Sulphur

of the sulphur present is obtained in a successful operation. The processes of extracting sulphur by fusion by superheated steam is used to considerable extent in Louisiana. Distillation, and extraction by a solvent such as carbon disulphide, are also carried on, though only to a comparatively small extent. Sulphur is also obtained by heating pyrites, though the product is impure and the yield very poor; most of the sulphur from sulphides goes to make sulphuric acid. A portion of this sulphur is sometimes recovered from the waste by the Leblanc alkali process. (See SODIUM.) Crude sulphur is purified by distillation from iron retorts into brickwork chambers, in which, when cold, the sulphur vapor condenses as a fine powder known as 'flowers of sulphur'; but as the temperature rises it is deposited in the liquid form. The latter is cast into thick sticks for sale as 'roll sulphur.'

Common sulphur is a pale yellow, odorless, brittle solid, which is insoluble in water but readily dissolves in solvents such as carbon disulphide, from which it crystallizes in rhombic octahedra. It is as a brittle opaque aggregate of minute crystals of the octahedral variety that sulphur usually appears in the market, and it is characterized by its very poor conducting power for electricity and heat. Octahedral sulphur melts at 115° C., and prismatic at 120° c., the liquid when near the melting-point being mobile and of golden yellow color. On raising the temperature the liquid becomes dark red and increases in viscosity, so that at 250° c. the vessel containing it can be inverted without the sulphur running out. On still further raising the temperature, the sulphur becomes darker and liquid again, boiling at 446° c. to a brownish-red gas. If the sulphur is suddenly chilled, as by pouring into cold water, it passes into a third allotropic variety known as plastic sulphur, which is soft and springy like india-rubber. This form is insoluble in carbon disulphide, and changes in a few days into the brittle octahedral form. Flowers of sulphur, and 'milk of sulphur,' produced by precipitating solutions of polysulphides with acids, are probably not distinct forms, but only finely divided octahedral sulphur.

Chemically, sulphur enters into reaction easily; thus when heated it catches fire at a comparatively low temperature and burns in aír or oxygen with a lilac flame to form sharp-smelling and suffocating fumes of sulphur dioxide. Metals, such as iron, burn brightly when heated in sulphur vapor;

533

while reaction with non-metals, such as iodine, carbon, and hydrogen, also readily takes place, the corresponding sulphides being formed. Boiled with solutions of potassium or calcium hydroxides, complex mixtures, chiefly composed of polysulphides, are formed. Sulphur is chiefly employed for the production of sulphur dioxide, for fumigation, for the manufacture of sulphuric acid, sulphites, etc., and as a component of gunpowder and pyrotechnic mixtures. It is also an excellent insulator, and when applied molten is used as a cement. In medicine it is used externally as a parasiticide for the cure of scabies, and internally as a mild, though somewhat unpleasant, aperient.

Of the simple compounds of sulphur the following are among the more important:-Hydrogen sulphide or sulphuretted hydrogen, HS, is a gas that occurs naturally in some mineral springs and emanations from the soil, and is formed whenever organic matter containing sulphur, such as the albumin of eggs, undergoes decay. It is commonly prepared by the action of dilute hydrochloric acid on ferrous sulphide, 2HCl + FeS = FeCl2 + HS, numerous special forms of apparatus having been devised for the purpose, but for general use Kipp's apparatus serves quite satisfactorily. Hydrogen sulphide is a colorless gas that smells like rotten eggs, and is poisonous. It is slightly soluble in water, liquefies at 61.5° C., and freezes at -82° c. to an ice-like solid. When set on fire it burns in air with a lilac flame, producing water and sulphur dioxide or sulphur according to the quantity of air supplied. Hydrogen sulphide is faintly acid to litmus paper, and forms a series of salts (the sulphides) which are useful in the laboratory as the means of detecting and estimating metallic radicals. The formation of lead sulphide is used as a test for hydrogen sulphide, and is the cause of blackening of paints containing lead compounds; while the formation of sulphide of calcium by the action of slaked lime on the gas is commonly employed to remove hydrogen sulphide from gases containing it. Another important property of hydrogen sulphide is its reducing action-for example, ferric salts are reduced to ferrous salts, its behavior in this way being made use of commercially to reduce nitro-derivatives to anilines. Hydrogen sulphide is also employed therapeutically, the efficacy of certain mineral waters in the treatment of rheumatism, skin diseases, etc., being probably due to the small quantity of

Sulphur

hydrogen sulphide dissolved in them.

