124 ATOMS AND SUNBEAMS. 



objects wliich could be seen in tlie microscope, we tlien approach tbe 

 limits of i)artition of wliicli the diamonds wonld be snsceptible. We 

 now know that there is an atom of diamond so small that it must refuse 

 to undergo any further division. This ultimate atom, be it observed, 

 is not an infinitely small quantity. It has definite dimensions; it pos- 

 sesses a definite weight. All such diamond atoms are precisely alike 

 in weight, and probably in other characteristics. It might be thought 

 that if this atom has finite dimensions, it is, at all events, conceivable 

 that it should admit of further subdivision. In a certain sense this is, 

 no doubt, the case. The diamond atom is made up of parts and being 

 so made it is of course conceivable that tliose parts could be separated. 

 The important point to notice is, that no means known to us could pro- 

 duce this separation, while it is perfectly certain that if the decompo- 

 sition of the atom of diamond into distinct parts could l)e affected, those 

 parts would not be diamonds at all, nor anything in the least resembling 

 diamonds. 



What we have said as regards the element carbon may be extended 

 to every other elementary substance. Sulphur is familiarly known in 

 a form of extreme subdivision, and each little particle of suli^hur could 

 be further comminuted to a certaiu point beyond which any further 

 partition would be impossible. So too any composite body, such for 

 example as a, lump of sugar, admits of being decomposed into mole- 

 cules so small that any further separation would be impossible if the 

 molecule were still to remain sugar. No doubt, a separation of the 

 molecule of any composite body into constituent atoms of other elements 

 is not alone possible but is incessantly taking place. 



The first step in our knowledge of the constitution of matter has been 

 taken when we have come to re(;ognize that every body is composed of 

 a multitude of extremely, but not infinitely, small molecules. The next 

 l)oint relates to the condition in which these molecules are found. At 

 first it might be thought that in a solid, at all events, the little particles 

 must be clustered together in a compact mass. If we depended merely 

 on sensible evidence it would seem that a lump of iron, if constituted 

 from molecules at all, nuistbe simply a cohering massof particles, .just 

 as a multitude of particles of sand unite to form a lump of sandstone. 

 But the truth is far . more wonderful than such a belief would imply. 

 Were the sensibility of our eyes so greatly increased as to make them 

 a few million times more powerful than our present organs, then indeed 

 the display of the texture of solid matter would be an astonishing rev- 

 elation. It would be seen that the diamond atoms, which, when aggre- 

 gated in sufficient myriads, form the i^erfect gem, were each in a condi- 

 tion of rapid movement of the most complex description ; each molecule 

 would be seen swinging to and fro with the utmost violence among the 

 neighboring molecules. It would be seen quivering all over under the 

 influence of the shocks which it would receive from the vehement en- 

 counters with other molecules which occur millions of times in each 



