UNLIMITED DIVISIBILITY. 



Solids, generally, by means of heat applied in sufficient quantity 

 and under fit conditions, maybe made to pass into the liquid state, 

 the process being called fusion or liquefaction, and all liquids may 

 by like means be made to pass into the gaseous or vaporous state, 

 the process being called vaporisation. 



In like manner gases and vapours generally may, by the abstrac- 

 tion of heat, be made to pass into the liquid state, the process being 

 called condensation, and liquids in like manner may be made to 

 pass into the solid state, the process being called congelation or 

 solidification. 



In producing these changes upon particular substances, there 

 have been practical difficulties which have pi evented the success 

 of the operation, but all analogy supports the conclusion that the 

 principle is general. 



These changes, produced by the supply and abstraction of heat, 

 have furnished some of the most efficacious means of determining 

 the nature and properties of the minute component parts of bodies. 



9. Bodies may, however, without other physical agency than 

 mere mechanical subdivision, be reduced to particles of surprising 

 minuteness. 



As this quality of unlimited divisibility involves conditions of 

 the most profound interest, as well in the sciences as in the arts, 

 we shall offer here several examples in illustration of it. 



10. The most solid bodies are capable of unlimited comminu- 

 tion, by a variety of mechanical processes, such as cutting, filing, 

 pounding, grinding, &c. If a mass of marble be reduced to 

 a fine powder by the process of grinding, and this powder be 

 then purified by careful washing, its particles, if examined by a 

 powerful microscope, will be found to consist of blocks having 

 rhomboidal forms, and angles as perfect and as accurate as the finest 

 specimens of calcareous spars. These rhomboids, minute as they 

 are, may be again broken and pulverized, and the particles into 

 which they are divided will still be rhomboids of the same form 

 and possessing the same character. The particles of such powder 

 being submitted to the most powerful microscopic instruments, and 

 the process of pulverization being pushed to the utmost practical 

 limit, it is still found that the same forms are reproduced. 



11. The polish of which the surfaces of certain bodies, such as 

 steel, the diamond and other precious stones, are susceptible, is an 

 evidence at once of the limited sensibility of our organs, and the 

 unlimited divisibility of matter. This polish is produced, as is 

 well known, by the friction of emery powder or diamond dust, and 

 consequently each individual grain of such powder or dust must 

 leave a little trench or trace upon the surface submitted to such 

 friction. It is evident, therefore, that after this process has been 



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