126 Dr. Ure on Gunpowders 



Z. On the Sulphur. 



The sulphur now imported into this country, from the vol- 

 canic districts of Sicily and Italy, for our manufactories of sul- 

 phuric acid, is much purer than the sulphur obtained by 

 artificial heat from any variety of pyrites, and may, therefore, 

 by simple processes, be rendered a fit constituent of the best 

 gunpowder. As it is not my purpose here to repeat what may 

 be found in common chemical compilations, I shall say nothing 

 of the sublimation of sulphur ; a process, moreover, much too 

 wasteful for the gunpowder-maker. 



Sulphur may be most easily analyzed even by the ma- 

 nufacturer himself; for I find it to be soluble in one- tenth 

 of its weight of boiling oil of turpentine, at 316 Fahrenheit, 

 forming a solution which remains clear at 180. As it cools 

 to the atmospheric temperature, beautiful crystalline needles 

 form, which may be washed sufficiently with cold alcohol, 

 or even tepid water. The usual impurities of the sulphur, 

 which are carbonate and sulphate of zinc, oxide and sulphuret 

 of iron, sulphuret of arsenic and silica, will remain unaffected 

 by the volatile oil ; and may be separately eliminated by the 

 curious, though such separation is of little practical importance. 



Two modes of refining sulphur for the gunpowder- works 

 have been employed ; the first is by fusion, the second by 

 distillation. Since this combustible solid becomes as limpid 

 as water at the temperature of about 230 Fahrenheit, a ready 

 mode offers of removing at once its denser and lighter impuri- 

 ties, by subsidence and skimming. But I may take the 

 liberty of observing that the French melting pot, as described 

 in the elaborate work of MM. Bottee and RifFault, is singu- 

 larly awkward, for the fire is kindled right under it, and plays 

 on its bottom. Now a pot for subsidence ought to be cold- 

 set ; that is, should have its bottom part imbedded in clay or 

 mortar for four or six inches up the side, and be exposed to 

 the circulating flame of the fire only round its middle zone. 

 This arrangement is adopted in many of our great chemical 

 works, and is found to be very advantageous. With such a 

 boiler, judiciously heated, I believe that crude sulphur might 

 be made remarkably pure; whereas by directing the heat 



