Otr the Phcenamena of the Elcctrcphcnts. 299 



testored ; for a considerable degree of attraction may be 

 observed between the upper coating and the gla?s, which 

 is frequently strong enough to !ift a piece of plate glass 

 weighing ten ounces. Neither coaling ■will now shov the 

 least external sign of electricity when in contact with the 

 glass ; but on separation, carefully preserving the insula- 

 tion, the upper coating is strongly negative, the under po- 

 sitive. Let both coatings be restored to their natural state 

 by contact with a conductor, and then replace the glass 

 between them : if the upper coating be touched and sepa- 

 rated it will give no spark, but on touching the coatings 

 alternately several times it u'ill give a weak spark; and this 

 may b' repeated several times by only touching the upper 

 coating. On a second application of the bent wire to 

 both coatings, a second though nuich slighter discharge 

 is perceptible, and the coatings are brought into the same 

 electrical state as inmiediately after the first dit^charge. 

 This may frequently be repeated, and a considerable 

 number of strong negative sparks taken from the coating 

 when separated from the positive surface of the glass. If 

 the glass in replacing it between the coatings be reversed, 

 the electrical powers of both coatings will be changed by 

 the next application of the discharging-wire, and a succes- 

 sion of strong positive sparks obtained from the negative 

 surface of the glass. 



" 7. Mence it may be inferred that the charged n;la3s was 

 not restored to its natural state by the completion of the 

 circuit, but that it had acquired a degree of permanent elec- 

 tricity. 



** 8. The whole quantity of electric matter added to the 

 'glass in charging it, is evidently distintniishablc into two 

 parts : the first part, by far the most considerable, is readilv 

 communicated along the bent wire from one surface to the 

 other; the second part appears more permanent, and re- 

 mains s^ill united with tlie glass. It appears, therefore, 

 from the preceding experiments that professor Volta's elec- 

 trophoriis is in reality a resinous plate charged with perma- 

 nent electricity by friction." 



I should observe, that the above accomit of Mr. Milncr's 

 investigation is extracted ironi the Evcyclopa'dia Bntannka\ 

 but, though marked with inverted commas, is not precisely 

 in the language of the ingenious author \ the whole, extend- 

 ing to a very considerable length, h;is been condensed and 

 abridircd, but, I tru.st, without any misrepresentation of 

 meaiung. Let us now proceed to Mr. Morgan's examina- 

 tion of an excited substance. 



" Let 



