t)fthe Ley den Jar. 407 



futility of his objections to Franklin's theory of charged elec- 

 trics. His first tvt'o experiments are simply these : He presented 

 excited sulphur to the pith-balls connected with the inner 

 surface of liis jar, and observed that they were repelled by 

 the sulphur ; he then presented the same sidpln/r to the balls 

 connected with the outer surface, and observed that they were 

 attracted by it. Now Experiments 2 and 3 of my foregoing 

 series prove that his sulphur, wlien it repelled the balls of the 

 inner surface, was in a positive slate of electricity; and conse- 

 quently, when he presented it to the balls of the outer surface, 

 altrnclion was the necessary consequence. And Experiment 4 

 proves that had he presented the sulphur to the latter balls more 

 tlian twice, he must have discovered that the sulphur after at- 

 tracting would have repelled them. Again, Experiments 1 and 2 

 prove that the balls of the inner surface were attracted by the 

 sulphur lefore they were repelled. Hence it is proved that in 

 making his first two experiments, Mr. Donovan observed only 

 one half of what he ought to have observed ; and, unfortunately 

 for him, this was the wrong half: — such was his attention in ma- 

 king them ! Moreover he neglected to employ any additional 

 means to ascertain the electrical state of either the inner or outer 

 surface of his jar ! He also neglected to examine the electrical 

 .state of his sulphur after it had repelled the balls of the inner 

 surface, and likewise after it had attracted those of the outer 1 

 And not in the least suspecting the electrical change that the 

 sulphur had undergone, but resting perfectly satisfied with his 

 two fallacious observations, he supposed first that the inside of 

 his jar was in a negative, when in reality it was in a positive 

 state of electricity! secondly, that the outside was in a positive 

 state, when in reality it was in a negative one ! and lastly, that his 

 sulphur was in a negative when it really was in a positive state! 

 The results of his two experiments being, as he imagined, so 

 discordant with Franklin's theory, he proceeds thus : " The 

 ERRoa does not relate merely to the surface occupied bv the 

 accunmlation. Let the jar with its wires, balls, &c. be set on 

 the stand as before, but not connected with the ground. Let 

 the jar be charged, and while the cylinder is still turning let the 

 surfaces be examined: it v/iil be found that excited sulphur re- 

 pels the halls of both the inside and outside." — Here again, neg- 

 lecting all other assistance, Mr. Donovan employs his favourite 

 but ungrateful and treacherous sulphur, and is, in the same man- 

 ner as before, deceived by it. He however goes on : " This 

 cannot he explained while it is supposed that the outside is then 

 giving out electricity, urged by the repulsion of the fluid thrown 

 in : for in this case if any body with a diminished quantity, as 

 sulphutj be presented, an attraction ought to follow," True : and 

 C c 4 attraction 



