Xll NOTES. 



( 71 ) p. 36. Fourier, Theorie analytique de la Chaleur, 1822, p. ix. 

 (Annales de Chimie et de Physique, T. iii. 1816, p. 350 ; T. iv. 1817, p. 128 ; 

 T. vi. 1817, p. 259 ; T. xiii. 1820, p. 418.) Numerical estimations of the 

 loss which the heat of the stars (chaleur stellaire) suffers in passing through 

 space, by absorption in the ether, are attempted by Poisson, in his Theorie 

 mathematique de la Chaleur, 196, p. 436; 200, p. 447 ; and 228, p. 521. 



( 72 ) p. 36. On the warming power of the stars, see Aristot. Meteor, i. 3, 

 p. 340, lin. 28 ; and Seneca, on the height of the strata of the atmosphere 

 which have the minimum of heat, in Nat, Qusest. ii. 10 "superiora enim 

 aeris calorem vicinorum siderum seutiunt " 



P) p. 36. Piut. de plac. Philos. ii. 13. 



( 74 ) p. 37. Arago sur la temperature du Pole et des espaces celestes, 

 in the Annuau-e du Bureau des Long, pour 1825, p. 189, and pour 1834, 

 p. 192 ; Saigey, Physique du Globe, 1832, p. 60 78. From discussions on 

 the refraction of rays, Svanberg finds, for the temperature of space, 50.3 

 Cent., or -58.5 F. (Berzelius, Jahresbericht fiir 1830, S. 54) ; Arago makes 

 it, from polar observations, -56.7 Cent. (-70 F.) ; Peclet, -60 Cent. 

 ( ?6 F.) ; Saigey, by the diminution of heat in the atmosphere from 367 

 of my determinations in the Andes and in Mexico, 65 Cent. ( 85 F.), and 

 by thermometric observations on Mont Blanc and in Gay-Lussac's aerostatic 

 voyage, -77 Cent. (-106.6 F.) ; Sir John Herschel (Edinburgh Review, 

 Vol. Ixxxvii. 1848, p. 223) makes it- 132 F. That Poisson, (the mean tempe- 

 rature of Melville Island, lat. 74 47', being already - 18.7 Cent.or 1.7 F.), 

 could deduce for the temperature of space, from purely theoretical grounds 

 [according to which space would be warmer than the extreme limit of the 

 atmosphere ( 227, p. 520)] a temperature no lower than - 13 or + 8.6 F., 

 while, on the other hand, Pouillet (Comptes rendus de 1'Acad. des Sc.T. vii. 

 1838, p. 25-65) makes it 142 C. (223.6 F), must excite our astonish- 

 ment, and diminish our confidence in the methods of inquiry hitherto pursued 

 in these interesting speculations. 



(~ 5 ) p. 38. Poisson, Theorie mathem. de la Chaleur, p. 438. According 

 to him, the consolidation of the terrestrial strata oegan from the centre, and 

 proceeded gradually from, thence to the surface ( 193, p. 429). Compare 

 also Kosmos, Bd. i. S. 184 (English edition, Vol. i. p. 166). 



( 76 ) p. 38. Kosmos, Bd. i. S. 86 and 149 (English edition, Vol. i. p. 74 

 and 133). 



( 77 ) p. 39. " Were there no atmosphere, a thermometer, freely exposed 

 (at sunset) to the heating influence of the earth's radiation, and the cooling 



