S. Newcomb—Some points in Climatology. 23 
sun as 222 to 299. I wonder that he did not see in thisa 
reductio ad absurdum either of the results of Pouillet and 
Herschel, or the law of radiation which he assumes. Photo- 
metry shows that the combined light from all the stars visible 
in the most powerful telescope is not a millionth of that re- 
ceived from the sun, and there is no reason for believing that 
the ratio of light to heat is incomparably different in the two 
cases 
In considering the question of the heat conveyed by aerial 
currents Mr. Croll quotes from my former paper so fully and, 
fairly that I do not see any necessity to repeat my views at 
length. I can only say that while I now see more plainly than 
before some reason why a body at the upper region of the 
earth’s atmosphere should, on the average, be colder than at 
the surface, I do not see that we have data for fixing the fall of 
temperature at 5° or 100°. If the degree of cold is greater 
than that due to expansion, then Mr. Croll is right in main- 
taining that the aerial current would not carry to the poles all 
the heat with which it left the equator, but even granting this 
condition I see no ground for supposing the quantity of heat 
conveyed to be insignificant. 
shall now consider some of Mr. Croll’s reasons why the 
ocean should be warmer than the land. His assumed law that 
adduces, in support of his thesis, the fact that water is more 
transparent to the solar rays than the rays which it would itself 
radiate; and that the upper layers of water would act like the 
glass of a green house and thus allow the water to stand at a 
higher temperature than it would otherwise do. This addition 
to the modus operandi seems to me quite sound, and, therefore, 
to show one true cause why water might rise to a higher mean 
temperature than the land, though I am unable to say whether the 
increase would be measurable with an ordinary thermometer. 
But Lam sorry to find that, notwithstanding his addition of a 
Sound cause, he adheres to views so diametrically opposite to 
what I supposed to be the fundamental laws of thermodynamics 
that I feel compelled to state the case more fully. His first 
reason why the ocean should be warmer than the land, is in 
the following words: 
First.“ The ground stores up heat only by the slow process of 
conduction, whereas water, by the mobility of its particles and 
its transparency for heat-rays, especially those from the sun, be- 
comes heated to a considerable depth rapidly. The quant 
heat stored up in the ground is thus comparatively small, while 
the quantity stored up in the ocean is great. 
