79G 



SULPHUR 



SULPHURIC ACID 



sulphites may be easily recognised by the facility 

 with which they dissolve the haloid salts of silver, 

 forming a solution of an extremely sweet taste, 

 and containing a double hyposulphite of silver and 

 soda, with an admixture nf chloride, imlide, or 

 bromide of sodium. It is this power of dissolving 

 those salts of silver which are insoluble in water 

 that renders the hyposulphite of soda useful in 

 photography. 



With hydrogen sulphur forms two compounds: 

 ( 1 ) Persulphule of Hydrogen, an oily liquid, having 

 the smell and taste of sulphuretted hydrogen ; (2) 

 Sulphuretted Hydrogen, H.S, known also as Hydro 

 sulphuric Acid and Sulphydric Acid, a natural 

 gaseous constituent of many Mineral Waters (<|.v.), 

 as for instance Harrogate and Strathpeffer in 

 (ireat Britain. It is formed spontaneously wher- 

 ever organic compounds containing sulphur undergo 

 putrefaction, as in stagnant sewers and cesspools 

 and in waters charged with organic matter and 

 sulphates. By acting on sulphide of iron with 

 dilute sulphunc acid, sulphate of iron is produced 

 and sulphuretted hydrogen liberated. 



FeS + H,SO 4 = FeS0 4 + H,S. 



Sulphuretted hydrogen is a poisonous colourless 

 gas, with the nauseous odour of rotten eggs. By 

 pressure it may be liquefied and solidified. It is 

 soluble in one-third of its volume of water ; but the 

 solution does not keep well unless preserved from 

 contact with air. It is readily combustible, burn- 

 ing with a blue flame, and forming water, sulphur- 

 ous acid, and usually a little sulphur. It has a 

 weak acid reaction, but combines readily with 

 bases forming sulphides. It is very poisonous, 

 birds perishing in air containing Ti V part, and 

 dogs in air containing ; ,',,-, pan of the gas. Owing 

 to its presence in illuminating gas silver becomes 

 tarnished in rooms where gas is burned, while 

 librarians lind the bindings of their books become 

 corroded by the sulphuric acid eventually produced 

 by the combustion of the gas. From its property of 

 forming insoluble sulphides with most metals, sul- 

 phuretted hydrogen is the sheet anchor of the ana- 

 lytical chemist. These insoluble sulphides again 

 are some of them produced in an acid solution, and 

 some only in an alkaline one. It follows that by 

 first acidifying the solution to lie analysed ami then 

 adding the sulphuretted hydrogen certain metals 

 will Ke removed as insoluble precipitates, while 

 others will have lieen unaffected. On now adding 

 an alkali a second portion will be removed, and so 

 a working method of separating the metals can lie 

 devised. The simplest test for sulphuretted hydro- 

 gen at the month of a drain is the use of blotting- 

 paper soaked in solution of acetate of lead. This 

 rapidly turns brown in presence of the gas. 



Sulphur combines with carlwn to form Bisulphide 

 of Carbon, CS,, a colourless, inflammable liquid, 

 heavier than water, and having a disagreeable odour 

 and taste. It is soluble in alcohol, but not in water, 

 and it is a powerful solvent of fats, sulphur, phos- 

 phorus, and india-rublier. Owing to its high refrac- 

 tive {tower it is used in the construction of prisms. 

 It may be obtained by heating fragments of char- 

 coal to bright redness in a porcelain tnlie, and 

 passing sulphur vapour along it. Its vapour wlien 

 freely inhaled exerts an ann-sthetic action similar 

 to that of chloroform and ether. Workmen in 

 caoutchouc or other manufactures in which bi- 

 sulphide of carbon is used as a solvent suffer from 

 prolonged exposure to itR vapour, which produces 

 headache, loss of appetite, impairment of vision 

 and hearing, and causes general derangement of 

 health by its deleterious action on the nervous 

 system. 



