Large deposits of alum occur close to the village of Bulladelah, 30 m.
It is said to yield well, and a quantity of the manufactured alum is sent to Sydney for local consumption.
The modern town in the immediate neighbourhood, still known as Fokia, was founded by the Genoese in 1421 on account of the rich alum mines in the neighbourhood.
Alum and blue vitriol (sulphate of copper) are manufactured from decomposed schists at Khetri in Shaikhawati.
P. Granville put into practice between Alum Bay in the Isle of Wight and the Needles lighthouse a method which depends upon conduction through sea water.
Early in 1898 permanent stations were established between Alum Bay and Bournemouth, a distance of 142 m., where successful results were obtained.
Later the Bournemouth station was removed to Poole Harbour, and the Alum Bay station to Niton in the Isle of Wight, the distance being thus increased to 30 m.
Jager has described coprolites from the alum-slate of Gaildorf in Wurttemberg; the fish-coprolites of Burdiehouse and of Newcastle-under-Lyme are of Carboniferous age.
Other minerals found here are graphite, alum, potter's clay and roofing-slate, and, besides, famous silvermines were worked at Iglau during the middle ages.
Industries include slate quarrying, shipbuilding, iron and brass foundries, alum, vitriol, manure, guano and tobacco works.
Salts of ammonium were also known; while alum was used as a mordant in dyeing.
Many substances were employed in ancient medicine: galena was the basis of a valuable Egyptian cosmetic and drug; the arsenic sulphides, realgar and orpiment, litharge, alum, saltpetre, iron rust were also used.
Among the Arabian and later alchemists we find attempts made to collate compounds by specific properties, and it is to these writers that we are mainly indebted for such terms as "alkali," " sal," &c. The mineral acids, hydrochloric, nitric and sulphuric acids, and also aqua regia (a mixture of hydrochloric and nitric acids) were discovered, and the vitriols, alum, saltpetre, sal-ammoniac, ammonium carbonate, silver nitrate (lunar caustic) became better known.
Alum, vitriol, sulphur and nitric acid, by distillation.
For example, episomorphs of white potash alum and violet chrome alum, of white magnesium sulphate and green nickel sulphate, and of many other pairs of salts, have been obtained.
8 shows the variation of refractive index of mixed crystals of potash alum and thallium alum with variation in composition.
K A1um=z00% K Alum= o/, Tl Alum= o% Tl Alum_ zoo FIG.
In ancient times the alum of Melos was reckoned next to that of Egypt (Pliny xxxv.
The cups when full are poured into a larger vessel, and solution of alum is added to coagulate the latex.
In order to make spongy or porous rubber, some material is incorporated which will give off gas or vapour at the vulcanizing temperature, - such as carbonate of ammonia, crystallized alum, and finely ground damp sawdust.
ALUM, in chemistry, a term given to the crystallized double sulphates of the typical formula M 2 SO 4 ï¿½ MP' ï¿½(S04) 324H20, where M.
Potash alum is the common alum of commerce, although both soda alum and ammonium alum are manufactured.
The presence of sulphuric acid in potash alum was known to the alchemists.
He also showed that crystals of alum cannot be obtained by dissolving alumina in sulphuric acid and evaporating the solutions, but when a solution of potash or ammonia is dropped into this liquid, it immediately deposits perfect crystals of alum (Sur la regeneration de l'alun, Marggraf's Opusc. ii.
Knowing that alum cannot be obtained in crystals without the addition of potash, he began to suspect that this alkali constituted an essential ingredient in the salt, and in 1797 he published a dissertation demonstrating that alum is a double salt, composed of sulphuric acid, alumina and potash (Annales de chimie, xxii.
Chaptal published the analysis of four different kinds of alum, namely, Roman alum, Levant alum, British alum and alum manufactured by himself.
The word alumen, which we translate alum, occurs in Pliny's Natural History.
