Chap. 3.] tie Frarikttman 'Theory. 327 



that of two bodies ne'gatively electrified repelling each 

 other, for if the repulfisn in the cafe of pofitive elec- 

 tricity is caufed entirely, as there is reafon to believe 

 it is, by the electric matter, how mould a deficiency of 

 that matter produce the fame effect ? Attempts have 

 been made to explain the fact by having recourfe to 

 the electricity of the air, which (when not charged with 

 moifture) is certainly an electric or non-condur.ing 

 fubitance, and in all cafes is an imperfect electric. The 

 cork balls, or other light fubftances, which are electri- 

 fied negatively, are therefore fuppofed to be acted 

 upon by the pofitive electricity of the air, which pro- 

 duce.s an effect adequate to their being pofitively elec- 

 trified. This folution, however, is not quite fatisfac- 

 tory; though it is perhaps unphilofophical to reject an 

 hypothefis, which explains fome facts greatly to our 

 fatisfaction, merely becaufe it has not as yet explained 

 every thing. 



Dr. Franklin fuppofed that the electric fluid is col- 

 lected from the earth, and this hypothefis he fupported 

 by the following experiment. 



Let one perfon ftand on wax (or be iniulaceci) and 

 rub a glafs tube, and let another perfon en wax take 

 the fire from the firft, they will both of them (provid- 

 ed they do not touch eaerr other) appear to be electri- 

 fied to a perfon {landing on the floor ; that is, he will 

 perceive a fpark on approaching either of them with 

 his knuckle or finger ; but if they touch each other 

 during the excitation of the tube, neither of them will 

 appear to be electrified. If they touch one another 

 after exciting the tube, and draw the fire as before, 

 there will be a ftronger fpark between therrj than was 

 between either of them and the perfon on the floor. 

 After fuch a ftrong fpark neither of them difcover &ny 

 tkffricity* 



Y 4 He 



