DIVISIBILITY OF MATTER ATOMIC THEORY. 65 



inter-relations of its component atoms. These atomic 

 changes are such in kind as to show the individuality 

 of the parts so-called, however inconceivable their 

 minuteness. 



To this individuality are attached some of the most 

 profound questions in modern science. First comes 

 the old metaphysical difficulty. Is there any thing 

 actually indivisible ? Can we speak of, or conceive, a 

 material unit without parts ? Remitting this ques- 

 tion, as may well be done, to that limbo of the Infinite 

 in which so many others are merged, we encounter 

 various problems more capable of solution, but not 

 yet thoroughly solved. What, for example, are those 

 properties or endowments, manifestly inherent in the 

 very nature of the ultimate fractional parts of matter, 

 giving them their affinities, repulsions, &c. inter se, and 

 in their relation to the forces which put them into 

 action ? Are there absolute intrinsic differences in the 

 nature of atoms or monads, corresponding to our re- 

 ceived catalogue of elementary bodies ? Or must we 

 receive the latter as an approximation merely to fewer 

 and simpler elements, to be determined as such by a 

 future more subtle analysis ? How are we to regard 

 the phenomena of allotropy occurring in substances 

 hitherto deemed elementary ? Or the atomic pheno- 

 mena of crystallisation and their various relations to 

 light, heat, and electricity ? Or the strange fact, 

 necessarily blending itself with the atomic theory, that 

 the properties of substances may in many cases be dis- 

 tinctly altered by admixture with infinitesimal propor- 



