350 W. Ferrel—Relation between the Barometric Gradient 
can only be determined from observation. If in (7) F’ vanishes, 
D, must vanish, and consequently by (9) 7 vanishes and the 
The g lue of F’ for th 
creases, in order to satisfy (7), and hence (9) in this case gives 7a 
constant for all velocities, so long as u can be neglected in com- 
parison with n sin / in (7), but near the center of the cyclone, 
face, as that of a prairie, this value is probably applicable to 
cyclones of all degrees of violence upon such surface, oe 
lowing mean values of 7, given in connection with the several 
stations in the following table, were deduced from a considerable 
number of observations taken indiscriminately by comparing 
the directions of the wind with that of the isobars, as given 
ne signal service of the several countries to which the stations 
ong: 
Scarborough, 4° 587 Thurso, 15° 4” Nottingham, 27° 44’ 
Brest, 1 25 ‘Holyhead, 18 4 Oxford, 29 12 
Scilly, 10 1 ‘Aberdeen, 21 3 Brussels, 29 57 
Yarmouth, 13 49 London, 21 7 Paris, 36 23 
Pembroke, 14 47 Greencastle, 22 1 Skudnesnaes, 41 17 
From these results Mr. Ley arrived at the following conclusions - 
I. The winds commonly incline from the districts of higher 
toward those of lower pressure. The collective mean for the 15 
LW; 
etapa exactly confirm the theory of ordinary cyclones, 
which requires, where there is friction, that there should be @ 
otion of the air below toward the center of the cyclone, as 
‘ 
- 
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