Sulphur dioxide, sulphurous anhydride, SO2, is a gas that is given off from some volcanoes, and is produced whenever sulphur or its compounds are burned in air. This process, in which either sulphur itself or pyrites, FeS2, is burned, is the method by which sulphur dioxide is obtained commercially, chiefly for the manufacture of sulphuric acid, S+O, SO2, and 4FeS2+1102= 2Fe2O3+8SO2. On a small scale sulphur dioxide can be conveniently obtained by heating copper and concentrated sulphuric acid, when a reaction, in the main represented by the equation Cu + 2H2SO, = ČuSO4 +2H2O+SO2, takes place, or by acting on sodium sulphite with sulphuric acid, Na2SO3+2H2SO1 =2NaHSO4+H2O+SO2. Sul

phur dioxide is a colorless gas, with a very sharp, suffocating smell. It is very soluble in water, one volume of the latter dissolving fifty volumes of the gas at ordinary temperatures. Sulphur dioxide is easily liquefied, at a temperature of -10° c., under atmospheric pressure, and at 15° c. under a pressure of 2.7 atmospheres. The liquid, which is colorless, is readily obtainable commercially, compressed in soda-water 'siphons.' Sulphur dioxide does not burn in air or with ordinary combustibles, though metals such as potassium burn brightly in it, forming their sulphides and oxides. The solution of sulphur dioxide in water reddens litmus, forming the unstable diabasic sulphurous acid from which a class of salts (the sulphites) is derived. Sulphur dioxide in the presence of water has powerful reducing properties, converting halogens to hydrogen halides, etc., and destroying various coloring matters. This action is made use of to bleach straw and wool. The gas has also a powerful antiseptic action; one of the commonest methods of disinfection is to burn sulphur in the room and shut it up closely for some hours. Sulphur dioxide is further employed as an 'antichlor' to remove the last traces of chlorine from materials bleached with the latter, in the curing of hops, etc.

Sulphur trioxide, sulphuric anhydride, SO3, is formed to a small extent when sulphur is burned in air. It is prepared either by heating certain sulphates, Fe2(SO4)3 = Fe2O3+2SO3, or by passing a mixture of sulphur dioxide and oxygen over a heated catalytic agent, such as platinized asbestos. Sulphur trioxide is a colorless, crystalline solid, that melts at 15 c., and readily volatilizes to a fuming, choking gas,

reacts

one form of the crystals resembles asbestos, subliming without passing through the liquid state. Sulphur trioxide violently with water to form sulphuric acid, and is employed technically in the preparation of carbon compounds.

Production.-Sicily has been the chief source of native sulphur. But of recent years the extensive deposits of Louisiana have entered as important rivals in the world production. Beginning with 1903 Louisiana sulphur entered the European market. Sicily produces about 500,000 long tons of sulphur per year.

Sulphur Dioxide. See SULPHUR and SULPHUROUS ACID.

Sulphuretted Hydrogen. See SULPHUR.

Sulphuric Acid, HYDROGEN SULPHATE, or OIL OF VITRIOL, H2SO4, is almost exclusively prepared by two methods the 'chamber' and the 'contact' pro

cesses.

a

The foundation of the former was laid by Ward about 1740, who prepared sulphuric acid by burning small charges of sulphur and saltpetre in the presence of water under a glass bell. The chemistry of the process is by no means clear, and there is much discussion as to the stages in which the reactions occur; but in effect it appears that sulphur dioxide in the presence of water is oxidized by nitrogen peroxide to sulphuric acid, NO2+SO2+ H2O=H2SO4+NO; the nitric oxide, to which the nitrogen peroxide has been reduced, is reoxidized to the peroxide by atmospheric oxygen, 2NO+O2=2NO2. Thus comparatively small quantity of nitrogen peroxide serves to oxidize an indefinitely large supply of sulphur dioxide. The details of the process vary somewhat with different makers, but are in general as follows: Sulphur or mineral sulphides in the form of pyrites are burned on the grate of a furnace, producing a gas that contains about 7 per cent. of sulphur dioxide, 10 per cent. of oxygen, and 83 per cent. of nitrogen, and leaving a residue of ferric oxide, 4FeS2+1102=2Fe2O3 + 8SO2. In the flues of the furnaces are placed earthenware pots, which can be charged with sodium nitrate and sulphuric acid, thus setting free nitric acid, NaNO3 + H2SO4

