408 071 the Franklinian Theory of the Ley den Jar. 



attraction did follow ; but Mr. Donovan's attention was not suf- 

 ficiently alive to observe it. " When the charging," says he, 

 *' is disconrinneri, another militating-, phaenomenon occurs: the 

 balls colhiv)'^e ; and after touching, again sepaiate, l)nt with a 

 different power, for they are now attracted by excited sulphur." 

 The last clause in the preceding sentence shows that Mr. Do- 

 novan presented the same sulphur to the balls of the outside 

 after they had collapsed, that he had the inonient l>efore ])resent.ed 

 to them while they were evolving positive electricity in conse- 

 quence of the action of the machine : the sulphur tl\erefore 

 which had become positive in that experiment attrai.-ted the 

 balls now, because, the action of the machine having ceased, 

 they were actually in a negative state in consequence of the 

 electricity which had been evolved, and had departed from the 

 outside during the previous experiment. But Mr. Donovan, still 

 unconscious of the errors into which he had Ijeen seduced by 

 placing implicit confidence in the mischievous sulphur, thus pro- 

 ceeds : 



'^ Here then are strong instances which oppose the Franklinian 

 hypothesis : it appears that the supposed excess may evince the 

 symptoms of a state of diminution without any abstraction hav- 

 ing taken place ; and the diminution may appear to be an ex- 

 cess without any addition." These truly are singular disco- 

 veries, all made by Mr. Donovan and his sulphur ! And as he 

 terminates with these discoveries his inquiry concerning the elec- 

 trical states of a charged jar, so likewise with them shall termi- 

 nate my examination of that inquiry. And I shall add only that 

 if, at first view, it should seem that I have entered more into the 

 detail of experiments than was necessary to demonstrate Mr. 

 Donovan's errors, the circumstances under which his Reflections 

 have been ushered into public notice must be considered. Now 

 it appears that the Metnoir or Essay, of which the Reflections 

 are an abridgement, was read to a learned and respectable So- 

 ciety, of which Mr. Donovan is himself the Secretary*; that the 

 above Essay was honoured with the prize by the Royal Irish 

 Academy t; and that the author communicated the Reflections 

 to you, sir, for insertion in your valuable Magazine*. He must 

 therefore have considered his Reflections entitled to attention ; 

 and a superficial examination of his experiments and opinions 

 would not have been either satisfactory to the author, or of any 

 use to the inexperienced electrician, who would still have been 

 HI danger of being misled by them. 



I ain, sir, with great respect. 



Your obliged servant, 

 Hereford, Nov. 13, 1815. ThoMAS HowldY. 



* Phil. Mag. vol. xliv. p. 334. f lb. vol. xlv, p. 222. 



LXXIV. An 



