MISCELLANEOUS. 327 



noes ; as it is well known that they always furnish 

 abundance of sulphur, and also metallic substances 



To produce Artificial Lightning. 



Provide a tin tube, that is much larger on one 

 side than the other, and in which there are se- 

 veral holes. Fill this tube with resin, in powder, 

 and when it is shook over the flame of a torch, it 

 will produce a sudden corruscation that strongly 

 represents a flash of lightning. This is the manner 

 in which lightning is produced at the theatres : it 

 is not the flame itself that is to be seen, but its 

 reflection only, as happens for the most part in 

 nature. 



In this manner also the flambeaux of the 

 furies on the stage are constructed, except that, 

 at the end of each of them, there is a match dipped 

 in spirits of wine ; by means of which it is only 

 necessary to shake them, and they will produce a 

 sudden and very considerable flame. 



Method of cutting Glass, by means of Heat. 



Take a common wine-glass, or any vessel you 

 want cut, and having heated a poker in the fire till 

 it is almost red hot, but not quite, apply it to the 

 part where you wish the crack to begin ; having 

 held it upon the part for about a minute, remove 

 the poker, and wet the place : the glass will imme- 

 diately crack. Having now begun the crack, you 

 may lead it in any direction, by merely drawing the 

 hot poker in the direction you want. This is ex- 

 tremely useful in many chemical experiments, 

 where you are in want of proper apparatus. 



Glass tubes may be easily cut with a file. 



