ON THE GENETIC VIEW OF NATURE. 357 



first theoretical and experimental essays, experiments had 

 already been made by Sir Joliii Herschel at the Cape, 

 and independently by PouilluL in France, with the object 

 of incasurinL!; the annual expenditure of heat by the 49. 



",„,., .1 Til.- heat of 



sun. They had found it to be an enormous quantity, tii.hun. 

 Tliey represented it popularly by the thickness of a crust 

 of ice on the surface of the earth, which the heat radiated 

 annually by the sun would be able to melt, and they 

 frtund this to be about -SO metres or 100 feet. Mayer 

 was the th'st who seems to have put the question 

 ilefinitely : How is this enormous expenditure of heat 

 defrayed, which would, if not in some way compensated, 

 have residted, even in historical times, in a great lower- 

 ing of the temperature of the sun, and hence also of that 

 on the surface of our globe, such as is contradicted by all 

 historical evidence ? The answer which j\Iayer gave to 

 this question was based upon an application of his con- 

 ception of the equivalence of heat and the energy of 

 mechanical motion. As the sun, according to the cos- 

 nioLronic liypothesis " of Laplace, was originally formed by 



' These measurements were made ' si(l(5raiit le grand nombre que 



in 1837, and very nearly agreed. nous voyons, comme bolides ou 



The resulting figures Ci\n, of course, otoiles tombantes, uous ne pouvons 



only be considered as rough ap- pas doubter qu'a tout moment des 



proximations : they have been con- myriades d'astoroides semblables a 



siderably increased bj' more recent une grele epaisse se jettent dans 



observations. See A. Berry, ' A j tous les sens sur le soleil ou ils 



Short History of Astronomy,' p. perdent la force vive de leur mouve- 



397. I raent" (Mayer's ' Schriften und 



- It does not appear that Mayer I Briefe,' p. 264) ; and M. Faye re- 



brfiught his " meteoric" hypothesis marks that the fact that Mayer's 



of the generation and maintenance ideas are opposed to Laplace's theory 



of the heat of the sun into conncc- ] of the origin of the solar system 



tion with the nebular hypothesis of j explains how it came about that 



Kant and Laplace. In fact, in hi.s ' his theories were never reported on 



first mention of it in his com- or explicitly mentioned. Leverrier 



munication to the Paris Academy also seems to have ridiculed the 



in 1810 he says simply: "En con- ' meteoric hypothesis, according to 



