94 PHILOSOPHICAL TRANSACTIONS. [aNNO 1745. 



performed almost in a moment of time, it would have seemed to surpass all be- 

 lief. But about the end of both the years 1742 and 1743, Mr. H. experimented 

 something of the same kind himself. 



He had some conical glasses of water, with some of those glass images in 

 them, called Cartesian devils, which afforded several curious instances of sudden 

 freezing, particularly on being touched with something warm. 



1 . When the water had received a sufficient degree of cold, whether the glass 

 was then removed into a warm place, or was only taken in a warm hand, almost 

 the whole water would in. a moment be changed into ice: but more readily in 

 the former case than in the latter. 2. It made no difference whether the glass 

 was covered with a bladder or not; nor whether the bladder was pressed with the 

 fingers or not. Neither did it signify whether any Cartesian devil, or any other 

 such image, was in the glass or not; and if there was one, whether it kept at 

 the bottom of the glass, or rose to the top. 3. When there was an image in the 

 water, the freezing always began at some part of it, and diffused itself on all 

 sides. 



After M. du Fay had discovered by accident, that an electrified human body, 

 if touched by another not electrified, would emit sparks that pricked pretty 

 sharply, these experiments were repeated in the university of Leipsic; but instead 

 of the glass tube, used by Mr. Gray and M. du Fay, they employed a glass ball, 

 such as formerly was used by Mr. Hauksbee. On this occasion it was observed, 

 that electrified bodies, especially those of animals and metals, emitted sparks so 

 strong, as to set on fire, not only spirit of wine moderately warmed, but also, 

 other inflammable bodies, such as gunpowder, pitch, brimstone, and sealing-wax, 

 being first well heated. An iron tube turned, and suspended horizontally on 

 lines of blue silk, having one end as near as possible to the glass ball, to receive 

 its electricity, and the other end of it touched by a man standing on a cake of 

 pitch ; then the electrical force was so diffused through his whole body, that any 

 part of it would attract and repel alternately leaf gold, and other light bodies; 

 and either this man or the tube being touched by another person, emitted sparks 

 extremely pungent. Also when the man on the cake of pitch had a sword on, 

 sparks would spontaneously issue from the extremity of the sheath. When an- 

 other person held spirit of wine warmed, in a spoon, and the electrified man 

 brought his finger, or an iron key, or the point of a sword, near the surface of 

 the spirit, it immediately inflamed. Or when the electrified man held the spoon 

 with the spirit, and another person put his finger near it, the same effect ensued. 

 And when several persons, standing on pitch, held each others hands, or were 

 united by a cord, or an iron tube, &c. then the last would perform the same as 

 the first or second. 



Mr. Hollmann liaving observed, in Baker's Microscope made Easy, that Mr. 



