96 Mr. H, Wilde's Experimental Researches 



companiment of at least a correlative amount of electricity evolved 

 from the magneto-electric machine, cither all at once in a large 

 quantity, or by a continuous succession of small quantities (45, 

 46), — the power which the metals (but more particularly iron) 

 possess of accumulating and retaining a temporary charge of elec- 

 tricity, or of magnetism, or of both together (according to the 

 mode in which these forces are viewed by physicists), giving rise 

 to the paradoxical phenomena which form the subject of this 

 research*. 



§ 2. On a new and powerful Generator of Dynamic Electricity . 



55. The fact that a large amount of magnetism can be deve- 

 loped in an electromagnet by means of a permanent magnet of 

 much smaller power having been established, and as from the 

 first series of experiments (Table I.) it was shown that definite 

 quantities of magnetism are accompanied by the evolution of 

 proportionate quantities of dynamic electricity, and since an 

 electromagnet when excited by means of a voltaic battery pos- 



* Since the publication of the abstract of this paper in the Proceedings 

 of the Royal Society, my attention has been directed to several accounts of 

 experiments in which electromagnets, excited by means of magneto-electric 

 machines, have been made to sustain considerable weights. The most im- 

 portant of these accounts which have come under my notice, is one con- 

 tained in Silliman's Journal of Science for 1845, vol. xlviii. p. 393, in which 

 it is stated that Dr. Page, by means of a magneto-electric machine, made 

 an electromagnet sustain a weight of 1000 lbs. 



Another account to which I have been referred is contained in a ' Trea- 

 tise on the Electric Telegraph/ by M- l'Abbe Moigno, Paris, 1849, in which 

 it is stated (page 15, p. 72 in the second edition) that the Abbes Moigno 

 and Raillard, by means of a small machine, made an electromagnet sustain 

 a weight of 600 kilogrammes. 



In neither of these accounts, however, does any direct comparison appear 

 to have been made between the sustaining-power of the permanent and the 

 electromagnets, as no mention is therein made of the sustaining-power of 

 the permanent magnets, nor are they (the permanent magnets) specifically 

 mentioned. 



In a brief notice of my experiments which appeared in Les Mondes of 

 September 6, 1866, of which journal M. l'Abbe Moigno is the editor, he 

 gives what professes to be a quotation from his Traite de Telegraphie 

 E'lectrique, in which he has introduced a statement specifying the sustain- 

 ing-power of the permanent magnets used in his experiments, although no 

 such statement is to be found in the treatise from which the quotation is 

 taken. 



Another discrepancy with reference to the account of Moigno's experi- 

 ments also occurs in an article on " Wilde's Magneto-electric Machine," in 

 the Quarterly Journal of Science for October 1866, in which the writer 

 would seem to have mistaken a small electromagnet (used only as an ad- 

 junct to a magneto-electric machine, and which Moigno states would only 

 support a few grammes) for the permanent magnets which excited the 

 electromagnet ; and from this error it is made to appear that the perma- 

 nent magnets used by Moigno would only sustain a few grammes. 



