172 DISCOURSE ON THE STUDY 



of that condensation which necessarily takes place at 

 every vibration by which sound is conveyed. Thg 

 matter was subjected to exact calculation, and the 

 result was at once the complete explanation of the 

 residual phenomenon, and a striking confirmation 

 of the general law of the developement of heat by 

 compression, under circumstances beyond artificial 

 imitation. 



(182.) In extending our inductions to cases not 

 originally contemplated, there is one step which 

 always strikes the mind with peculiar force, and with 

 such a sensation of novelty and surprise, as often 

 gives it a weight beyond its due philosophic value. 

 It is the transition from the little to the great, and 

 vice versa, but especially the former. It is so beau- 

 tiful to see, for instance, an experiment performed 

 in a watch-glass, or before a blowpipe, succeed, in a 

 great manufactory, on many tons of matter, or, in the 

 bosom of a volcano, upon millions of cubic fathoms 

 of lava, that we almost forget that these great masses 

 are made up of watch-glassfuls, and blowpipe- 

 beads. We see the enormous intervals between the 

 stars and planets of the heavens, which afford room 

 for innumerable processes to be carried on, for 

 light and heat to circulate, and for curious and 

 complicated motions to go forward among them : 

 we look more attentively, and we see sidereal sys- 

 tems, probably not less vast and complicated than our 

 own, crowded apparently into a small space (from 

 the effect of their distance from us), and forming 

 groups resembling bodies of a substantial appear- 

 ance, having form and outline : yet we recoil with 

 incredulous surprise when we are asked why we 



