Intelligence and Miscellaneous Articles. 233 



Very different indeed are the results from the unio- directive 

 discharger. Electro-dynamic phenomena, by this apparatus, are 

 exhibited from revolving coils, either with or without a ferruginous 

 nucleus or armature, with the same promptitude, uniformity, and 

 precision as by any other source hitherto placed in the hands of the 

 philosopher. 



The experimenter also, by this means, may safely confide in his 

 predictions, and vary his exhibitions in any way he pleases, as far 

 as the energy of the currents will permit. He is thus relieved from 

 all those corroding apprehensions and mortifying disappointments, 

 which must ever molest his efforts, agonize his feelings, and chill 

 the ardour of his inquiries, whilst operating with an apparatus over 

 the powers of which he has not the slightest control. 



That these facts might appear unfettered and without disguise, 

 I have rigidly abstained from touching on any of the assailable 

 points which are distinguishable in Mr. Watkins's last paper, with 

 the exception of those which appeared absolutely necessary for 

 placing in a proper light the obvious distinction of our claims. 



The following particulars may possibly be interesting to those 

 engaged in magnetic electricity. 



I produce electric shocks, sparks, steady deflections of the 

 needle, electro-magnetic rotations, &c, and chemical decomposi- 

 tion with exact polar arrangement of the liberated constituents, by 

 the following forms of magnetic electrometers : 



1. By revolving coils of copper wire between the poles of either 

 a horse-shoe or a compound bar magnet, so as that the wire may 

 strike, at right angles, the most formidable group of magnetic lines, 

 as shown in my theory of magnetic electricity. (See Lond. and 

 Edinb. Phil. Mag., vol. i.p. 31.) 



With the exception of my revolving discs, described in the Phil. 

 Mag. for April 1832 ( Phil. Mag. and Annals, N.S., vol. xi. p. 270.), 

 this is the oldest of my magnetic electrometers. But for want of 

 a sufficiently powerful magnet it was a long time before I had much 

 satisfaction from it. 1 have more recently been better provided, 

 and I find that it acts well; and appears to me to be better ciilcu- 

 lated for some points of inquiry than any other form I have yet seen. 



2. By revolving coils of wire (having an iron axis or armature) in 

 front of the poles of a horse- shoe magnet. My first revolving arma- 

 ture was simply a straight piece of iron carrying a coil of wire, 

 and revolving in a horizontal plane above the poles of a vertical 

 electro-magnet. The idea of this form occurred whilst Mr.Watkins 

 was describing to me the well-known apparatus of M. Pixii, an 

 account of which had reached him a short time before. With this 

 form I never did anything more than produce a feeble spark . 



In the autumn of 1833, I first saw, in its present state, the 

 splendid apparatus in the Adelaide Exhibition Rooms, made by 

 Mr. Saxton. This modification of M. Pixii's electrometer far ex- 

 ceeding in power my puny arrangement, I have, from that time, 

 employed bent armature and two coils in the manner of Mr. Sax- 

 ton. 



Third Series. Vol. 7. No. 39. Sept. 1835. 2 H 



