274 PHILOSOPHICAL TRANSACTIONS. [aNNO 1705. 



nor could it be revived again without a new one. In this experiment it was 

 sometimes observable, that the glass, when taken out after a violent attrition, 

 would be so hot as not to be held in the naked hand without a sensible offence. 

 That the woollen on which it rubbed would not only appear discoloured, but 

 sometimes perfectly burnt through. Sometimes a light would be carried quite 

 round the glass globe, so making a continued circle of it, during its motion, 

 notwithstanding it touched the woollen in no more parts than in the former 

 experiments. At other times, a perfect halo would appear around the stagnant 

 light ; which seems to proceed from some few drops of water, that will some- 

 times insinuate by the spindle, through the box on the upper brass plate, 

 where water is always kept, to prevent the entrance of air. This water de- 

 scending by the spindle, till it reached some more extensive part, would there, 

 by the violence of the motion, be thrown all about the receiver in small drops, 

 some of which were likely to fall on the woollen, where being heated by the 

 motion of the glass, evaporated, appearing like a halo around the light; for 

 since I have made a contrivance, to prevent the waters scattering, no such 

 appearance has happened. 



Sometimes I have observed the light to break from the agitated glass, in as 

 strange a form as lightning : particularly, when I used some list of cloth, that 

 had been drenched in spirit of wine, which was fastened to one arm of the 

 brass spring, on the other of which was tied some of the same list, that had 

 been steeped in water impregnated with salt-petre ; but both the pieces of list 

 were very well dried before I made use of them. 



At another time I made use of two flat shells of oysters well dried, instead of 

 the woollen, for the attrition of the glass, each arm of the brass spring having 

 one fixed to it. On the usual motion given the glass in vacuo, a light ap- 

 peared, resembling^ fierce flaming spark, just on the spot where the glass and 

 shells touched. The light seemed not to extend itself, but was comprized 

 in a small compass. I tried next what would ensue on the attrition of 

 woollen on the shells in vacuo. The success was, that there was a light pro- 

 duced, but it appeared very dim and gloomy, at best like a faint halo. 



In order to try in what degree the woollen might contribute to the phaeno- 

 mena of the foregoing experiments, I took some of the list formerly mentioned, 

 and bound it about the edge of a wooden wheel, I had caused to be turned for 

 that purpose; the wheel, with its wooden edge, I fastened on the spindle, as 

 usual, and upon the brass spring was used the same gartering, as in the first 

 experiment. These being put together, as in all the other experiments, and 

 the receiver exhausted, the large wheel was turned, and on the attrition of the 

 woollens, a small glimmering light succeeded ; but the continuance of the 



