Chap. 35.] cf Animal Ekftricity. 357 



tion in paffing from link to link of feveral chains, 

 even when no preffure, except that of their own 

 weight, is ufed to bring them into contact. Dr. 

 Fowler was led from this to hope, that he Ihould be 

 able to make it pafs through a very thin plate of air* 

 He therefore coated a flick of fealing-wax with a plate 

 of tin-foil, and then made an almoft imperceptible 

 divifion acrofs it with a fharp pen-knife j but even this 

 interruption of continuity in the conductor was fufficient 

 effectually to prevent its pafTage. 



Dr, Fowler next proceeds to examine whether the 

 capacity of different fubftances, as conductors or non- 

 conductors, was at all affected by differences of their 

 temperature ; but this was not the caie wiih zinc, iron, 

 water, coal, or a common crucible, the only Jubilances 

 with which he tried the experiment. 



The effects of this influence may be felt in ourfelve^s 

 by a very eafy experiment. If a piece of lead is ap- 

 plied to the upper part of the point of the tongue, 

 while a piece of filver is applied to the under part, 

 upon bringing the two metals into contact, a fomewhat 

 pungent fenfation will be felt, accompanied by aftrong 

 metalline tafle of fome duration. The fame fenfa- 

 tion takes place though both of the metals are pre- 

 vented from touching the tongue by the interpofitibn 

 of moiftened paper, 



Dr. Fowler fays, he could never perceive that the 

 fenfes either of touch or fmell were in the lead affected 

 by the rnetals ; but the effect which they produce on 

 they eye is very remarkable. Having laid a piece of 

 tin-foil on the point of his tongue, he placed the 

 rounded end of a filver pencil-cafe againft the ball of 

 his eye, in the inner canthus, and fuffered them to re- 

 main in thefe fituations till the parts were fo accuftomed 

 $Q them, that /he could examine the fenfations pro- 

 A a 3 duced \ 



