434 Notices respecting New Books. 



on Dr. Roget to prove its imperfection, previously to hid 

 passing such a censure upon it. 



No one is more averse to controversv than myself, and 

 this temper I have endeavoured to mamtain through the 

 whole of this discussion ; as a proof of this, I have constantly 

 endeavoured to render my papers useful to your readers, by 

 dwelling more upon the subject as it concerns chemistry, 

 and less upon that which is connected with my professional 

 character, which, situated as I am, it is my duty to defend; 

 and, in this attempt to improve science, i trust I have so far 

 succeeded as to render this controversy more interesting to 

 your numerous readers than Dr. Roget is willing to allow. 

 I remain, sir, 



Your obedient servant, 



Long-Acre, London, JoS. HUME. 



Dec. 14, 1812. 



LXXVII. Notices respecting New Books. 

 SirHuMPHRvDAVr's" Elements of Chemical Philosophy." 



[Concluded from p. 307.] 



J-N the absence of all decisive general principles to found a 

 theory of electrical phaeiiomena. Sir H. observes, " It would 

 appear, that in all cases of electrical action, the two electri- 

 cal states are always coincident, either in different parts of 

 the same body, or in two bodies; and that they are always 

 equal, and capable of neutralizing each other. If a con- 

 nection be made by a wire, between the positive and nega- 

 tive conductors of the electrical machine, during the time 

 of its action, all electrical effects cease ; and to produce a 

 succession of effects, both conduct rs must be brought 

 near bodies connected with the ground, which gain the op- 

 posite state in consequence of what may be called induction. 

 When a nonconductor, or imperfect conductor, provi- 

 ded it be a thin plate of matter, placed upon a conductor, 

 is brought in contact with an excited electrical body ; the 

 surface, opposite to that in contact, sjains the opposite 

 electricity from that of the excited body ; and if the plate 

 be removed from the conductor and the source of electri- 

 city, it is found to possess two surfaces in opposite slates. 

 If a C(<nductor be brought into the neighbourhood of an 

 excited body, the air, wi^' h is a nonconductor, being be- 

 tween them ; that extremity of the conductor, which is 

 opposite to the excited body, gains the opposite electricity, 

 and the other extremity, if opposite to a body connected 



with " 



