PORTION OF THE COSMOS. COSMICAL SPACE. 37 



ing to a widely prevalent opinion, the stars belonged to the 

 region of the fiery aether, but because they are themselves of 

 a fiery nature :{ 73 ) and Aristarchus, of Samos, even taught 

 that the fixed stars and the sun are of the same nature. In 

 very recent times, through the influence of the two great 

 French mathematicians who have just been named, the in- 

 terest of an approximate determination of the temperature of 

 space has been more strongly felt, as it has at length been 

 perceived how important, on account of the radiation of heat 

 from the earth's surface to the heavens, was this deter- 

 mination in respect to all thermic relations, and, one might 

 even say, to the habitability of our planet. According to 

 Fourier's analytical theory of heat, the temperature of space 

 (des espaces planetaires ou celestes) is somewhat below the 

 mean temperature of the Pole, or perhaps even somewhat 

 below the lowest temperature hitherto observed in the Polar 

 regions. Fourier estimates it accordingly at from 50 to 

 -60 Cent. (-58to-76Fah.) The point of greatest cold 

 (pole glacial) no more coincides with the pole of the earth 

 than does the "thermal equator" (which connects the warmest 

 points on all meridians) with the geographical equator. 

 Arago concluded the temperature of the north pole, from 

 the gradual decrease of mean temperatures, to be 25 Cent. 

 ( 13 F.) ; the maximum cold observed by Captain Back, 

 in January 1834, at Port Reliance (lat. 62 46'), was 

 56-6' C. (-69-88 P.) (? 4 ) The lowest known tempera- 

 ture is, I believe, that which Neveroff observed on the 21st 

 of January, 1838, at Jakutsk (lat. 62 2'). The accurate 

 Middendorff had compared the observer's instruments with 

 his own. Neveroff found the temperature on the day in 

 question, -60 Cent, (-76 P.) 



