SULPHURIC ACID 



SIMACII 



filled with a quantity of cither nitrate of soda or 

 nitrate of potash, with sulphuric acid sufficient fur 

 it* decomposition 8 or 10 Hi. of tin- nine with 5 

 or 6 Ib. of sulphuric acid lieing allowed for every 

 cwt. of sulphur. The decomposition of the nitre 

 by the action of heated sulphuric acid furnishes 

 nitric acid fumes, which go over into the chamber 

 along with the sulphurous acid. The sulphurous 

 acid readily abstract* from the nitric acid the 

 additional oxygen required for its conversion into 

 sulphuric acid, reducing the nitric acid to nitric 

 oxide, NO. Nitric oxide in it> turn quickly con- 

 verts itself into nitric peroxide, by the abstraction 

 of additional oxygen from the air that is constantly 

 entering the chamber through the burners. Again, 

 in the presence of moisture which is supplied by a 

 jet of steam from the boiler, C, sulphurous acid 

 readily deprives the nitric peroxide of oxygen, and 

 thus forms more sulphuric acid, and again liberates 

 nitric oxide ; which is ready once more to seize 

 upon the oxygen of the air, and would continue so 

 acting and reacting ml in fin it n in, were it not 

 carried forward and out by the chimney. 



The chamber is an immense box or room of lead, 

 bound together with a strong framework of timber, 

 and generally raised on arches several feet above 

 the ground. Chambers vary in size from 60 to 140 

 feet in length, and from 20 to 40 feet in width and 

 height. Curtains of lead proceeding alternately 

 from the bottom to near the top, and vice versa, are 

 very frequently used ; they serve to retard the 

 progress of the gases, and thus ensure the trans- 

 formations desired. The floor of the chamber is 

 covered with water, into which the sulphuric ucid 

 falls as it is formed ; and when this solution attains 

 a certain strength it is tapped off for concentra- 

 tion. When the gases reach the chimney, on 

 account of the reactions of the nitrous compounds 

 already explained, a large amount of nitrous acid 

 would not only lie wasted, but would also be dele- 

 terious to the neighbourhood, were steps for ite 

 recovery not adopted. This recovery is usually 

 effected by menus of a tower filled with coke, h, 

 down which a constant stream of strong sulphuric 

 acid trickles, the acid absorbing the nitrous fumes 

 in their way upwards. Instead of a single chamber, 

 curtained off or not as the case may be, sometimes 

 three or live distinct chambers, connected by pipes, 

 are employed, those communicating directly with 

 the burners being termed working chambers, and 

 the others receiving chambers, the last either 

 acting as or communicating with a condenser or 

 chimney. 



When iron pyrites is used as the source of 

 sulphurous acid suitable burners are used. In 

 Kngland these are arched chambers about four 

 feet each way, on plan with furnace bars placed a 

 little above the ground. There are also the 

 necessary doors and air-holes. The pyrites is 

 broken into pieces and spread in layers' on the 

 bars, which arc previously heated to redness, and 

 the heat evolved by the burning sulphur is there- 

 after sufficient for the fresh charges. The exhausted 

 ore is frequently sufficiently rich in copper for ite 

 extraction; indeed, when there is as little as 2J 

 per cent, present in pyrites it is now recovered. 

 In consequence of st roii^r sulphuric acid alworhing 

 both sulphurous acid and nitrous acid, the acid 

 requires to be drained off from the chamber while 

 the solution is comparatively weak, at which 

 strength viz. of a specific gravity of about 1 '4 it 

 is used for -ome purpose- in the arts under the 

 name of ' Chamber Acid. ' This is concentrated* by 

 evaporating in lead pans, I), till it reaches the 

 specific gravity of I'fi, then boiling in a platinum 

 retort, on which strong acid does not act, even at 

 high heat, or in large flint-glass retort*. In the pro- 

 introduced in 1RT>9 by Mr Glover the gaseous 



sulphuric acid from the sulphur or pyrites burners 

 i- not conducted direct to the lead chanil>cr, but 

 is lirst passed through a (Mover's or denitraling 

 tower, and there purified of nitrogen compounds, 

 which are saved for use in the lead chaniU-r. 



