184 ON THE GENERAL CIRCULATION OF THE ATMOSPHERE. 
task of conveying the excessive heat of the air strata adjacent to the 
ground in the torrid zone continuously to the entire atmosphere at all 
altitudes and latitudes, and thereby restoring, by a progressive circu- 
lation, the neutral equilibrium disturbed in the torrid zone. 
If—with aconsideration of the circumstance that the path of these cur- 
rents can not intersect, and of the further circumstance that the veloc- 
ity of the uprising currents must increase with the height in a ratio 
inversely proportional to the air pressure there prevailing, and finally 
of the circumstance that the air must retain unchanged the velocity 
it has once received, until it is destroyed by friction, mixture, or the 
work of compression,—one attempts to construct the possible paths of 
these currents, then he will necessarily arrive at the wind system as- 
sumed by me, which rests essentially upon the inertia of the overheated 
air set in accelerated motion by the equatorial updraft. This inertia 
not only drives the accelerated air in the higher air regions toward the 
poles, but it is also the cause of its return in the lower strata to the 
equator. 
It would lead me beyond the limited scope of this memoir were I to 
enter upon a more extended investigation of the inertia effeets of this 
mass of air, or upon the partly modifying influence of aqueous vapor. 
But permit me to add a few words upon the development of the 
great local accumulations of energy which find expression in maxima 
and minima of air pressure. The total air pressure over all parts of 
the earth must be constant, since this integral represents the unchang- 
ing weight of the total mass of air. A local diminution of pressure 
must therefore be accompanied by an increase of pressure at other 
places. It is manifestly fruitless to seek the cause of areas of high 
and low pressure in the local condition of the atmosphere. These areas 
are frequently announced by the barometer long before any change in 
the condition of the atmosphere at the earth’s surface has occurred. 
Only light streaks of cloud are frequently wont to betoken a change 
originating in the higher regions of the atmosphere. 
In my memoir, ** Upon the conservation of energy in the earth’s 
atmosphere,” I have already removed the place of origination of areas 
of high and low pressure to the higher regions of the atmosphere. 
In these areas continuous changes of temperature and velocity take 
place which are derived from the place of up-rush of the air,—that is, 
from their previous temperature and humidity. If no change of sea- 
sons took place, probably a greater regularity would prevail in the 
upper currents of the air, which then would also give weather rela- 
tions a definite sequence; such a sequence, up to the present time, 
has not been detected. We can not judge from what region the air 
comes which at any point of the earth’s surface momentarily flows 
poleward at higher elevations. The temperature and velocity which 
this air has depends on the place of up-rush and on the season of the 
year. Now since the consumption of heat in the up-rising of the air, 
