eS EE LE oe 
and the Velocity of the Wind. 345 
In a perfect cyclone the isobars are circular and 7 becomes 
the radius of the circle, and in this case the gradients are esti- 
mated in the direction of the radius from the center. In the 
two ! soma hemispherical cyclones the gradients are estimated in 
irection of the meridians, and the isobars, supposing the 
cyclones to be perfect and unaffected by local disturbing 
causes, correspond with the parallels of latitude. In this case 
rin (2) is the distance from the earth’s axis, and v cos? ex- 
presses the component of motion relative to the earth’s surface 
rise to considerable error. And if the distance from the center 
from carrying out more in detail principles which the writer 
has already had published at different times and places, but a 
complete demonstration of the law would be too complex and. 
