vol,. XVIII.l PHILOSOPHICAL TRANSACTIONS. 66g 



We further made an experiment in pleno, or after this manner : We put a 

 small quantity of the oil in a gallipot, and some of the spirit in an open glass, 

 and fixed a plate of copper upon the gallipot, so as to cover it pretty exactly, 

 and then set a weight upon the plate, and pulling a string, made the spirit to 

 mix with the oil, which at that instant blew up the cover, and threw off the 

 weight. But though in some respects it agrees with gunpowder, yet in others 

 there is a great disparity: for gunpowder will not be made to take fire, or make 

 any explosion in vacuo, both which this mixture performed with the same cele- 

 rity at it did in the air. Gunpowder is a composition of the most dry and 

 combustible materials we can put together ; whereas in our mixture of two 

 fluids, one of them is not easily made to burn by itself, and the other will ex- 

 tinguish common fire. Gunpowder requires actual fire to bring it to an accen- 

 sion ; whereas in this you have only two waters or liquors, both cold to the 

 touch, that produce fire and flame by the bare joining and mixing them to- 

 gether. 



On the extinction of the flame, produced as above, you will have remaining 

 a light and blackish substance, which will indeed vary both as to the bulk and 

 complexion, according to the difference of the oils. But in this they all agree, 

 viz. to leave behind a spongy and exceedingly light matter, and perfectly insipid. 

 Sometimes it swells up into a great protuberance, as large as a man's fist, above 

 the gallipot, and if you taste it, and macerate it in your mouth, you will find 

 it to be as tasteless as paper, or even paper when burnt to ashes. So that we 

 may safely conclude, that by this powerful mixture, a third solid body results, 

 absolutely differing from either of the two mentioned liquors ; and which makes 

 it the more remarkable, that both of these fluids, which have so great an im- 

 pression on the organs of smell, and a very great one on the organs of taste, 

 should in an instant be destroyed, and terminate in a dry insipid caput mortuum, 

 which will not melt in the air, nor be dissolved by water, nor other corrosive 

 menstruums, but remains as much a caput mortuum as a piece of paper, or a 

 rag burnt to ashes, if not much more. 



Mr. Molt, a most ingenious chemist, informs me, that spirit of wine would 

 give a flash of light with this compound spirit, but not burn; and he has ob- 

 served the same circumstance in his experiment, which I did formerly in the 

 year l683,* that if you put the spirit of wine to the nitre, you will have a great 

 effervescence immediately ensue; but if you invert the order, and put the spirit 

 of nitre on the spirit of wine, you will not have any ebullition for some time: 

 which circumstance is quite contrary to all the other experiments we have made 



* See Transactions, No 150.— Orig. 



