448 THE POPULAR SCIENCE MONTHLY 



The first break in this theory was also made by Professor Bigelow in 

 the cloud work of the international year, when it was shown that the 

 distribution of warm and cold masses in the anticyclone was not 

 symmetrical but asymmetrical. In the symmetrical theory the center 

 of motion coincides with the center of heat or center of cold; in the 

 asymmetrical theory the center of motion is located near the edge of 

 the warm and cold masses. The actual cyclone is warm on the one 

 side and cold on the other side of the center, and likewise the anti- 

 cyclone is cold on one side of it and warm on the other side of it. The 

 northerly cold current, therefore, has a cyclonic center on the east side 

 of it and an anticyclonic center on the west side of it, while the south- 

 erly warm current has an anticyclonic center on the east side of it and 

 a cyclonic center on the west side of it. These differences are also 

 fundamental. Ferrel treated the equation of motion by one solution, 

 quite similar to that which he applied to the general circulation of the 

 hemisphere, and he found the vortical torque for the cyclone clockwise 

 on the outer part, anticlockwise on the inner part, with complex lines 

 of flow connecting them. The theoretical difficulties are quite obvious 

 when we consider that such a vortex as Ferrel worked out is applicable 

 only to a fixed mass of air; for example, put a mass of water in a 

 cylindrical vessel and sprinkle sawdust in it so that the stream lines 

 can be followed by the eye. If now heat is applied to the center it will 

 boil along the stream lines indicated by Ferrel's vortex, and especially 

 so if the glass vessel is rotating on its axis. This would make our 

 cyclones storms in which the same mass of air is boiling over and over 

 again along these fixed lines, whereas we have shown that the cyclonic 

 circulation is simply built up by currents of air which are streaming 

 through it in a very irregular way, and, anticipating the conclusion 

 which we have reached in our research, it may be asserted that the 

 cyclone, besides being asymmetrical, conforms only loosely to any known 

 type of theoretical vortex. The German school of meteorologists also 

 discussed the symmetrical vortex, but by another mathematical process. 

 There are two other solutions of the second equation of motion, one 

 of which was assumed to apply to the outer part and the other to the 

 inner part of a cyclone. The solution for the outer part has no vertical 

 current, while the circulation for the inner has a vertical current, quite 

 like that in the vortical helix, such as may be illustrated by the ordinary 

 tornado tube. Many attempts were made to join the outer part and 

 inner part in a single set of equations, the results conforming very 

 loosely to the observed facts in nature regarding the velocity and 

 angular directions. It is not too much to say that neither of these 

 systems of solution will find more than a very small application in 

 practical meteorology. Ferrel discussed the three equations of motion, 

 one by one, giving certain practical inferences which he found more 



