386 Prof. Norton on Molecular Physics. 



that of m, it is possible that in special cases the final result may- 

 be an inequality of disturbance, so that m and m { will attract n 

 unequally, and the position of equilibrium assumed by it will in 

 consequence not be opposite the middle of the interval between 

 m and m l . In this case the electric atmosphere of n will have a 

 form differently modified, and its second axis will be oblique to 

 the line of primary crystallization in which the axis first deve- 

 loped lies. 



The figure first assumed must then depend upon the funda- 

 mental properties, with respect to heat, &c, of the individual 

 molecules of the substance ; and the general tendency must be, 

 for the first group of molecules to acquire increased dimensions 

 by successive solidifications of a series of figures similar to the 

 first. 



In what precedes, we have had regard only to the play of the 

 ordinary molecular forces, and the modifications which the ordi- 

 nary molecular action may experience from the loss of heat, and 

 in the act of solidification ; but there must result in each instance 

 of the union of two particles a modification of the condition of 

 their atmospheres, which should develope a new force of attrac- 

 tion that may play an important part in the continuation of the 

 process of crystallization. For when two particles unite by 

 crystallization, their atmospheres on their nearer sides will be- 

 come compressed, and consequently on their further sides ex- 

 panded. Each molecule will thus virtually be brought into an 

 electro-polar condition, with the positive pole turned outward. 

 This positive pole, or excess of electric sether, tends to bring all 

 the molecules lying in the prolongation of the line of the first 

 two into the same electro-polar condition, and in this state of 

 induced polarization a force of electric attraction will subsist 

 between the particles. As one particle after another in the line 

 comes to unite with those previously crystallized, its previous 

 polarization will be enhanced, and it will exert an increased 

 attractive force upon those not yet crystallized. At the same 

 time, by the compressive and repulsive action of the contiguous 

 atmospheres, the particle with which the new one unites will 

 lose a considerable portion of its polarity. This reflex action, 

 attendant upon every act of union, should eventually greatly 

 diminish, if not wholly remove, the prior induced polarization. 



Another effect of this reflex action to be noticed is, the in- 

 creased expansion of the atmosphere of the molecule which 

 experiences the reactive compression in the direction perpendi- 

 cular to the line of crystallization. This molecule thus acquires 

 an increased positive polarization on the outer side, lying in this 

 perpendicular direction, and therefore exerts an increased force 

 of electric attraction in this direction. In the varying operation 



