l$t Experiments on Ele&ricity 



times. I next made the electrometer diverge P. with an ex. 

 cited glafs-tube, and while it was divergent dropped a hot 

 cinder into the water : it immediately clofed, and opened 

 again N. The electrometer was then made N. with exeited 

 wax, and a cinder dropped into the water made the electro^ 

 meter open wider, and firike the fide of the bottle. 



3. I made fourteen fimilar trials with coals of burnt wood, 

 but could not find that any electricity was produced. 



3. In fixteen trials with tobacco-pipe the electrometer dU 

 verged N. eleven times, and five times it did not diverge at 

 all. In five out of the eleven, after the electrometer had dU 

 verged, it clofed again without touching the fides of the 

 bottle; but not fo much as to lofe all its divergence. 



4. In twenty-four trials with common white marble, the 

 electrometer diverged P. twelve times, and ten times the gold 

 leaf beat the fides of the bottle fo violently, that I could not 

 determine which ftate was produced ; (but, becaufe it was P. 

 in all thofe when it could be determined, I fuppofe it was fo 

 in thofe that could not) and twice it did not diverge at all : the 

 pieces in thefe two were very fmall. 



5. In twelve trials with mother of pearl, (fuh as common 

 pearl buttons are made of) the electrometer diverged P. 

 level) times. Three times I could not determine for the 

 violent beating of the gold-leaf againft the fides of the bottle; 

 and twice, when the pieces were very fmall and not very hot, 

 the electrometer became {lightly N. It is probable there 

 were foine fmall fragments of cinder thrown into the water 

 with the pearl ; for it was heated in a common fire, and 

 taken out with a fmall pair of tongs. 



6. In eight trials with common white coral, the electro- 

 meter diverged P. every time. 



7. n fix trials with oyfter^mells, the electrometer diverged 

 P. five times, and once it did not diverge at all: the piece 

 was not hot enough to raife much vapour. 



8. 1 made thirty-one trials with periwinkle-fhpUs ; and in 

 the firft feventeen trials the electrometer diverged P. fix times, 

 five times N., and three times it did not diverge at all ; and 

 twice it diverged and clofed again directly, before I could 

 determine which Rate was produced. In the other fourteen 

 trials it diverged P. every time. It is to be obferved, t,hat 

 the (hells ufed in the firlt feventeen trials were as they were 

 when the fiuY was boiled and failed in them; they were 

 therefore fpul with fait, &c, and alfo had their outfide 

 fkins on : hut in the fourteen laft trials the fhells were fuch 

 as had been burnt, and thrown into water while red- 

 hot, hefore they were made hot for the experiment, and by 



this 



