Prof. Norton on Molecular Physics. 97 



magnetism, magneto -electricity, induced currents, and diamagnetism 

 may be derived as mechanical deductions from the same funda- 

 mental conceptions. 



We have thus far had no occasion to introduce arbitrary hypo- 

 theses, but have in fact discarded those hitherto in vogue, as 

 that of the permanent polarity of atoms, and various hypotheses 

 as to the mode by which such polarity is constituted and main- 

 tained. It will be seen that in the wide field we are now enter- 

 ing the same fundamental ideas will suffice, and that the same 

 two forces, attraction and repulsion, operating on the same three 

 forms of matter, are alone concerned in evolving the phenomena. 

 In every different province that we enter we but recognize new 

 results achieved by the same agencies, working by the same 

 essential processes. As transcendentally wonderful as is the infi- 

 nite variety of Nature, no less so is the all-comprehensive unity 

 of its origin, and the grand simplicity of its evolution. From 

 the point of view now taken, this truth, which has long been 

 discerned with more or less distinctness, stands forth in its full 

 proportions. In the discussion of specific properties of different 

 substances, we have admitted, and shall continue to admit, only 

 differences in degree, not in kind, and differences, too, that fall 

 within the scope of the general theory. No higher requirement 

 than this can reasonably be exacted of any fundamental concep- 

 tion*. 



Electricity. 



Preparatory to the discussion of this topic, it is important to 

 inquire more minutely than has hitherto been done into the 

 electric condition of molecules, both simple and compound. 

 Each simple atom, as we have seen, is surrounded by an electric 

 atmosphere ; but has this atmosphere a definite limit ? and if so, 

 what is the condition of the electric aether exterior to it, and in 

 the interstices between molecules ? The equilibrium of such an 

 atmosphere is determined by the operation of two antagonistic 

 forces, the attraction of the central atom for each atomette of the 

 atmosphere, and the repulsion experienced by such atomettes 

 from all the others of which the atmosphere is composed. If 

 we regard these forces as in no degree intercepted in their pro- 

 pagation, the atmosphere will extend with decreasing density to 

 that height at which the attraction exerted by the central atom 

 upon an atomette is just neutralized by the repulsion exerted 



* The author may seem to have adopted, in the scheme of molecular 

 forces presented on pages 195 and 196, an arbitrary hypothesis in assuming 

 the existence of a force of molecular repulsion between the surfaces of con- 

 tiguous electric atmospheres, as the grounds upon which the theoretical 

 inference was drawn were not stated in the course of the discussion. There 

 will soon be occasion to offer these in another connexion. 



Phil. Mag. S. 4. Vol. 30. No. 201. Aug. 1865. H 