NaHSO4 + HNO3. About from 2 to 12 parts of sodium nitrate are used per 100 of sulphur burnt, according to the care with which the nitrous gases are preserved. The nitric acid is probably at once reduced by the hot sulphur dioxide to

nitric

oxide, 3SO2+2HNO3+2H2O= 3H2SO4 + 2NO, and the mixture of gases then passes up a Glover tower, in which the nitrogen oxides, which would otherwise be

lost at the exit of the apparatus, are restored. The gases then enter the large leaden chambers which are the characteristic feature of the process, and there, meeting water in the form of steam or very fine spray, the main reactions mentioned above take place. The chambers are usually in a series of three, one opening into the next. They are built of sheet-lead supported on a wooden frame, the sheets of lead being united without solder by melting the edges together. The bottom of the chamber forms a shallow tray, in which the weak acid formed by the reaction is collected, and whence it overflows into suitable receivers. In order to economize space, part of the chambers are, in some plants, re-. placed by plate towers, in which the gases are forced up cylinders filled with porcelain plates and meet water passing in the opposite direction. The gases then pass up a Gay-Lussac tower, down which concentrated sulphuric acid trickles over perforated plates or flints so as to scrub' the gases thoroughly and dissolve the nitrogen peroxide present; the residue, which is practically nitrogen, free from acid gases, escapes by the chimney. The nitrated acid from the Gay-Lussac tower is pumped to the top of the Glover tower mentioned above, where it is diluted by the addition of the weak chamber acid, and allowed to trickle down and meet the hot kiln gases. Under the influence of the dilution and the action of the sulphur dioxide the nitrogen peroxide contained in the acid is reduced to nitric oxide, and is returned to the gases to enter the chambers again. By this action, in which a considerable quantity of sulphuric acid is formed, and by the evaporative effect of the hot gases, the whole of the acid sent down the tower is concentrated.

Of the acid produced, much is utilized in manufactures in the form of the chamber acid directly obtained. This acid is about specific gravity 1.5 to 1.6 and contains from 60 to 70 per cent. of H2SO4. Part of it can be concentrated in the Glover tower to a specific gravity of about 1.72, corresponding to nearly 80 per cent. of H2SO4; a similar strength is obtained by evaporation in leaden pans. If required more concentrated, it must be evaporated in glass, or preferably platinum, stills. By these methods an acid of specific gravity 1.84, corresponding to 98 per cent. of H2SO4, is obtained; but, as a rule, the concentration is not carried further than from 93 to 95 per cent. Besides water and traces of oxides of nitrogen, oil of vitriol is liable to

contain lead sulphate and arsenic as its principal impurities. The former is precipitated by diluting the acid, while the latter can be removed by hydrogen sulphide, or its presence can be avoided by using sulphur dioxide from brimstone or from the hydrogen sulphide of the alkali waste recovery process. The con

centrated acid may also be purified by distillation. Anhydrous sulphuric acid may be obtained by freezing the concentrated acid and separating the crystals, but is better prepared by the contact process, by which fuming acid containing an excess of sulphur trioxide can also be obtained.

cess.