' Sulphur combines with chlorine in several pro- 

 portions, the most important of these compound* 



being the Dichloride of Sulphur, SCI., and thr 

 I'/ilnride of Sulphur, 8.CI,. Both of them are 

 liquids, and are formed by the direct action of 

 the combining element*. The chloride is a yellow 

 liquid which is decomposed by contact with 

 water sulphur, hydrochloric, and other acids 

 being produced. It is capable of dissolving about 

 67 per cent, of sulphur at an ordinary tcmpcnitmc, 

 and, like bisulphide of carbon, is extensively 

 employed in vulcanising india-mlilier. Thedichlor- 

 ide of sulphur is formed by saturating the chloride 

 with chlorine; a deep-retf liquid, resembling tin- 

 previous compound in most of it- properties; it 

 is decom|K>sed by the sun's rays into the chloride 

 and free chlorine. 



Sulphur seems to have been known from the 

 earliest times, and sulphuric acid was most prob- 

 ably known to the Arabians; the English manu- 

 facture of sulphuric acid dates, however, only from 

 the 18th century. Sulphur is used for various 

 purposes in medicine. It is given internally 

 either as sublimed sulphur (flowers of sulphur) 

 or as precipitated sulphur (milk of sulphur), 

 in somewhat large doses, as a mild cathartic 

 generally combined with jalap and cream of tartar. 

 The Confection of Sulphur of the Pharmacopoeia, 

 is composed of sulphur, cream of tartar, ami syrup 

 of orange-peel nibbed together the dose Ix-ing 

 from half an ounce to an qnnee, or from one to two 

 tablespoonfuls. In small doses sulphur is of great 

 value in coses of atonic gout and chronic rheuma- 

 tism. The external use of sulphur in the form of 

 ointment has been already noticed in the article 



ITCH. It is also used externally in other cntai u- 



disorders, particularly in lepra and psoriasis; it* 

 application in the form of vapour is often of 

 service. 



Sulphuric Acid, 1 1 S< ( .. is the chemical name 

 of the liquid commercially known as Oil of Vitriol 

 so called from its having been first produced by 

 the distillation of green vitriol (sulphate of iron). 

 It is an odourless, dense, oily-looking liquid, sp. 

 gr. 1*842. When pure it is colourless, but usually 

 it is of a straw to brown colour, derived from im- 

 purities which have fallen into it and been charred. 

 It has all the properties of a typical acid, Ix-ing 

 intensely corrosive and changing vegetable colours. 

 Exposed to the air it absorbs water, and when 

 mixed directly with water great heat is evolved, 

 the liquids contracting in bulk. It does not 

 evaporate at ordinary temperatures, and dilute 

 solutions spilt on cloth gradually become stronger 

 till the acid begins to destroy tin- fibres of the 

 cloth. Oil of vitriol, or the protohydrate, is not 

 the only hydrate of sulphuric acid. Three others 

 are known to exist. When the fuming oil of 

 vitriol of Nordhaiiscn is exposed to a low tem- 

 perature a white crystalline substance separate-. 

 which is a hydrate, containing half as much 

 water as the common liquid acid ; its formula 

 i- II,S() 4 S(),, and its fusing.point is 95 (35 ('A 

 Again, a mixture of 49 parts of the strong liquid 

 acid and 9 parts of water Iree/es at 47 (8'3" ' 

 and crystallises into splendid rhombic prisms, from 

 which property it is often termed glarnil sulphuric 

 in-,:!, with sp. gr. 1780. Lastly, when a very 

 dilute acid is concentrated by evaporation in twcuo, 

 at 212 (100 C.), till it ceases to lose weight, 

 there will be a resulting compound, consisting of 

 40 parts of the real acid and 27 of water, and 

 represented by the formula H s SO 4 2H a O. The com- 

 pound formerly known as anlii/ilnum sulphuric 

 acid possesses none of the characteristic properties 

 of an acid ; see SULPHURIC ANHYDRIDE. 



Sulphuric acid in its free state is a very rare 

 natural product ; although in combination with 

 liases it is common in the animal and vegetable, 

 and abundant in the inorganic kingdom. In plants 



