“Ever yours truly,
“Richard F. Burton, F.R.G.S.
“Alfred G. Lock, Esq.”
SECTION V.
Sulphur in Iceland. By C. Carter Blake, Doc. Sci., Hon. For. Sec. Lond. Anth. Soc. London: E. & F. N. Spon, 48 Charing Cross. 1873.
The fact that sulphur, one of the most useful substances known, and, in the words of Mr Crookes, “the mainstay of present industrial chemistry,” has been an article of commerce throughout all time, and that a ready market has always existed for it, is familiar to all. Like the famous electrum of the ancients, its origin has been comparatively unknown. We shall briefly consider the conditions under which sulphur is found; its geographical distribution over the face of the globe; the method of its preparation for the market, and the circumstances which may lead capitalists to seek for the productive mineral at a shorter distance from our own shores than the Mediterranean or Mexico.
Sulphur is a simple, inflammable, brittle substance, of which all the forms found native belong to the rhombic or trimetric system, and are more or less modified rhombic pyramids. These crystals could not be formed at temperatures approaching that of boiling water, or be exposed to such a temperature without alteration; crystals of native sulphur must therefore have been formed at ordinary temperatures. Sulphur does not occur anywhere in sufficient quantity to constitute a rock, but is widely disseminated throughout rocks of different ages, either implanted in crystals, in small beds, nests and nodules in a pulverulent condition, as a coating, as in some lavas, or as a cement of decomposed trachyte. Dr Sullivan has said:[178]
“In volcanic regions the deposition of sulphur may result from two causes: 1st, the action of oxygen on damp sulphide of hydrogen gas, or on solutions of the gas; and 2d, the mutual decomposition of sulphide of hydrogen, H2S, and sulphurous anhydride, S2O. If the former be in excess, water and sulphur appear to be formed; if the latter be in excess, pentathionic acid, H2S5O6, and water are formed; the pentathionic acid is gradually decomposed into sulphur and sulphuric acid, which produce sulphates. In connection with this reaction, it may be observed that several sulphates are associated with the sulphur found in districts where the sulphur is formed from gases escaping through fissures. Old craters having such active fissures called fumaroles, are termed solfaterras.”
So important an influence does the price of sulphur exercise upon the cost of production of bleached and printed cotton stuffs, soap, glass, and other valuable manufactures of this country,[179] that it was the express subject of a commercial treaty, and in 1838 the British Government took very decided steps to put an end to a monopoly attempted to be established in it by the Sicilian Government.
That the present supply of sulphur is inadequate to the demand is proved by its high price, by the use of pyrites as a substitute, and by the inquiries recently made by the British Government as to its existence in Mexico. That the already large demand for this important substance must increase is quite evident when we consider the purposes to which it is applied.
Gunpowder.—Sulphur enters into the composition of this important article in proportions ranging from 10 to 20 per cent., according to whether the powder is required for war, sporting, or blasting purposes.[180] When we consider the vast quantity required by the gigantic armaments now maintained in every civilised country, as well as by the numerous mining and engineering operations at present in existence throughout the world (in which it is indispensable for blasting), we can form some idea of the immense amount of sulphur annually consumed in the manufacture of gunpowder alone.