exceedingly reluctant to mix with one another; that is to say, the 

 interchange of heat is a molecular process which naturally goes on 

 slowly, and in accomplishing it, in the atmosphere, a great deal of 

 energy must be expended. The great masses are first torn into shreds 

 along their edges, and are gradually fritted away in the local cyclonic 

 circulation. The energy that is felt in storms of any kind is merely 

 an illustration of this thermodynamic process of interchanging tem- 

 perature. 



The Local Circulations 



Historically speaking, the year 1896-7 marks the beginning of a 

 period of transition in the history of local as well as general theoretical 

 meteorology. There have been two schools of meteorology : one Amer- 

 ican, whose head is Ferrel, and one German, of which Guldberg and 

 Mohn, Sprung, Oberbeck, Margules and Pockels are leaders. These 

 two schools agreed in one particular, namely, in that they assumed that 

 the cyclonic and anticyclonic circulations are symmetrical about a center. 



