Kingdom.] Class 2.—CHEMICAL AND PHARMACEUTICAL PRODUCTS. 189
South Gallery.
The same ores in process of decomposition, and in astate of complete decomposition. The insoluble portionof the decomposed ores mixed with alum schist in itsnatural state, after having been subjected to combustion.Muriate of potash, used in the alum manufacture. Manu-factured alum, once, twice, and thrice crystallized; orfinished alum. A miniature roaching tun, showing themode in which the finished alum is crystallized. Ironpyrites. Specimens of prussiates of potash.
[At the foot of the Campsie hills there occur two orthree beds of coal of the South Scotch coal-field, andsome beds of alum slate, which decompose on exposureto the air. The beds have been much disturbed, andoften exhibit intruded masses of trap.
In preparing the alum obtained in an impure statefrom the decomposition of the bituminous and pyritousschist, much careful management is necessary. Theadmixture of a certain quantity of muriate of potash inthese processes, renders the whole rather a mineral ma-nufacture than a simple preparation of raw material.—D. T. A.] _
14 May & Baker, Battersea , Surrey — Manufacturers.
Specimens of nitric acid. Crystals of nitrate of silver.Trinitrate of bismuth. Rough camphor, as imported.Refined camphor in refining glass; camphor, prepared forsale. Precipitated chalk. White precipitate of mercury.Corrosive sublimate. Crude calomel. Prepared calomel.Red precipitate of mercury. Turpith mineral. Ponder-ous magnesia. Acetate of potash; acetate of zinc. Oxideof zinc. Sulphate of zinc, and chlorate of potash.
[.Nitric Acid . —The aquafortis of commerce consists ofimpure nitric acid. It is obtained from the distillation ofconcentrated sulphuric acid mixed with nitrate of potashor soda. The commercial substance called Chilian, orPeruvian saltpetre, is nitrate of soda, and has largelybeen used lately in the preparation of this acid. Thisacid is of immense importance in the arts, chemistry, andmedicine.—R. E.]
15 Cook, Thomas Ainsley, Newcastle-upon-Tyne —
Manufacturer.
Crystallized carbonate of soda. Manufactured by theWalker Alkali Company.
16 Lindsay, G., Sunderland —Manufacturer.
Green vitriol, or copperas of commerce, a proto-sulphate
of iron, extensively used in dyeing silks, woollens, andcottons, making writing inks, Venetian red, &c. It ismanufactured from iron pyrites, procured from the coalmines, exposed to air and moisture; the excess of acidbeing saturated by digesting the lixivium with iron platesand turnings.
[By heating proto-sulphate of iron to redness, it is de-composed, sulphurous and sulphuric acids being evolved,and sesqui-oxide of iron (Venetian red, colcotliar, jewel-ler’s rouge) remaining.—W. D. L. R.]
17 Moberley, W., Mulgrave Alum Works, Landsend,
near Whitby —Producer and Manufacturer.
Raw alum shale, as cut from the cliff, showing em-bedded nodules of cement stone; the same after calci-nation. Alum meal, or alum as first crystallized. Halfa cask of finished alum.
Rough sulphate of magnesia, being the residuum ob-tained in the manufacture of alum, used for making refinedEpsom salts. Refined sulphate of magnesia, or Epsomsalts, purified by a new patent process.
Patent double salt of ammonia and magnesia, for amanure for top dressing.
Bones dissolved in sulphate of magnesia, for a manure.
[Alum is manufactured at Whitby , by the combustionof the schists of the upper lias, which contain a certain
quantity of iron pyrites and bituminous, or carbonaceousmatter. The temperature being properly regulated, andwater occasionally supplied, a double decompositiontakes place, producing sulphate of alumina and sulphateof iron, together with a portion of sulphate of magnesia,if any magnesia is present in the alum schist. A subse-quent separation of the ingredients takes place. Acertain quantity of the sulphate or muriate of potash isadded, and the alum is crystallized. Alum is a triplesalt consisting of a hydrated sulphate of alumina and pot-ash, soda, or ammonia; but a portion of the aluminais occasionally replaced by iron.—D. T. A.]
18 Pattinson, William Watson, Gateshead ,
Newcastle-upon-Tyne — Manufacturer.
Large mass of crystallized alum, or sulphate of aluminaand potash. Masses of pure sulphate of alumina, calledin commerce concentrated alum. Specimen of bi-carbo-nate of soda.—Manufactured at the Felling Chemicalworks.
[The alum of English commerce is obtained in largequantities from manufactories at Whitby, in Yorkshire .A horizontal bed of fuel, composed of brushwood or ofsmall coal, is first made, and upon it pieces of aluminousrock are piled. The fuel being kindled, the whole massslowly ignites. More rock is piled upon it, until, insome instances, a vast heap of inflamed material, 100 feethigh and 200 feet square, is raised, and continues to bumfor months. The aluminous schist being thus disinte-grated, and its chemical constitution changed, is lixiviated,the solution evaporated in large cisterns and purified,and sulphate of potash or ammonia is then added. Thealum thus formed is dissolved, and crystallized by pouringthe solution into casks made with moveable staves, calledlc rocheing casks.” On removing the staves, an apparentlysolid barrel of alum is exposed. This is pierced withan instrument near the bottom, when the uncrystal-lized solution runs out. The mass, broken into lumpsand dried, is the alum of commerce. The shipments ofalum from Whitby in 1841 amounted to 3,237 tons.Alum is employed in medicine, in chemistry, and in thearts. Its most important use is as a mordant for dyers.—R. E.] _
19 Richardson Brothers & Co., 17 St. Heleris Place,
and 11 East Street, City Road —Manufacturers.
Specimens of refined saltpetre or nitrate of potash,obtained chiefly from the East Indies, and shipped fromCalcutta . This substance is used in the manufacture ofgunpowder, oil of vitriol, aqua-fortis, and other chemicalproducts, and also in curing provisions.
[Saltpetre is distinguished as the special natural pro-duct of the surface soil of warm countries. India, Egypt ,Persia, Spain, and Italy , yield our chief supply. Itis obtained from the soil, on the surface of which itmakes its appearance like hoar, by lixiviation. The solu-tion is then filtered, evaporated, and crystallized. It isprincipally imported into Great Britain from Calcutta andMadras. The amount imported from the East Indies andCeylon in 1841 , was 261,552 cwts. Its uses in chemistry,medicine, and the arts are familiar.—R. E.]
20 Stevenson, William, Jarrow Chemical Works,
South Shields — Manufacturer.
Crystals of soda converted into bi-carbonate of soda byexposure to carbonic acid gas.___
21 Tulloch, A., Waltham Abbey— Producer.
Saltpetre, charcoal, and sulphur, used in the manufac-ture of gunpowder at the Royal Gunpowder Mills at Wal-tham Abbey.
[ 2 -]
[Official Illustrated Catalogue.]
P