52 FRAGMENTS OF SCIENCE 



source of life, nine out of ten of those who are alarmed 

 by the form which this assertion has latterly assumed 

 would have assented, in a general way, to its correctness. 

 Their assent, however, was more poetic than scientific, 

 and they were by no means prepared to see a rigid me- 

 chanical signification attached to their words. This, how- 

 ever, is the peculiarity of modern conclusions — that there 

 is no creative energy whatever in the vegetable or animal 

 organism, but that all the power which we obtain from 

 the muscles of man and animals, as much as that which 

 we develop by the combustion of wood or coal, has been 

 produced at the sun's expense. The sun is so much the 

 colder that we may have our fires; he is also so much 

 the colder that we may have our horse-racing and Alpine 

 climbing. It is, for example, certain that the sun has 

 been chilled to an extent capable of being accurately ex- 

 pressed in numbers, in order to furnish the power which 

 lifted this year a certain number of tourists from the vale 

 of Chamouni to the summit of Mont Blanc. 



To most minds, however, the energy of light and heat 

 presents itself as a thing totally distinct from ordinary 

 mechanical energy. Either of them can nevertheless be 

 derived from the other. Wood can be raised by friction 

 to the temperature of ignition; while by properly strik- 

 ing a piece of iron a skilful blacksmith can cause it to 

 glow. Thus, by the rude agency of his hammer, he gen- 

 erates light and heat. This action, if carried far enough, 

 would produce the light and heat of the sun. In fact, 

 the sun's light and heat have actually been referred to 

 the fall of meteoric matter upon his surface; and whether 

 the sun is thus supported or not, it is perfectly certain 

 that he might be thus supported. Whether, moreover, the 



