OF GEOLOGICAL DYNAMICS. 97 



fessor Huxley will " Hansardize " me by looking to 

 my original paper on " The Mechanical Energies of 

 the Solar System," he will see that my contribu- 

 tion to the meteoric theory of solar heat was to 

 prove the insufficiency of any chemical theory, and 

 to point out that meteoric supply cannot be perennial 

 in even approximate uniformity with the existing 

 order of things^ I think he will find nothing in 

 that paper which " justly entitles " him to " disre- 

 gard " my present estimates, but, on the contrary, 

 much to enforce them. In a note to that paper, 

 dated May 4th, 1854, is to be found an indication 

 of my subsequent correction of the untenable part 

 of my first views, and, obstructing it, a difficulty 

 which 1 then felt as to the sun's capacity for heat. 

 In my article on the "Age of the Sun's Heat," 2 to 

 which Professor Huxley refers, a resolution of that 

 difficulty is pointed out, according to which it is 

 shown that the sun's capacity for heat is probably 

 more than ten times, and less than 10,000 times 



1 Farther information on this point is to be found in an extract 

 from the Proceedings of the Glasgow Philosophical Society, March 

 24, 1859, appended (Part III., below, p. 127). 



2 Macmillarfs Magazine, March, 1862. 



VOL. II H 



