1792' on glafs drops. r^t 



ly let it drop into cold Witer, and there lie till it is 

 cold. If the metal be too hot when it is dropped in- 

 to the water, the busiuefi does not succeed, but the 

 drop frosts and cracks all over, and falls to pieces in- 

 the water ; and every one that does not crack in the- 

 water but lies in it whole until it is quite cold, is 

 5ur° to be good. There is a great nicety in hitting, 

 a due degree of heat in the metal, and the workmen, 

 who best know their businefs cannot promise, before- 

 hand, which fhall succeed ; but often two fail for one 

 that is right. Some of them frost over the surface- 

 without falling to pieces ;. and others break into 

 pieces before the red heat is quite over, and that 

 with a small noise j others break soon after the red 

 heat is over and make a great noise ; and some neither 

 break nor crack until they seem quite cold, and 

 hold together while they are in the water, but fly 

 to pieces when they are taken out of it ; some do this 

 on the instant, others an hour or two after ; and o- 

 thers will keep several days, nay weeks, and at last 

 fall to pieces witliout being touched^ 



" These drops, thus formed, are so hard, that they 

 •will bear smart blows with>a hammer without break- 

 ing ;• and' yet if you grind the surface, or break off" 

 the tip of the tail, they v^ill fhatter, with a loud re- 

 port, into powder; and, in an exhausted receiver, with 

 greater impetuosity than in the open air, and into a. 

 finer powder, exhibiting light when the experiment 

 is made in the dark.. But if the drops are grouni 

 with th ^ powder of emery a id oil, and annealed by 

 the fire, they will escape bieaking. This surprising 

 phenomenon is supposed to arise from hence, that 



