224 SCIENTIFIC NEWS. 



different points, a ftrong electric charge is pafled through the 



apparatus. At the inftant of the operation, a luminous flafh 



partes from the pofitive conductor, Hides along the furface of 



penetrated oppo- the card, and perforates it oppofite the negative conductor. 



Jato. " This ha PP ens even when the card is perforated beforehand, 



oppofite the pofitive conductor. 



From this fact it has been concluded, that in order to fup- 

 port the theory of two fluids, we mutt fuppofe that one of 

 them efcapes from bodies and produces light, while the other 

 remains inherent*. Cit. Tremery deftroys this reafoning by 

 the following experiment : 



This does not He places the card and the two conductors under the re* 



happen in rare- ce i ver f an a ; r p Um p, and in proportion as the air is ex- 

 haufted, the place of fracture happens neareft the pofitive con- 

 ductor ; and when the air is half exhaufted, the point is pre- 

 cifely at the middle between the two conductors. At every 

 difcharge a luminous trace iffues from each conductor along 

 the furface of the card to the place of intersection. 



Inferences. From this experiment, Cit. Tremery concludes that the at- 



mofpheric air, in its ordinary ftate, refills the paffage of the 

 negative more than the pofitive fluid +. Thefe refiftances are 

 diftinguifhed in different ratios, with regard to the two fluids 

 as the air becomes lefs denfe, and more rapidly with regard 

 to the negative than the pofitive. 



Hence Cit. Tremery deduces the general refult, that the 

 infulating property of non-conductors cannot be the fame for 

 both electricities. 



From this explanation, he thinks it eafy to reconcile th« 

 theory of two fluids with the few facts oppofed to it by hi s 

 adverfaries. 



* Or if one fingle pafs from one conductor to the other, the at* 

 traction or power of the receiving conductor will be very oblique t<* 

 the card at firft, and moft direct at laft ; whence the place of frac- 

 ture is inferred to be at the receiving or minus extremity. 



W.N. 



f Yet a negative point difcharges its electricity more eafily than 

 a pofitive. See Fig. 5, PI. VIII. 



W. N. 



