( 247 ) 



in order to give a better idea of the manner of making my ob- 

 fcrvations on this fubjedl, I will explain how I prepared the fecond 

 and Imallell glafs tube which I ufed. 



I took a glafs tube, of the length and fize reprefented at ^^g". 2, 

 A B, and by the help of a brafs pipe, which goldfmiths and other 

 artificers ufe to folder fmall pieces of work, which they call a blow- 

 pipe, and by applying with it the flame of a candle I blew at the end 

 of it the fphere or glafs globule, fig. 3, FDE. 



When this fphere and the whole glafs was cooled, I dropped in- 

 to the opening, C, the particle of the before mentioned fubftance, 

 called natural light, which relied at the place E : I then took the 

 fphere between my fingers, that when I fhould again approach the 

 tube to the fire, there might the lefs heat reach to the fphere, then, 

 directing a llream of fire to the tube, at G, until the glafs was hot 

 enough to be extended, I gave it the figure fhewn at fig. 4, H I K L. 

 I then broke the glafs at the llender part, H, and the tube then was 

 of the Ihape fhewn at fig. 5, M N O P, and when the glafs was again 

 cool, I brought the orifice, M, to the flame of the blow-pipe, 

 whereby the glafs immediately melted, and the orifice was doled. 

 This glafs having remained clofed up for lb long a time as I have men- 

 tioned, I broke off a fmall piece at M, caufing an aperture about 

 the fize of a pin, and from which the air rulhed out with lb much 

 force as to produce fomething of a noife. I then immediately ob- 

 ferved the fubfiance in the glafs, and faw the globules driven from 

 it in as great numbers as if it had been but newly put into the glafs. 

 I examined it feveral times the fame day, and conllantiy faw the 

 expelled matter tending downwards, as I have before dcfcribed. 



The following day the matter was fo diminifiied that two fmall 

 cavities were formed in the middle of it, and the moifture was fo 

 much increafed that the matter fwam in it. In the evening of that 

 day two third parts of the folid fubilance were wafted : I then took 

 the piece out of the water, and faw the globules expelled from it 

 as large as ever. 



