185
Class 2.—-CHEMICAL AND PHARMACEUTICAL PRODUCTS.
South Gallery.
1 Pontifex & "Woou, Shoe Lane, Fleet Street —Manufacturers.
A series of chemical and metallurgic products, illus-trating the different processes employed for the reductionof lead from its ores, and its subsequent conversion intowhite lead.
Specimens of various colours and pigments, employedby artists and paper-stainers; crystals of tartaric and citricacid, sulphate of copper, &c.
2 Melincrythan Chemical Company, Neath, Wales —Manufacturer.
Sugar of lead, or acetate of lead.
3 Button, Charles, 146 Tlolbom Bars —
Manufacturer.
Chemical products: — Acids — boracic, chromic, carba-zotic, gallic, pyrogallic, metngallic, phosphoric and glacialanhydrous, and uric.
Alum—pure ammonia—chrome—potash—and sodaalums.
Ammonia nitrate, benzoate, and oxalate; and bin-oxalate (impure), remarkable for the size of the crystals.
Arsenic iodide; barium chloride—oxide, and oxidehydrate; barytes nitrate; bismuth chromate and nitrate;cadmium chromate; calcium phosphuret; cerium oxideand oxalate; cobalt acetate, nitrate, phosphate, andchloride; copper protoxide and suboxide; glucina ironsulphuret; lead nitrate, pure; lead chromate, fused;manganese sulphate; mercury nitrate, bichromate, andbicyanide; nickel sulphate; phosphate of soda and ammo-nia ; potash, pure ; potash chromate, silicate, and bin-arseniate; potassium iodide, bromide, and fluoride; silvernitrate; soda, pure; soda, nitrate; strontia nitrate; tinbisulphuret; tungstic acid; tungstate of soda; bitung-state of ammonia; uranium nitrate and oxide; zinc chlorideand sulphate, pure; phosphorus; iodine, pure; andbromine, pure.
Elements.
Products, viz , PrussianBlue , from
Iodide ofPotassium from
50
50
Cyanogen
61
61
t .
Potassium
62
20-4
41-6
Iodine. . .
163-2
32-2
131-0
336-2
163-6
172-6
Thus the iron and cyanogen, with a portion of the pot-assium and iodine, form Prussian blue of an intensecolour, and perfectly soluble; and the remainder of thepotassium and iodine form iodide of potassium, which,unlike the purest that can be purchased, has no alkalinereaction, when dissolved, on turmeric paper.
The properties of this new Prussian blue make it valu-able as a writing fluid and a dye; and the pure iodide ofpotassium, produced by this new process, is found topossess advantages in the preparation of calotype paper.
In the preceding experiment water is not decomposed,and there is no formation of hydriodic acid; but iodineappears to play the part of oxygen, and imparts to thePrussian blue the same rich tone that is obtained from aper-salt of iron. Without excess of iodine, the preci-pitate is nearly white, but rapidly absorbs oxygen fromthe atmosphere, and is soluble.
4 Buckley, J., the Trustees of the late, Manchester —Manufacturers.
Crystal of copperas, or sulphate of iron.
[This substance is in reality an impure sulphate of iron.The copperas of commerce is obtained by exposing heapsof bisulphuret of iron, or iron pyrites, to moisture andair for a considerable period. The elementary con-stituents of the iron pyrites, sulphur and iron, are oxi-dized, and a sulphate of the protoxide of iron is obtained,which is washed out and crystallized. It is largely usedin the arts for dyeing, ink-making, and also in chemistryand medicine.—R. E.]
3a Reade, Rev. J. B., F.R.S., Stone Vicarage, Aylesbury—Inventor and Patentee.
Cyaniodide of iron, or soluble Prussian blue , andiodide of potassium free from alkaline reaction.
These products, the first of them being a new com-pound, are obtained by adding iodide of iron, with iodinein excess, to yellow prussiate of potash, the quantitiesbeing in proportion to the equivalents of the final pro-ducts. Prussian blue remains on the filter, and is per-fectly soluble when washed and dried; and pure iodide°f potassium, as a residuary product, is obtained byevaporating the colourless filtered liquor, fusing andcrystallizing.
Equivalent of Cyaniodide of Iron.
Iron. 7 .
. 196 .
. 30-8
Cyanogen.... 9 .
. 234 .
. 36-8
Potassium ... 2 .
. 80 .
. 12-6
Iodine. 1 .
. 126 .
. 19-8
Cyaniodide of iron . 1
. 636 .
. 100-0
Grains.
Hence, if we take prussiate ofIodine 1261
potash . .
145-0
Iron . 28 f * orm 10 dide of iron . .
154-0
Iodine in excess to be dissolved in iron .
37-2
336-2
We have, on the whole, the following elements and finalproducts:—
6 Wilson, John, Glasgow —Manufacturer.
Alum slate, raw, in the condition of bisulphuret ofiron and alumina; found resting on the top of the coal inthe mines. Three other specimens of the same slate,showing the progressive stages of decomposition.
Sample of the same slate calcined.
Tub of alum in the last stage of manufacture.
Crystals of alum. Large specimen of the same.
Bisulphuret of iron (iron pyrites).
Iron pyrites decomposed.
Sulphate of iron (copperas) obtained from the same ore.
Sulphate of ammonia obtained from ammoniacal water,one of the products of the distillation of coal.
Naphthaline , obtained from naphtha; rare, in conse-quence of its size and purity.
A group of the crystals of sulphate of iron is exhibitedin the engraving,- page 186.
7 Spence, Peter, Pendleton Alum Works, Manchester —Inventor and Manufacturer.
Iron pyrites.—Bisulphuret of iron, obtained in nodulesinterspersed in coal; its most general use is to furnishcopperas or sulphate of iron by spontaneous decompo-sition, when spread on the ground, on what are technicallycalled copperas beds.
Refuse pyrites, after being burned for the manufactureof sulphuric acid ; used for the patent manufacture ofcopperas, by digesting it with sulphuric acid diluted.
Copperas crystals.
Sulphate of protoxide of iron, manufactured by patentprocess.