VdL. XXV.J PHILOSOPHICAL TRANSACTIONS. 325 



flying towards the tube, even at Q or 10 inches distance; and it seemed that the 

 hotter the tube was made by rubbing, the farther it would attract,* but that 

 it would do so to any degree of heat, I dare not determine. And it was further 

 observable, that sometimes the bodies attracted would adhere to the tube, and 

 there remain quiet: sometimes would be thrown violently from it to a con- 

 siderable distance: sometimes in their motions towards the glass, and sometimes 

 even touching it, they would suddenly be repelled back to the distance of 4 or 

 5 inches, repeating the same several times with great velocity in a very sur- 

 prising manner. Sometimes the bodies would move but slowly towards the 

 tube, sometimes remain a small time suspended between the glass and the 

 table on which the brass-leaf was laid; and sometimes seem to slide along the 

 sides of the glass without touching it. All which phgenomena, I have observed 

 several times; yet the force and vigour of the effluvium is sometimes less than 

 it is at other times. The reason of which seems to proceed from the difl^erent 

 temperatures of the air at the time the experiments are made; for when it 

 happens that abundance of humid particles are swimming in the air, it is easy 

 to believe, that the resistance of such particles may greatly impede the force 

 and extent of the effluvia: or they may suddenly condense on the warm tube, 

 and thereby hinder or choke the passage of the effluvia; for I find moistness 

 at all times an utter enemy to attempts of this nature: besides, the quality of 

 the effluvia seems to be such, that I could not, in an experiment lately made, 

 with all my endeavours, cause them to affect one of the forementioned bodies 

 through a piece of fine muslin, though it was held very near the tube, and 

 yet at the same time they would attract or give motion to the same body at 3 

 or 4 times that distance, if the muslin was not interposed. Moreover, I know 

 not also, but the coldness of the air at the same time may concur; for when 

 this experiment was first made, it was summer time, and dry weather; and 

 then it seemed to succeed rather better than it has done of late. But to pro- 

 ceed: when the glass became hottest by the greatest attrition, it then emitted 

 such a quantity of effluvia, as not only to produce the effects beforementioned 

 with seemingly greater vigour, but being nearly applied to the face, or any 

 tender part, it might be sensibly felt, as if the part was pushed with the points 

 of a considerable number of weak hairs. Considering the vigorous action of 

 the effluvium, I attempted to discover the figure of its motion, by approaching 



* Mr. Hauksbee here erroneously thinks that the attraction was owing to the tube's heat, instead 

 of to the friction only: for if the tube be only heated, as at the fire for instance, though ever so 

 much, without rubbing it, there will be no attraction. But this, and several other phaenomena in 

 this paper, which surprized Mr. Hauksbee here in the infant state of electricity, are circumstances 

 that are now easy and familiar to every person. 