contact

In the contact process sulphur dioxide is prepared by burning pyrites as before, and is then very carefully purified, particularly from dust and arsenic, which are fatal to the success of the proThe gases containing sulphur dioxide along with excess of atmospheric oxygen are then heated to a carefully regulated temperature, and brought in with the catalytic agent, such as asbestos impreg nated with finely divided platinum or ferric oxide, usually the former, when the oxygen and sulphur dioxide unite to form sulphur trioxide, 2SO2+O2=2503. Heat is given out in the process, and is got rid of by making it warm the incoming gases, or dissociation of the product would take place. The sulphur trioxide formed is then absorbed in water, or better, dilute sulphuric acid, H2O+SO3=H2SO4, when acids containing any desired percentage of sulphur trioxide can be obtained. Fuming sulphuric acid is also called Nordhausen sulphuric acid, from its having been originally prepared at Nordhausen in Central Germany by heating partially oxidized ferrous sulphate, from which mixtures of sulphur dioxide, sulphur trioxide, and steam from the water of crystallization present are given off, the last two condensing as fuming sulphuric acid, while colcothar or ferric oxide is left, 2FeSO4 = Fe2O3+SO2 +SO3, and Fe2(SO4)2=Fez03+ 3SO3.

Pure sulphuric acid is a heavy colorless, oily liquid, which is without odor and does not fume. It is often of more or less brown color, from having taken up dust and organic matter. Sulphuric acid unites with water with great avidity, much heat being evolved in the process, so that the acid should always be diluted by adding it in a thin stream to water, and not conversely, or explosive ebullition may take place. affinity of sulphuric acid for water is so great that many substances are decomposed by it

The

with loss of water; thus, sugar is converted into a black carbonaceous mass and formic acid into carbon monoxide. It is owing to this property that the concentrated acid is used to dry gases, and that it has so great a corrosive power in destroying the skin, clothes, etc.; while the dilute acid, besides staining woollen fabrics red, rapidly rots textiles of any description. Sulphuric acid is intensely sour and is dibasic, forming both normal and acid salts, called sulphates, by interaction with metals, hydroxides, etc. With metals it behaves in two ways: if diluted and put with iron, zinc, etc., hydrogen is set free and a sulphate formed; while when concentrated and heated with copper, mercury, etc., a sulphate and sulphur dioxide is obtained. Concentrated sulphuric acid is without action on iron, and can safely be transported in iron tanks. When heated to boiling, sulphuric acid dissociates into sulphur trioxide and water. The sulphates, whether occurring naturally or derived from the acid, are a class of salts of great importance. Among the former, heavy spar, BaSO4, gypsum, CaSO42H2O, celestine, SrSO4, and Epsom salts, MgSO47H2O, are among the most important. The metallic sulphates are prepared artificially by the action of the metal, its oxide, hydroxide, or salt on sulphuric acid; the details in the individual cases depend on the solubility or otherwise, volatility, etc., of the products. As a class, the normal sulphates are characterized by being well crystallized stable salts, which, with the exception of those of lead and barium, are soluble in water; the insolubility of the latter is utilized as a test for sulphuric acid or any soluble sulphate a white precipitate being obtained when barium chloride is added to the solution. The acid sulphates or bisulphates, of which sodium hydrogen sulphate, NaHSO4, may be taken as typical, are in general similar to the normal sulphates, but have, in addition, a strongly acid reaction. The alums are an important class of double sulphates, in which, in general, an alkali-metal sulphate, such as of potassium, is crystallized with water and the sulphate, of either aluminium, chromium, ferric iron, etc., and forms a compound of the type K2SO4Al2(SO4)324H2O.

Sulphuric acid is used in the Leblanc process of making sodium carbonate, and in the bleaching, candle-making, galvanizing, tinplate, and aerated water industries. The production of sulphuric acid is an important chemical industry. Great Britain and the United States are the largest

producers, followed by France. The industry is also carried on in Austria, Italy, Belgium, Russia, and Japan. See Lunge's Sulphuric Acid and Alkali (new ed. 1903).

Sulphuric Anhydride. See SULPHUR and SULPHURIC ACID.

Sulphuric Ether is a misleading name sometimes given to ordinary or ethyl ether (C2H5)2O, for, though usually prepared by the aid of sulphuric acid, it contains no sulphur. See ETHER.

