138 Dr. Ure on Gunpowders 



parts of potash are fully sufficient to dissolve out one of sul- 

 phur. When the above solution is thrown on a filter, and 

 washed first with a very dilute solution of potash boiling hot, 

 then with boiling water and afterwards dried, the carbon will 

 remain ; the weight of which deducted from that of the mixed 

 powder will shew the amount of sulphur. 



I have tried many other modes of estimating the sulphur in 

 gunpowder more directly, but with little satisfaction in the 

 results. When a platina capsule, containing gunpowder spread 

 on its bottom, is floated in oil heated to 400 Fahrenheit, a 

 brisk exhalation of sulphur fumes rises, but, at the end of 

 several hours, the loss does not amount to more than half the 

 sulphur present. 



The mixed residuum of charcoal and sulphur digested in hot 

 oil of turpentine gives up the sulphur readily ; but to separate 

 again the last portions of the oil from the charcoal or sulphur 

 is hardly possible. . . 



When gunpowder is digested with- chlorate of potash and 

 dilute muriatic acid," at a? moderate heat, in a retort, the sul- 

 phur is acidified ; but this process is disagreeable and slow, and 

 consumes much chlorate. The resulting sulphuric acid, being 

 tested by nitrate of baryta, indicates of course the quantity of 

 sulphur in the gunpowder. A curious fact occurred to me in 

 this experiment. After the sulphur and charcoal of the gun- 

 powder had been quite acidified, I poured some solution of the 

 baryta salt into the mixture, but no cloud of sulphate ensued. 

 On evaporating to dryness, however, and redissolving, the 

 nitrate of baryta became effective, and enabled me to estimate 

 the sulphuric acid generated ; which was of course 10 for every 

 4 of sulphur. 



The acidification of the sulphur by nitric or nitro-muriatic 

 acid is likewise a slow and unpleasant operation. 



By digesting gunpowder with potash water, so as to con- 

 vert its sulphur into a sulphuret, mixing this with nitre in 

 great excess, drying and igniting, I had hoped to convert the 

 sulphur readily into sulphuric acid. But on treating the fused 

 mass with dilute nitric acid, more or less sulphurous acid was 

 exhaled. This occurred even though chlorate of potash had 

 been mixed with the nitre, to aid the oxygenation. 



