130 CHEMICAL MANUFACTURES ON THE TYNE. 



The practical difficulty in burning this ore, namely its great fusibility 

 at the point where the combustion of the sulphur gives rise to consider- 

 able heat, has been overcome by the adoption of kilns, first used in 

 Lancashire, in which the area of the surface is large in proportion to the 

 weight of the charged pyrites. The use of cupreous pyrites has led to 

 the introduction of the manufacture of copper on the Tyne, which will 

 this ye.ir amount to between 700 and 800 tons. The ordinary process 

 of smelting is employed — but the moist method is also being tried, the 

 advantage being that, by this method, all the ingredients of the mineral 

 are utilised, the oxide of iron making an ore of similar quality to hema- 

 tite. The smelting process, however, is still preferred in the large 

 manufactories. In 1860 several cargoes of an ore containing free 

 sulphur imbedded in gypsum were imported from the Island of Milo, in 

 the Archipelago. From the small quantity of sulphur contained in it (19 

 up to 24 per cent.) there was great difficulty found in burning it, except 

 the large masses. Subjoined is an analysis of one parcel of it : — Siilphur 

 24-00; gypsum, 62-20; sand, &c, 6 00; water, 7'00. Still more 

 recently, Professor Ansted has discovered a deposit of free sulphur in 

 Corfu, of which he has been kind enough to forward a sample, but we 

 believe it has not been used in commerce. When sulphuric acid is 

 wanted quite free from arsenic, Sicilian sulphur must be used. So 

 largely has pyrites displaced sulphur in the production of sulphuric acid, 

 that in 1862 only 2,030 tons of sulphur were consumed, against 72,800 tons 

 of pyrites ; and, reckoning the above quantity of sidphur as equivalent to 

 4,500 tons it appears that 77,300 tons of pyrites are annually used for the 

 manufacture of sulphuric acid, along with 2,500 tons of nitrate of soda. 

 Assuming a produce of 120 per cent, on the pyrites, this is equal to a 

 production of 92,760 tons of sulphuric acid, calculated as concentrated. 

 This quantity of sulphuric acid is nearly all consumed where it is made, 

 for the manufacture of other chemicals, such as soda and manures, the 

 quantity sold being 6,440 tons, but this might be more correctly described 

 as consumed in other works, for the quantity sent to a distance is very 

 small. Four-fifths of the sulphuric acid is used for the decomposition of 

 common salt. 



Salt and the Alkali Trade — The ordinary Cheshire salt is 

 almost exclusively used for the manufacture of alkali, the exception 

 being in one manufactory, where the waste heat of coke ovens is utilised 

 in evaporating the liquors formed by dissolving rock salt. The anciently 

 extensive salt works of Shields are now represented only by one or two 

 comparatively small manufactories of salt, intended entirely for domestic 

 use. Nearly all the salt used in the alkali works is carried by canal to 

 Hull, Goole, or Grimsby, whence it is brought to the Tyne at a nominal 

 freight, generally by foreign vessels, that take it as ballast when coming 

 to the Tyne for an outward cargo of coals. This is the only practical 

 result of the repeal of that portion of the navigation laws that pre- 

 vented foreign ships carrying cargoes coastwise. The annual decompo- 