Sulphurous Acid, H2SO3, is unknown in the pure state, a solution of sulphur dioxide in water acting as this acid. This solution is colorless and smells strongly of sulphur dioxide, which is driven off again by heating or by passing air through it. It is acid to litmus and behaves as dibasic, giving rise to a series of both normal and acid salts-the sulphites-which are obtained by the action of the gas or its solution on hydroxides or carbonates of the metals. The normal salts, of which sodium sulphite, Na2 SO37H2O, is characteristic, are crystalline and without odor of sulphur dioxide, which is, however, readily set free from them by the action of acids. The acid salts, of which sodium bisulphite, NaHSO3, is typical, smell of sulphur dioxide-a feature which is also characteristic of salts, such as potassium meta-bisulphite, K2S2O, in which sulphur dioxide is united with the normal sulphite. The sulphites are employed, by reason of the sulphur dioxide they can evolve, as ducing agents and preservatives; sodium sulphite is largely used in this way in photography, and calcium bisulphite in brewing. The bisulphites are also valuable in the purification of acetone and aldehydes, as they form crystalline compounds with them.

re

Sulphur Springs, tn., co. seat of Hopkins co., Tex., 75 m. E.N.E. of Dallas, on the Mo., Kan. and Tex. and the St. L. S. W. R. Rs. It has two cotton-seed oil mills, brick plant, box factory, foundry, etc. It is situated in a fine agricultural district, and there are mines of lignite in the vicinity. Pop (1910) 5,151.

Sulphur Trioxide. See SULPHUR and SULPHURIC ACID.

Sulpicius, PUBLIUS Rufus (124-88 B.C.), Roman orator, began his career as a supporter of the Senatorial party. In 95 B.C. he accused the demagogic tribune Norbanus of treason; in 93 he was quæstor, in 89 he served under Pompeius Strabo in the Social War, and in 88 he was elected tribune. But before long he joined the party of Marius, who probably bought his support. He then brought forward and carried some democratic laws, and also passed a decree trans

ferring the command in the Mithridatic War from Sulla t Marius. He was slain in the Sullan proscriptions which followed.

Sultan, a Mohammedan title, signifying a ruling prince, as the sultan of Morocco. The title belongs especially to the Sultan of Turkey, or Sultan of sultans, or Padishah. The old English word is soldan.

Sultanpur, tn., cap. of Sultanpur dist., United Provinces, India, 58 m. N.N.E. of Allahabad. Pop. (1901) 150,000.

Sulte, BENJAMIN (1841), Canadian poet and historian, born at Three Rivers, Quebec. He was editor of Le Canada (Ottawa) in 1866-67, when he became translator to the Canadian House of Commons, whence he was transferred in 1870 to the Militia Department. He was one of the founders of the Royal Society of Canada, and its president in 1904. His works include: Les Chants Nouveaux (1880); La Poésie Française au Canada (1881); Histoire des Canadiens Français (1881); Pages d'Histoire du Can ada (1891).

Sulu, or JOLó. (1.) Isl., Philippines, in the middle of the Sulu Archipelago, of which it is the largest member. Area, 380 sq. m. It is traversed from N.E. to s.w. by three almost parallel mountain chains. There are twelve important summits, the highest of which is 2,894 ft. They are covered to the top with fine forests. Small streams are numerous, and considerable areas are under cultivation. Pop. (1903) civilized, 1.270; wild, 43,448. (2.) Pueb., Philippines, cap. of isl. and archipelago of Sulu, 595 m. from Manila, the ancient seat of the sultans of Sulu. The town has some pretensions to attractiveness. It has brick walls and redoubts, built by the Spaniards who cleared away the old town in 1878, and three fine streets shaded with banana, cotton, and fire trees. The houses are painted white. A stone pier extends 1,080 ft. into deep water, with a lighthouse at the extremity. It is the centre of the pearl industry and is in direct communication by steamer with Manila and Singapore. The population is estimated at several thousand.

Sulu Islands (JOLó, Span.), lying at the middle of the S. side of the Philippine Archipelago. Area, 1,029 sq. m. They extend from the w. peninsula of Mindanao, s.w. to the N.E. coast line of Borneo, 180 m., and separate the Celebes Sea on the S.E. from the Mindoro on the N. and the Sulu on the N.W. The larger islands are of volcanic origin, and are mountainous. The small ones are mainly coral and rise but little

