TRANSACTIONS OF THE SECTIONS. 41 



of these are simultaneous ; the ■way in which the others succeed each other cannot 

 be accuratel)' determined : at first, when a poi-tion of the carhon is burned, potassic 

 carbonate, carbonic oxide, nitrogen, and carbonic acid are produced. Simultane- 

 ously with this reaction another takes place — a portion of the saltpetre and the 

 whole or a portion of the sulphur form potassic sulphate and carbonic acid. The 

 action of still vmburnt carbon and of free sulphur on the potassic sulphate, in a suc- 

 ceeding stage of the combustion, causes the formation of potassic sulphide and hypo- 

 sulphite. On the ground of such considerations, the processes taking place dm-ing the 

 combustion of powder can be represented by equations. These, with other details, 

 will be published elsewhere. 



On the Manufacture of Sole-leather in Bristol. 

 Bu Spaeke Evans, Avonside Tannery. 



Very little notice is taken of the trade in city records, probably from the position 

 of the tanneries being outside the city boundaries. In 1816 there were nine tan- 

 neries, now there are thirteen. The trade was formerly much fettered by absurd 

 restrictions and excise laws. The leather made in this locality is of excellent 

 quality, from proximity to oak-woods and the length of time allowed in tanning. 



M'CuUock estimates the leather-trade as third in importance in the United 

 Kingdom, giving precedence only to wool and iron. 



The growth of commerce caused such a demand for leather that it would soon have 

 attained a fabulous value but for the introduction of South-American hides and 

 Turkish Valmiea. South- American hides were first imported to Castile in 1580 : total 

 shipment from South America in 1872 of dry and salted hides 3,121,758, the prodiice 

 of vast herds roaming over the pampas, which is estimated at 11 to 15 millions. 

 Hides obtained of cattle in a semi-wild state much thicker than from high-bred 

 animals. The loss occasioned by branding to prove ownership computed at 

 £300,000 yearly. 



The recent practice of pickling on the voyage strongly objected to, yet likely to 

 prove its own cure. 



Messrs. Conyers and PuUein have introduced a mode of suspending hides in lime, 

 thus unhairing in four days without heat. Neither cool-sweating process used in 

 America nor the sulphide of sodium or by charcoal used in Bristol. 



Bristol early adopted the system of rounding. Failure of all patent processes for 

 tanning. Rapid processes and new materials generally regarded with distrust, 

 twelve months being required to make thick leather both pliable and impermeable. 

 A considerable quantity of army leather supplied from this city, for which prize 

 medals have been awarded. The British troops are better shod than any other 

 soldiers in the world ; and Sir Garnet Wolseley says, " The regiment that can 

 march best in an army is the best in that army." 



Increased working of large tanneries in favoiuably situated districts, and disap- 

 pearance of small countiy yards. Five, for example, have been closed in Ash- 

 bm'ton, Devon. 



Kij) tanning. — Imports estimated at 7,000,000. Average amount of plaster adul- 

 teration on each kip one and a half pound. 



Principal tanning materials used in Bristol : — Oak-bark, Valonea, Myrobalan, 

 Mimosa, Terra Japonica, Divi-Divi, and recently hemlock extract. Valonea 

 having doubled itself in value, great need is felt for new materials, of which a few 

 have been introduced, but not in commercial quantities. 



Waste products. — Untanned portions of hide sold for sizing paper and manu- 

 facture of gelatine. Hair now largely used in manufacture of cheap clothino', 

 blankets, and imitation of seal skins. Spent tan burnt for its ashes ; lime-deposit 

 useful as a manure. 



Effect of Free Trade. — First American leather sent to England in 1814, quantity 

 1000 sides; in 1874, 1,159,854 sides, which pay no duty; while any English 

 leather shipped to America must pay an import duty of more than 30 per cent. 



Desirableness of importing live cattle from the River Plate, which may there be 

 bought at £5 per head — thus importing meat, hide, bones, hair, and hoofs without 

 waste. 



1875. 4 



