278 Dr. J. CrolPs Remarks on 



for believing that the ratio of light to heat is incomparably 

 different in the two cases." This very argument from the 

 extreme smallness in the amount of light derived from the 

 stars in comparison to that from the sun, intended by him to 

 convince me of the absurdity of supposing that space pos- 

 sesses a temperature as high as — 239°, is just the argument 

 advanced by myself upwards of eighteen years ago, in the 

 1 Reader ' for December 9, 1865, and afterwards reproduced 

 in ' Climate and Time/ at page 39^ from which I quote the 

 following: — 



• We know that absolute zero is at least 493° below the melting- 

 point of ice. This is 222° below that of space. Consequently, if 

 the heat derived from the stars is able to maintain a temperature 

 of — 239°, or 222° of absolute temperature, then nearly as much 

 heat is derived from the stars as from the sun. But if so, why 

 do the stars give so much heat and so very little light ? If the 

 radiation from the stars could maintain a thermometer 222° above 

 absolute zero, then space must be far more transparent to heat- 

 rays than to light-rays, or else the stars give out a great amount of 

 heat, but very little light, neither of which suppositions is pro- 

 bably true. The probability is, I venture to presume, that the 

 temperature of space is not very much above absolute zero! 



In regard to Prof. Newcomb's objections to the reasons 

 which I have adduced to show that the ocean ought to be 

 warmer than the land, I am at a loss to understand how he 

 can have so completely misunderstood me on that point. I 

 thought I had expressed my views with sufficient clearness, 

 but now fear I cannot have dene so. I need not, however, 

 again go over my argument in detail, but shall simply state 

 what the views are which I have all along maintained. This 

 will suffice to show that these views are diametrically the 

 opposite of those which my critic has attributed to me. 



The temperature of a body can remain stationary only when 

 the rate at which it is losing equals that at which it is receiving 

 heat. If heat be lost more rapidly than it is received the 

 temperature will fall. The fall of temperature will diminish 

 the rate of loss till the rate of loss equals the rate of gain. 

 After this the temperature becomes stationary. If we have 

 two bodies, A and B, the same in every respect, each re- 

 ceiving (say from the sun) the same amount of heat in a given 

 time, and if the only difference between them be that A has a 

 greater difficulty than B in getting quit of the heat which it is 

 receiving, then, for the reason just assigned, A will necessarily 

 stand at a higher temperature than B. Let us now suppose 

 the southern, or water hemisphere, to be A, and the northern, 

 or land hemisphere, to be B. I have endeavoured to show 



