218 
BIGELOW. 
tion vanishes, and stream lines continuous within the same 
mass of liquid; the German vortex has no outer boundary, 
but a circumscribed inner region with vertical velocity 
increasing as the height, an outer region with no vertical 
component, and a maximum velocity at the separation of 
these two regions. One may frequently observe the German 
vortex in snow or dust whirls, when the currents of air are 
sharply deflected by walls and adjacent buildings. It is 
necessary, therefore, also to exclude the German vortex from 
modern meteorology, and this removes another large chapter 
from its literature. Fortunately, the treatment of the tornado 
vortices has been substantially correct, but meteorology must 
make a fresh start with the theory of cyclones and anti¬ 
cyclones. A series of suggestions can be found on this 
subject in my recent reports as to the kind of work required; 
but the task is one of great difficulty, and it may require 
much labor to finish it. 
THE GENERAL CYCLONE. 
The history of the theory of the general cyclone is very 
similar to that of the local cyclone. There exist two great 
analytic discussions, Ferret’s and Oberbeck’s, and, while they 
have much in common, the results partially contradict each 
other and they are only in partial agreement with the obser¬ 
vations. In the case of the general circulation the analysis 
and the observed conditions harmonize better than in that 
of the local cyclone, and it is therefore necessary simply to 
improve the details of the analysis, although the general 
circulation is really not so simple as is called for by that 
theory. To illustrate briefly, Ferrel derives a very powerful 
eastward movement at the poles and a vanishing motion at 
the equator, while Oberbeck reverses this conclusion. Ferrel 
and Oberbeck make a powerful northward component in the 
upper strata of the atmosphere and a strong southward com¬ 
ponent at the ground; but observations show that a very 
feeble poleward component is flowing in the upper air, and 
that in the lower air a series of irregular currents pass each 
