POPULAR SCIENCE REVIEW. 
THE HEAT OF THE MOON. 
By J. CARPENTER, F.R.A.S., 
Of the [Royal' Observatory, Greenwich. 
[PLATE LIV.] 
O UT of the doubt that has so long shrouded the question of 
lunar calorescence, a small gleam of certain light is now 
appearing, and meteorologists, however reticent they may have 
hitherto been upon the point, must henceforth, in justice, credit 
the moon with some influence, feeble though it be, upon the 
thermic conditions of our atmosphere. Unless the lunar globe 
be composed of materials vastly different from those that form the 
earth — and we are not justified in supposing such a diversity— 
it must receive heat from the sun, and its surface must be raised 
in temperature as the earth’s is : it must obviously be warmer 
than space ; the heat it receives it must part with by reflexion 
and radiation, and we must receive our portion thereof. As the 
phase of illumination varies, as the sphere subjected to insola- 
tion turns towards us more or less of its heated surface, so, we 
may conclude, must the warmth shed upon us vary in degree ; 
and it is inferable that greatest effect should be felt at the time 
of full moon, and the least at the period of new. This was the idea 
entertained by Toaldo, who was doubtless the first who tabulated 
thermometric observations having any pretensions to accuracy, 
with the view of detecting variations depending upon or related 
to lunar positions. He summed up a series of thermometer 
readings extending over forty years, dividing them into two 
sections— the one including fourteen days about full moon, the 
other, fourteen days about the epoch of new moon ; and it re- 
sulted that the mean temperature of the full-moon semi-lunation 
exceeded that of the new-moon semi-lunation by about the 
twelfth part of a degree.* 
* “ Toaldo, Essai m6t6orologique,” etc. French edition. Chamb&w, 17S4, 
p. 77. 
VOL. IX. — NO. XXXIV. L 
