Emerson. | 18 [Feb. 17, 1871. 
theory of an independent atmosphere of vapor owing its suspension to 
heat alone, was established by Dalton, and is as incontestible as the 
theory of gravitation established by Newton. 
When watery vapor suspended in the air loses the amount of heat ne- 
cessary for its suspension, or, in other words, when the temperature is 
reduced to the ‘‘Dew-point,’’ vapor is immediately condensed into mist, 
dew, clouds and rain. Now there is good reasun to believe that the moon 
exerts no appreciable influence, directly or indirectly, upon the tempera- 
ture of our atmosphere. 
Some who have attempted to investigate this point by using reflectors 
and very delicate thermometers, have been led to the absurd conclusion 
that the moon’s rays emitted cold. The marked depression observed in 
the thermometers exposed to the lunar rays, was in no wise produced by 
these, but by radiation of heat from the instruments into a clear sky. 
In many parts of the surface of our globe, extensive regions exist in 
which it seldom or never rains, as in Lower Egypt. But in such places 
the atmosphere is very dry, and no local causes exist, such as mountains 
or hills, to interfere with the regular currents of the atmosphere and. 
favor the mixture of strata of different temperatures. Consequently, 
rain rarely falls. 
In other regions, in the Tropics, for example, there are extensive spaces 
in mid-ocean embracing many thousands of square miles, where the tem- 
peratures of the sea and atmosphere remain constantly within one or two: 
degrees of each other, with the atmosphere of vapor close upon the 
“Dew-point.’’? Here, if anywhere, the moon might be expected to pro- 
duce changes in the hygrometric conditions of the atmosphere. But for 
months continued, there is no rain or other proof of lunar influence upon 
the weather. It is only in the extra-tropical latitudes where many other 
active agencies exist to disturb the equilibrium of atmospheric tempera- 
ture, that the advocates of lunar influence assume to find evidence in fa- 
vor of their views. 
The power exercised by the moon upon bodies of water and permanent 
elastic gases on the surface of our planet, is solely derived from the law 
of gravitation, which exercises no influence, direct or indirect, in suspend- 
ing or condensing vaper, or controlling the conditions of weather as to 
wet or dry. These conditions are brought about solely through changes 
of temperature, during the operations of which the moon remains a silent 
spectator, taking no active part, so far as the condensation of vapor is 
eoncerned. 
Pending nominations 669, 670 were read. 
On motion of Mr. Winsor, the Library Committee were in- 
structed to report upon the subject of completing and pub- 
lishing the Catalogue of the Society’s books and pamphlets. 
And the meeting was adjourned. 
