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firmly twilled in the middle at I : the other end of the wire I ham- 

 mered flat, and faftened it to a fmall wooden ball. 



Having thus prepared the tube, I filled it with fair rain water, 

 and inferted into it the brafs wire by the end H I K, having firfi: well 

 tallowed the leather bound round this end, and I prefied it fo forcibly 

 into the tube, that no particles of water could pals by it : indeed, 

 fo violent was the preflure, that in this experiment, I broke four of 

 my glafs tubes. 



This glafs tube being thus filled with water, that no air could be 

 feen at M, I prefled the inrtrumr nt L M, which I will call the pifton, 

 llowl}' into the tube, until the lower part of it, O N, at the extre- 

 mity N, came near to the oblique or curved part of the glafs. In 

 doing this, the water ilTued out of the aperture in the fmall tube D, 

 in a ftream like a fountain, until there was no water in the tube, 

 but from D E C B to N. 



I then held the fmall glafs tube from E to D, to the flame of 

 a candle, until the heat drove out the water from E to D, which 

 being done, I applied the aperture D to the flame, whereby the 

 glafs melted, and clofed the orifice. 



Having thus managed the glafs tube, that there was no air (as far 

 as appeared) between NBCED, unlefs from E to D, being one 

 fixth part of an inch, I poured a little water into the aperture A, 

 letting it run down and fettle upon the pillon at O, to the intent, 

 that if there fliould chance to be any aperture or uneven nefs in the 

 cavity of the glafs, water and not air might pafs by the inllrument 

 N O, when ufed as a fucker. 



After this, I gradually drew up the pifion or fucker out of the 

 tube, and, while I was doing it, I faw, that not only the tube from 

 E to C, immediately became empty of water, and was filled with 

 air, but the water in the larger tube was depreflcd from C towards 

 R, for the Ipace of three inches ; and, during this operation, many 

 bubbles of air arofe out of the water, and bubbled to the fur- 

 face, and ftill the inore when I lliook, or with a tap ftruck 