This property seems to characterize a solution of iron sulphate in water; a solution of ordinary (potash) alum would possess no such property.
Pliny says that there is another kind of alum which the Greeks call schistos.
From the name schistos, and the mode of formation, there can be little doubt that this species was the salt which forms spontaneously on certain slaty minerals, as alum slate and bituminous shale, and which consists chiefly of the sulphates of iron and aluminium.
The alumen of the ancients, then, was not the same with the alum of the moderns.
As alum and green vitriol were applied to a variety of substances in common, and as both are distinguished by a sweetish and astringent taste, writers, even after the discovery of alum, do not seem to have discriminated the two salts accurately from each other.
In the writings of the alchemists we find the words misy, sory, chalcanthum applied to alum as well as to iron sulphate; and the name atramentum sutorium, which ought to belong, one would suppose, exclusively to green vitriol, applied indifferently to both.
Various minerals are employed in the manufacture of alum, the most important being alunite or alum-stone, alum schist, bauxite and cryolite.
In order to obtain alum from alunite, it is calcined and then exposed to the action of air for a considerable time.
This powder is then lixiviated with hot water, the liquor decanted, and the alum allowed to crystallize.
The alum schists employed in the manufacture of alum are mixtures of iron pyrites, aluminium silicate and various bituminous substances, and are found in upper Bavaria, Bohemia, Belgium and Scotland.
It is now allowed to stand for some time, decanted from any sediment, and finally mixed with the calculated quantity of potassium sulphate (or if ammonium alum is required, with ammonium sulphate), well agitated, and the alum is thrown down as a finely-divided precipitate of alum meal.
In the preparation of alum from clays or from bauxite, the material is gently calcined, then mixed with sulphuric acid and heated gradually to boiling; it is allowed to stand for some time, the clear solution drawn off and mixed with acid potassium sulphate and allowed to crystallize.
When cryolite is used for the preparation of alum, it is mixed with calcium carbonate and heated.
Potash alum, K 2 SO 4 ï¿½Al 2 (SO 4)aï¿½24H 2 O, crystallizes in regular octahedra and is very soluble in water.
"Neutral alum" is obtained by the addition of as much sodium carbonate to a solution of alum as will begin to cause the separation of alumina; it is much used in mordanting.
Alum finds application as a mordant, in the preparation of lakes for sizing hand-made paper and in the clarifying of turbid liquids.
Sodium alum, Na 2 SO 4 ï¿½Al 2 (S04) 3 ï¿½24H 2 O, occurs in nature as the mineral mendozite.
In the preparation of this salt, it is preferable to mix the component solutions in the cold, and to evaporate them at a temperature not exceeding 60° C. ioo parts of water dissolve iio parts of sodium alum at o° C. (W.
Chrome alum, K 2 SO 4 ï¿½Cr 2 (SO 4) 3.24H 2 O, appears chiefly as a by-product in the manufacture of alizarin, and as a product of the reaction in bichromate batteries.
The solubility of the various alums in water varies greatly, sodium alum being readily soluble in water, whilst caesium and rubidium alums are only sparingly soluble.
Its chief mineral products are coal, nitre, sulphur, alum, soda, saltpetre, gypsum, porcelain-earth, pipe-clay, asphalt, petroleum, marble and ores of gold, silver, mercury, copper, iron, lead, zinc, antimony, cobalt and arsenic. The principal mining regions are Zsepes-Giimor in Upper Hungary, the Kremnitz-Schemnitz district, the Nagybanya district, the Transylvanian deposits and the Banat.
One part of cream of tartar, two of alum and two of common salt are dissolved in boiling water, and the solution is boiled with granulated metallic tin (or, better, mixed with a little stannous chloride) to produce a tin solution; and into this the articles are put at a boiling heat.
Mineral waters (with magnesia, soda-lithia and alum) issue from several springs, some at a temperature as high as 106° F., and are used both for drinking and for bathing.