Sulu Sea

above the surface of the ocean. The extreme verdure and semblance of cultivation make the Sulu Islands particularly charming. They fall into five groups, from N.E. to s.w., Balanguingui, Pangutárang, Sulu, Tapul, and Tawi Tawi. The staples are rice, coffee, chocolate, corn, hemp, saffron, indigo, sesame, and cotton. The Chinese intermediaries of commerce bring mechandise, opium, and tobacco, in exchange for pearl shell, sharks' fins, beche de mer, and native cordage. The shell fishery affords the most important occupation. The dominant race are the Moros, descended from the Mohammedan invaders. They were never completely subjugated by the Spanlards. Piracy was long one of their chief occupations, and their depredations were feared not only in the rest of the archipelago and Borneo, but from New Guinea to Singapore, and even in Polynesia. The Sulu language resembles more the Fijian than other Malay tongues. Pop. (1903) civilized, 1,270; wild, 50,119.

Sulu Sea, an inland body of water of the Philippine Archipelago. Panay and Negros lie on the N.E., Mindanao and the Sulu Is. on the S.E., Borneo on the S.W., and Palawan on the N.W. It is 300 nautical miles from N. to S., and 360 from E. to W.

Sulzer, JOHANN GEORG (172079), German-Swiss philosopher, was born at Winterthur. In 1747 he was appointed professor of mathematics at the Joachimsthal College at Berlin. Frederick II. appointed him professor of philosophy at the Military Academy (1763). His best known work is Allgemeine Theorie der Schönen Künste (1771-4), in which he sought for the moral origin of the fine arts. See his Selbstbiographie (1809).

Sulzer, WILLIAM (1863), American politician, born at Elizabeth, N. J. He received a common school education and was admitted to the bar in New York in 1884. He was a member of the N. Y. Assembly in 1890-94, becoming Democratic leader on the floor, and speaker in 1893. He was elected to Congress in 1894, and has served continuously since that date. He was a candidate for the Democratic nomination for governor in 1896 and 1906.

Sumach, a name applied to certain trees and shrubs belonging to the genus Rhus, a subdivision of the order Anacardiaceæ. The sumach or shumac of commerce is obtained from R. coriaria. It contains from 10 to 15 per cent. of tannin, and is employed in tanning light leather, and as a mordant in cotton dyeing. See RHUS and POISONOUS PLANTS.

537

Sumarokoff, ALEXANDER PETROVITCH (1718-77), Russian dramatist and founder of the modern Russian theatre, was born at Vilmannstrand in Finland. While a student at St. Petersburg he attracted attention with the tragedy of Horev. His collected works appeared in 1787.

Sumatra, isl., Dutch East Indies, lies N.W. to S.E. (5° 40' N. and 5° 59' s., and 95° 16' and 106° 3.45' E.), and has an area of 161,612 sq. m. The western side is very mountainous, and contains many volcanoes (6,000 to 10,000

Sumbawa

race; indeed, the Malays of the peninsula claim that their old ruling families came from Menangkabau in Sumatra. The Battas, or Battak, in the north, are less civilized than the other Malayan divisions, and still practise ceremonial cannibalism. The languages spoken are all variations of Malay, but the written characters are different. Sumatra, like Java, owed much of its early civilization to Indian immigration, which has left behind it some fine remains. Between the 13th and 16th centuries the people

ft.). The chief rivers (Musi, Jambi, Indragiri, Kampar, and Siak) all flow eastward, and the first two are navigable. The chief mineral products are coal and petroleum in Atchin, and gold. The temperature is tropical, but not unhealthy, and the island is covered with luxuriant forests. The chief products are pepper, rattan, gum, caoutchouc, nutmegs, spices, copra, coffee (in Palembang), and tobacco (in Deli). The chief town is Palembang (pop. 53,788). The population (1900) is 3,168,312, nearly 93,000 being Chinese. The other inhabitants are of Malay

became converts to Mohammedanism. The Portuguese in the 16th century acquired a few factories on the coast, which were later taken possession of by the Dutch, who have held them since, except during the British occupation of 1811-16. The British settlement of Benkulen existed intermittently from 1685 to 1825. Atchin in the N. has always been turbulent, and has only lately been subdued. See Marsden's Sumatra (1811), Breitenstein's Sumatra (1902), and Ireland's Far Eastern Tropics (1905).

Sumbawa, isl. of Little Sunda