CHEMICAL MANUFACTURES ON THE TYNE. 179 



matter of the soil, while, being constantly renovated, a supply of oxygen 

 is provided in a solid form, by this hydrated oxide of iron. 



Venetian Red. — The manufacture of this article has long been 

 carried on in this neighbourhood, and is noticed here as it is so closely 

 related to green copperas. It is made by calcining a mixture of cop- 

 peras and some native hydrated oxide of iron, chalk, and gypsum. 

 The calcined mass is levigated and dried. About 4,000 tons per annum are 

 manufactured on the Tyne, and the price varies from 41. 10s. to 51. per ton. 



Sulphate op Copper. — Thi9 salt was formerly produced by roasting 

 old copper in a reverberatory furnace, and then dissolving the oxide in 

 sulphuric acid, but it is now obtained in carrying out Longmaid's pro- 

 cess for decomposing common salt by means of cupreous pyrites. The 

 quantity made is about 100 tons per annum, which is all produced at 

 the works of Messrs. J. and W. Allen. 



Resin Size. — This article is manufactured according to a patent 

 obtained by Mr. W. S. Losh, and is intended to produce a size suitable 

 for paper-makers, and to supersede the old size in ordinary use, which 

 consists of alum, resin, and soda ash. Its manufacture has, however, 

 been only partially developed, and not more than 100 tons yearly is 

 produced ; but a new and cheap size, which can be prepared ready for 

 the use of the paper trade is, we think, a step in the right direction, and 

 the theory of the sizing of paper is a field still open to chemists. 



Lamp Black. — The manufacture of lamp black, we believe, is peculiar 

 to this locality, and it is produced from bituminous coals. These coals 

 are slowly burnt, at a dull heat, and with as small a supply of air as 

 possible. The smoke is conducted into brick chambers, into which a 

 jet of steam or water is passed to assist in the better formation of the 

 lamp black. The quantity made is about 1,200 tons annually. 



Grease. — This product is made to the extent of 2,800 tons annually. 

 It is chiefly produced from the distillation of resin, and in a locality like 

 Newcastle, surrounded by extensive collieries and works, the consump- 

 tion is considerable. Since the American war the price has been much 

 affected, and, we are told, has advanced from 8Z. or 91. per ton to 221. per 

 ton. 



Chemical Products op Gas Works.— The quantity of coal used 

 in the manufacture of gas on the three northern rivers, the Tyne, 

 Wear, and Tees, amounts to about 100,000 tons. 



THE PRODUCTS OBTAINED ARE AS FOLLOWS : — 



i, 000, 000 cubic feet of Gas 



... £113,000 



53, 000 tons of Coke 



... 10,000 



23,800 gallons of Crude Naptha 



2,800 



309,000 gallons of Creosote Oil 



1,250 



3,560 tons of Pitch 



3,130 



600 tons of Sulphate of Ammonia 



9,000 



Total 



£139,180 



