-1859] WRITINGS OF JOSEPH HENRY. 263 



weight as we descend ; the aqueous atmosphere surrounding 

 the whole earth would thus be found increasing in density 

 as we approach toward the liquid surface. If the tempera- 

 ture of the earth and of the space around it were 60° F. it will 

 be seen by table A, (p. 217,) that the pressure of this aqueous 

 atmosphere at the surface of the earth would be equal to half 

 an inch of mercury; if the temperature were 100° it would 

 be equal to 2 inches. This pressure however would be 

 sufficient to prevent any further evaporation, unless, as 

 we have said, an increase of temperature took place. 



In order that such an atmosphere should be in equilibrium 

 it would be necessary that the absolute amount of heat in 

 €qual weights and at different heights should be the same; or 

 in other words it should follow the same law as that of a 

 gaseous atmosphere. There would however be this great 

 difference between the two atmospheres, the one would be 

 readily condensed by a diminution of temperature beyond 

 a certain point into water, while the other would remain a 

 permanently elastic fluid at all temperatures. If therefore 

 the space beyond the atmosphere were colder than that 

 which would be due to the diminution which would natur- 

 ally take place in an aqueous atmosphere, a continual rain 

 would be the result, the moisture would be constantly evapo- 

 rated from the surface of the earth, and constantly condensed 

 by the cold above. Now were it not for the gaseous atmos- 

 phere which surrounds the earth and offers a resistance to 

 the ascent of the aqueous particles, we think such a condition 

 would actually exist. We are inclined to this belief from 

 the facts which have been stated indicating an exceedingly 

 low temperature to the space beyond our atmosphere. 



Be this as it may however, an atmosphere of this kind 

 would be exceedingly unstable, and if any portion of the 

 earth's surface were colder than another there would be a 

 constant condensation at the coldest parts, and a constant 

 evaporation at the warmest to restore the equilibrium. If 

 for example the heat of the equatorial regions were 80°, and 

 that of the polar regions at zero, the elastic force of the vapor 

 at the former place would be 1 inch, while at the latter it 



