20 DISCUSSIONS IN CLIMATOLOGY. 



The question of the temperature of space has been 

 investigated in different ways by Pouillet and Herschel ; 

 and the result arrived at was that space has a tempe- 

 rature of — 239° F., or an absolute temperature of 222°. 

 The mean absolute temperature of our earth is about 

 521°. Consequently according to these results, the 

 heat received from the stars is to that received from 

 the sun as 222 to 299. All my determinations of the 

 change of temperature due to changes in the sun's dis- 

 tance were computed on these data, although I believe, 

 for reasons stated, that space must have a much lower 

 temperature. Recent observations of Professor Langley 

 made during the Mount- Whitney expedition confirm 

 the correctness of my belief. 



Professor Newcomb, however, wholly ignores all 

 that has been done on that subject, for he commences 

 his review by the statement that "practically there is 

 but one source from which the surface of the earth 

 receives heat — the sun, since the quantity received 

 from all other sources is quite insignificant in com- 

 parison." 



He states that he regards the conclusion that the 

 temperature of space is —239° as having no sound 

 basis. This may be perfectly true ; but it is hardly a 

 warrant for affirming that practically there is but one 

 source (the sun) from which the surface of the earth 

 receives heat, without even referring to the researches 

 of these eminent physicists who have arrived at a 

 totally different conclusion. Any one who has read 

 'Climate and Time' will know that I adopted — 239° as 

 the temperature of space, not because I believed that 

 estimate to be correct, but because at the time I wrote 

 there was no other to adopt. In fact in adopting so 

 high a temperature for space I was doing my theory 

 a positive injury. This is obvious ; for the lower the 



