196 CHARLES BABBAGE. 



we have uttered, earth, air and ocean are the eternal witnesses of the 

 acts we have done. The same principle of the equality of action and 

 reaction applies to them ; whatever movement is communicated to any 

 of their particles is transmitted to all around it, the share of each being 

 diminished by their number, and depending jointly on the number and 

 position of those acted upon by the original sources of disturbance. The 

 waves of air, although in many instances perceptible to the organs of 

 hearing, are only rendered visible to the eye by peculiar contrivances ; 

 but those of water offer to the sense of sight the most beautiful illustra- 

 tion of transmitted motion. Every one who has thrown a pebble into 

 the still waters of a sheltered pool has seen the circles it has raised, 

 gradually expanding in size, and as uniformly diminishing in distinct- 

 ness. He may have observed the reflection of those waves from the edges 

 of the pool. He may have noticed also the perfect distinctness with 

 which two, three, or more series of waves each pursues its own unim- 

 peded course, when diverging from two, three, or more centers of dis- 

 turbance. He may have seen, in such cases, the particles of water 

 where the waves intersect each other partake of the movements due to 

 each series. 



No motion impressed by natural causes or by human agency is ever 

 obliterated. The ripple on the ocean's surface, caused by a gentle breeze, 

 or the still water which marks the more immediate track of a ponderous 

 vessel gliding with scarcely expanded sails over its bosom, are equally 

 indelible. The momentary waves raised by the passing breeze, appa- 

 rently born but to die on the spot which saw their birth, leave behind 

 them an endless progeny, which, reviving with diminished energy in 

 other seas, resisting a thousand shores, reflected from each, and per- 

 haps again partially concentrated, will pursue their ceaseless course till 

 ocean be itself annihilated. 



The track of every canoe, of every vessel which has yet disturbed the 

 surface of the ocean, whether impelled by manual force or elemental 

 power, remains forever registered in the future movement of all suc- 

 ceeding particles which may occupy its place. The furrow which it 

 *eft is, indeed, instantly filled up by the closing waters 5 but they draw 

 after them other and larger portions of the surrounding element, and 

 these again once moved communicate motion to others in endless suc- 

 cession. 



The solid substance of the globe itself, whether we regard the minutest 

 movement of the soft clay which receives its impression from the foot of 

 animals, or the concussion arising from the fall of mountains rent by 

 earthquakes, equally communicates and retains, through all its count- 

 less atoms, their apportioned shares of the motions so impressed. 



While the atmosphere we breathe is the ever-living witness of the 

 sentinients we have uttered, the waters, and the more solid materials 

 of the globe, bear equally enduring testimony of the acts we have com- 

 mitted. 



