to ®f tfre tj&tmnM ®ti$iw 



quire to be as well wip'd as chafd* 

 and even good ones will have their 

 Operation promoted by the fame 

 means. And this is very agreeable 

 to our Do&rtne^ fince TerGotr, be- 

 tides that it is 3 as I have fometimes 

 manifeftly known it , a kind or de- 

 gree of Attrition^ frees the Surface 

 from thofe adherences that might 

 choak the pores of the Amber y or 

 at leaft hinder the emanation of the 

 fteamsto be fofree and copious as o- 

 therwife it would be. 



4. Tis likewife obfervM^ That 

 whereas the Magnetical Steams are 

 fo fubtile , that they penetrate and 

 perform their Operation through 

 all kind of Mediums hitherto known 

 to us 5 Elettricai Steams are like 

 thofe of fome odoriferous Bodies^ 

 ealily check d in their progrefs^ fince 

 'tis affirmed by Learned Writers* who 

 fay they fpeak upon particular Trials 

 that the interpofition of the fineft 

 Linnen or Sarfnet is fufficient to hin- 

 der all the Operation of excited 

 Amber upon a Straw or Feather 



placd 



