350 SCIENTIFIC THOUGHT. 



as. And we cannot but be struck by the fact that only those 



Special 



interest dimensions which we call molar appear to be the abode 



attached 



dtaens^ons ^ living an( l conscious beings. The cosmical world has, 

 so far as we know, no inhabitant which can behold it in 

 the same way as man beholds this planet, and the same 

 obtains so far as we are acquainted with the molecular 

 world. So far as our knowledge goes and is likely ever 

 to reach, a special importance or dignity will therefore 

 always belong to molar dimensions and masses. The pro- 

 cess by which we try to picture to ourselves in tracings and 

 models, constructed in molar dimensions, the behaviour 

 and appearance of cosmical as well as molecular masses will 

 always recommend itself, not only as the most practical, but 

 likewise as the most interesting and plausible, for only by 

 this procedure do these unreachable worlds become amen- 

 able to direct observation and to the processes of experi- 

 ment in the physical laboratory. It seems prima facie 

 that the wealth of phenomena and the variety of different 

 kinds of motion decrease as we ascend into the cosmical, 

 or as we descend into the molecular world, giving way 

 in the former to essentially uniform, though to many 

 times multiplied modes of motion, and disappearing in 



I'univers sont inde'pendantes de ses a centre like the sun would be 

 dimensions absolues, cotnme elles F , rn . . 



le sont, du mouvement absolu, j K^ =K x ^ wluch 1S onl y 

 qu'il peut avoir dans 1'espace ; et m 



nous ne pouvons observer et con- times the acceleration ^-, i 



naitre que des rapports." This is [ n = 2 . i n another passage Laplace 



easily seen. For if in the formula repeat3 t h e above statement in 



/=^^, the dimensions be all slightly different words: "L'uni- 



vers reduit successivemeut jusqu'au 



multiplied by K, we get the new ; plus petit espace imaginable, offrir- 



foramk *=*- X, and the ! ? ic toujours les memes apparences 



r a ses observateurs (p. 440). That 



acceleration of a body moving round this would not apply to molecular 



attractions or repulsions is evident. 



