( 36o ) 



is confumed in the cupel, its volume gra« 

 dually diminlnifhed, until in three minutes 

 it was entirely evaporated, without emit- 

 ting any apparent fume. In another expe- 

 riment the vitreous matter was poured up- 

 on a table, and made to flow, before the 

 water was entirely evaporated : no detona- 

 tion, however, followed. 



The convenience of accefs to a glafs- fur- 

 nace incited me to repeat thefe eafy experi- 

 ments, v.'hich have not, to my knowledge, 

 been verified by any other perfon. Before 

 1 proceeded to make them, I fpoke to one 

 of the workmen on the fubjedt, whom I 

 found fo well acquainted with the fad: that 

 he offered to pour as much water on melted 

 glafs' as I pleafed, aifuring me that not the 

 fmallefc ill effeft was to be apprehended. I 

 perceived, therefore, that this was one of 

 thofe phenomena which are publifhed to 

 the world as new, and which, in fad:, are 

 fo to the learned, but have been long well 

 known to many of the vulgar, 



I becfaa 



