552 TL AG GLLANMIBIETALETN, 
vapor a vacillating factor subject to the control of any other 
agency which increases or decreases the atmospheric temperature. 
Whenever therefore an increase of carbon dioxide raises the 
temperature, it increases the quantity of water vapor and this by 
its thermal absorption further increases the temperature and 
calls forth more vapor and this action and reaction continue in 
diminishing force until an equilibrium is established. A decrease 
in carbon dioxide decreases the temperature and thus lessens the 
water vapor, and this further lowers the temperature and inaugu- 
rates a reversed series of actions and reactions. Fluctuation in 
the quantity of carbon dioxide therefore is attended not simply 
by its own individual effects, but by these auxiliary effects also. 
The carbon dioxide becomes therefore the determinative factor, 
and the question of the thermal absorption of the atmosphere 
may be discussed for convenience as though it were solely 
dependent upon the fluctuations in the content of this con- 
stituent, although this will not be strictly exhaustive. 
6. A second effect of increase and decrease in the amount 
of atmospheric carbon dioxide is the equalization, on the one 
hand, of surface temperatures, or their differentiation on the 
other. The temperature of the surface of the earth varies with 
latitude, altitude, the distribution of land and water, day and night, 
the seasons, and some other elements that may here be neglected. 
It is postulated that an increase in the thermal absorption of the 
atmosphere egualizes the temperature, and tends to eliminate the 
variations attendant on these contingencies. Conversely, a 
reduction of thermal atmospheric absorption tends to zntenszfy all 
of these variations. A secondary effect of intensification of 
differences of temperature is an increase of atmospheric move- 
ments in the effort to restore equilibrium. Increased atmos- 
pheric movements, which are necessarily convectional, carry 
the warmer air to the surface of the atmosphere, and facilitate 
the discharge of the heat and thus intensify the primary effect. 
In the case of a naked earth, the radiant energy of the sun fall- 
ing directly upon the tropical belt is concentrated in space, and 
subject to the minimum reflection; in high latitudes, the rays 
