180 COMPOSITION AND ANALYSIS OF GUNPOWDER. 



it on a piece of polished copper, I heated the copper by holding it 

 over the flame of a candle ; the gun. powder soon sent forth a sul. 

 phureous vapour ; and when it had been dried so long that no more 

 fume or smell could be distinguished, the remainder weighed nine, 

 teen grains, the loss amounting to five grains. The remainder did 

 wot explode by a spark like gunpowder, but like a mixture of salt, 

 pt-tre and charcoal, and it really was nothing else, all the sulphur 

 having been dissipated. Gunpowder was formerly dried by being 

 exposed to the heat of the sun, and this method is still in use in 

 France, f and in some other countries ; afterwards a way was in- 

 Tented of exposing it to a heat equal to that of boiling water; at 

 present it is most generally in England dried in stoves, heated by 

 great iron pots ; with any tolerable caution no danger of explosion 

 need be apprehended from this method. All the watery parts of 

 the gunpowder may be evaporated by a degree of heat greatly less 

 than that in which gunpowder explodes ; that degree haying been 

 ascertained by some late experiments, to be about the 600th degree 

 on Fahrenheit's scale, in which the heat of boiling water is fixed at 

 2 1 2. There is more danger of evaporating a portion of the sulphur 

 in this way of drying gunpowder, than when it is dried by exposure 

 to the sun. 



The necessity of freeing gunpowder from all its moisture, is 

 obvious from the following experiment, which was made some years 

 ago before the Royal Society. A quantity of gunpowder was taken 

 out of a barrel, and dried with a heat equal to that in which water 

 boils ; a piece of ordnance was charged with a certain weight of 

 this dried powder, and the distance to which it threw a ball was 

 marked. The same piece was charged with an equal weight of the 

 same kind of powder, taken out of the same barrel, but not dried, 

 and it threw an equal ball only to one half the distance. This 

 effect of moisture is so sensible, that some officers have affirmed, 

 that they have seen barrels of gunpowder which was good in the 

 morning, but which became (by attracting, probably, the humidity 

 of the air) good for nothing in the evening*. In order to keep the 

 powder dry, by preventing the access of the air, it has been pro. 

 posed to line the barrels with tin foil, or with thin sheets of lead, 

 after the manner in which tea boxes are lined f. Would it not be 



* qu'il avoit vu, dans les guerrcs d'ltalic, quelquc barrels dc poudre qui 

 toit bonne IP matin, etqui nc valoit rien le soir. Hist. Natt de 1'Espagne, p.82. 

 Hint Nat.de I'Espagne. 