I lie manufacture of sulphuric acid is a very 

 c\ien-i\c industry : immense ijuantities of it lieing 

 consumed in the manufacture of Soda (q.v.), in 

 that of bleaching ]x>\\ dcr, in calico printing and 

 dyeing, and in fact in most chemical oj-ra- 

 tion- both in the manufactory and the laboratory. 

 In medicine a dilute sulphuric acid, formed by 

 gradually mixing the strong purified acid with 

 water, or aromatic sulphuric acid i [known also as 

 elixir of vitriol), prepared by mixing sulphuric 

 acid, rectified spirit, tincture of ginger, and spirit 

 of cinnamon, are almost alwa\s employed. In 

 doses of from ten to thirty minims, properly di- 

 luted, these preparations exert a strong asti iiigcnt 

 power, and are serviceable in all forms of passive 

 Im-morrhages, and in checking inordinate ills- 

 charges when thev arise from debility. 1'oi-oning 

 with this and other irritant acids is noticed at 

 POISON, Vol. VIII. p. 265. 



There are works on the manufacture by Smith ( 1873 ), 

 Lock ( 187H), and Lunge (new ed. 1W1 ). 



Sulphuric Anhydride, SO,, is obtained by 

 distilling fuming Nordhatisen sulphuric acid, a 

 fibrous mass of silky crystals lieing deposited in 

 the receiver. It may also be prepared by the 

 distillation of anhydrous bisulphate of soda. It is 

 a tough solid, melting at 65 (1H-3"C.), and pos- 

 sessing none of the properties of an acid, not even 

 affecting the skin. In contact with moisture much 

 heat is developed, and it then possesses the corro- 

 sive properties of sulphuric acid. 



Sulphuric Ether. See ETHER. 

 Sulphurous Acid. See SULPHUR, p. 795. 



Sulpiciaiis. an order of priests for training 

 young men for the church, founded in 1645, and 

 named from the church of St Sulpice (q.v.) in Paris. 



Snlpicius Severus (363-410), a Christian 

 historian, bom in Aquitaine, who wrote a Historia 

 Sacra from the Creation downwards, and a Life of 

 St Martin ( q. v. ) of Tours. 



Snl I. -i n (Arab., Turkish, and Persian Suit mi), 

 a Mohammedan ruling prince or monarch, as of 

 Morocco or Zanzibar ; especially used of the 

 Sultan of Turkey, who calls himself Sultan of 

 Sultans. The name of Sultana is given to the 

 mother, wife, or daughter of a sultan. The old 

 English form of the word was Soldan or Sowdan. 



Sllln Islands, an archipelago stretching from 

 Borneo north-eastwards to the Philippines, in the 

 south-east of Asia. The group, numbering 162 

 islands in all, most of them mountainous and all 

 covered with luxuriant vegetation, has a total 

 area of 94S s,|. m. and a total ]Kip. of 75,000. The 

 inhabitants. Malays by race and Mohammedans 

 1>\ leliginn, were bold pirates, until the Spaniards 

 conquered them in |S7li. The latter retired from 



the archipelago a- a result of the Spanish -A rican 



war ( 1898), ami in IS'W the sultan of Snlu acknowl- 

 edged the sovereignty of the I'nited States. The 

 town of Snlu was taken in 1S.~>1 by the Spaniards, 

 by whom it was much improved. Itisontne north- 

 west coast of Sulu Island, and hasagood roadstead. 



Miin.-i.li. Sumac, or SHUMACK (/.'/</,*), a 

 genus of small trees and shrubs of the natural 

 order Anacardinec:c ; having small inconspicuous, 

 (lowers in panicles or in corymlis, and the fruit a 

 small, nearly dry drupe. The' species are numerous, 

 dill'uswl over almost all parts of the world, except 

 ite coldest regions and Australia; some of them 

 are useful in the arts and in medicine, and some 



