Newton, Leibnitz, and Boscovich to the Atomic Theory. 61 



escape, or to screen anything, whether in nature or the laboratory. 

 Call them electric or by any other name, these currents modify every- 

 thing, and make every object to be different from w^hat it would be 

 if developed as an individual far out in space, under no influences but 

 those attaching to itself. 



1. Hence all indivi- 

 dualized molecules and 

 combinations viewed as 

 insulated, or as defined 

 by their self-insulating 

 atmospheres, may be 

 distributed into two 

 grand classes, viz., those 

 which depart from the 

 spherical by having too 

 mucli matter on the 

 axial region, rendering them prolate (see fig. H*^) , and those which have 

 too much matter on the equatorial region, rendering them ohlate (see 

 fig. H*). 



2. Hence also a primary condition in the construction of a molecule 

 is, that it shall have one part which may be called its equatorial region, 

 and two others in geometrical relation with it, which may be called its 

 polar regions. And in reference to the latter, we may here remark, 

 that the most urgent condition to individuality, insulability, and repose 

 in the molecule is, that they be similar to one another, and the mole- 

 cule may be, as we may say, homopolar. 



Laws of Chemical Union. 



Such being the first lines of morphology under the law of assimi- 

 lation, let us now suppose that two dissimilar molecules are brought 

 into the presence of each other, and let us see what phenomena must 

 arise under our grand law, viewed now in the second phase of its 

 agency, that is, as a nisus or tendency towards mutual assimilation, 

 — a nisus or tendency in each atom, molecule, or mass, to induce its own 

 features upon the other. And here many cases present themselves, thus, 



1. We may suppose more powerful molecules to be mixed with such 

 as are weaker, and so related that they do not tend to the genesis of 

 a new species by rushing into union with the former. The law of assi- 

 milation leads us in such a case to infer, that those which are more 

 powerful will succeed more or less in impressing their own features upon 

 those that are weaker. Thus let a molecule of a powerful and stable 

 kind be brought into the presence of such as are tending to spontaneous 



