No. XII.] APPENDIX. 201 



attraction is always exerted in a peculiar direction, a series of which 

 attractions constitutes polarity ; and " this peculiarity in the direction of 

 the force, whereby attraction is exerted, is of fundamental importance, for 

 it enables us to oppose one attraction by another. This opposition of 

 attraction enables us to effect decomposition, disintegration, and to give 

 rise to the phenomena of heat, light, sound, &c., at will." 



The author now proceeds to examine seriatim the various properties 

 of matter, and to show how they are derived from simple attraction ; and 

 the first of those which he touches upon is what is called impenetrability, 

 which literally means that two bodies cannot occupy the same space at the 

 same time. This he explains thus : 



" The reason why impenetrability is conferred on matter by the act 

 of attraction is perfectly evident, if the mode of the generation of attraction 

 be carefully examined. The attraction being exerted in a certain direction, 

 one particle of matter, although capable of being attracted so as to adhere 

 firmly to a second portion, would, if the second passed into the first, 

 instantly be destroyed, because the direction of attraction exerted in one 

 atom would oppose, neutralize, or counterbalance the attraction in the 

 other. The attraction, therefore, between two atoms is most violent at 

 contact, but ceases upon one having a tendency to pass into the other. 

 The above observations will be rendered perfectly intelligible by the 

 following notation : 



NP NP 



O O 



" If the two O O represent the two atoms, and the NP NP the ends of 

 the forces with which they are held together, then the very moment one 

 atom had a tendency to pass into the other, the two ' N ' or the two ' P ' 

 would oppose each other ; upon that account the two particles would be 

 firmly attracted till they came in contact, but no further." P. 26. 



Having briefly alluded to shape, he next comes to the volume of bodies, 

 which he shows to be far from an inherent fixed property, but merely to 

 depend on the energy with which attraction is exerted. "We have no 

 proof that matter possesses any absolute volume, for, under different cir- 

 cumstances, the same number of particles exhibits very various volumes." 



" Volume, from the above consideration, seems rather a negative than 

 a positive quality. It is the absence, or the comparative absence, of 

 attraction ; for as the force increases, the volume diminishes. The advan- 

 tages of thus viewing the nature of volume are multifold. It does not 

 require the creation of ' repulsion ' to separate particles attracted together, 

 and it overcomes numerous difficulties which arise from the assumption of 

 a certain size to the ultimate particles of matter. From this view, which 

 is forced upon us from multitudinous evidence, one atom of matter, if 

 alone, and unacted upon by any other atom, would fill the universe." 

 P. 28. 



He next speaks of the science by which size and measure are estimated. 

 The following observations, on the impossibility of finding a standard unit 

 of measure, are interesting enough : 



" But as our organs of sense cannot appreciate the ultimate particles 

 of matter, we never can arrive at, or obtain, an absolute standard of size ; 

 on this account we are compelled to take a certain piece of matter under 



