68 Notices respecting New Books, 



physics, viz. heat, light, electricity, magnetism, chemical affinity and 

 motion, are all correlative, or have a reciprocal dependence ; that 

 neither, taken abstractedly, can be said to be the essential or proxi- 

 mate cause of the others, but that either may, as a force, produce 

 or be convertible into the other ; thus heat may mediately or imme- 

 diately produce electricity, electricity may produce heat ; and so of 

 the rest." 



In further illustration of the author's views, we may quote what 

 he states to be the sense that he has attached to the word correlation, 

 which is, that " of a reciprocal production or convertibility ; in other 

 words, that any force capable of producing or being convertible into 

 another, may, in its turn, be produced by it, — nay, more, can be 

 itself resisted by the force it produces, in proportion to the energy 

 of such production, as action is ever accompanied and resisted by 

 reaction ; thus, the action of an electro- magnetic machine is reacted 

 upon by the magneto-electricity developed by its action." 



In order to support his speculations by facts, the author appeals 

 in the first place to the agency of electricity. " To commence, then, 

 with electricity as an initiating force, we get motion directly pro- 

 duced by it in various forms ; for instance in the attraction and re- 

 pulsion of bodies, evidenced by mobile electrometers, such as that of 

 Cuthbertson, where large masses are acted on ; the rotation of the 

 fly wheel, another form of electrical repulsion, and the deflection of 

 the galvanometer needle, are also modes of j)alpable, visible motion. 

 Electricity directly produces heat, as shown in the ignited wire, the 

 electric spark, and the voltaic arc, in the latter the most intense heat 

 with which we are acquainted, so intense, indeed, that it cannot be 

 measured, every sort of matter being dissipated by it. Electricity 

 directly produces light in the same pha?nomena. It directly produces 

 magnetism in all ferruginous bodies placed at right angles to its line 

 of direction, and, indeed, in the substances, of whatever nature, 

 traversed by the electrical current, in a direction at right angles to 

 that of the current ; in this case giving us a new character of force, 

 viz., a force acting, not in direct straight lines, but in a tangential or 

 rather rectangular direction. 



" Lastly, electricity directly produces chemical affinity, and by its 

 agency we are enabled to obtain efi^ects of analysis or synthesis, with 

 which ordinary chemistry does not furnish us. Of these effects we 

 have examples in the brilliant discoveries by Davy of the alkaline 

 metals, and in the peculiar crystalline compounds made known by 

 Crosse and Becquerel." 



Having stated thus much respecting electricity in support of his 

 peculiar views, Mr. Grove adduces additional confirmation of them 

 from considering the action of light, in a passage which we shall 

 quote at length. He observes that "light is, perhaps, that mode of 

 force the reciprocal relations of which with the others has been the 

 least traced out. Until the discoveries of Daguerre and Talbot, very 

 little could be definitely predicated of the action of light in produ- 

 cing other modes of f^rce ; and, even, since these discoveries, it is 

 doubted by many competent investigators, whether the phsenomena 



