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olive oil. The compound thus procured cannot be regarded as a meresolution of sulphur in oil, since the odour of hydrosulphuric acid, whichit possesses, proves that the oil has undergone partial decomposition : infact, the heat to which the oil is raised in order to boil it, causes achemical change.
It is a dark reddish-brown viscid substance, having an extremely un-pleasant odour. Its local action is that of an acrid: its remote operationthat of a stimulant, causing thirst and febrile heat. It has been supposedto possess expectorant and diaphoretic properties. It is applied to foululcers, and is employed internally in chronic pulmonary affections. Thedose of it is from 40 to 50 drops: but its unpleasant taste and smellalmost preclude its use.
Ac'idum Sulphu'ricum.—Sulphuric Ac'id.
t
History, —This acid appears to have been known to Geber as early asthe seventh century (Thomson’s Syst. of Inorg. Chem. vol. ii. p. 29.) Inthe state in which we usually meet with it in English commerce, it istermed oil of vitriol, or the protohydrate of sulphuric acid.
Natural History . —It is found in both kingdoms of nature.
(a.) In the inorganized kingdom. —It is found in the w'aters of some vol-canic regions, and is evidently produced by the combustion of sulphur.
The Rio Vinagre (Vinegar River),which descends from the volcano ofPurace, in Colombia, to Popayan ,has received its name from its acidproperties, which it derives frombeing impregnated with sulphuric andhydrochloric acids (A. de Humboldt,Vues des Cordilllres, p. 220).
Issuing from the crater of MontIda, in Java, is a river which alsocontains this acid. Dr. ThomasThomson ( Mineralogy , vol. i. p. 75)states, that in Persia there is anearth so strongly impregnated with it,that it is used by the natives as anacidulous seasoner of food. Thisauthor also says {op. cit. p. 77), thatthere are no less than twenty-sevensulphates (consisting of combinations of sulphuric acid with one or morebases) in the mineral kingdom. The most abundant of these is the sul-phate of lime.
{b.) In the organized kingdom. —The sulphates of lime, potash, andsoda, have been found in plants (Decandolle, Phys. Veget. p. 390). Thesulphates of potash and soda are mentioned by Berzelius {Traite de Chim.t. 7 me , p. 393) as constituents of human urine.
Preparation. —The most improved method of manufacturing oil ofvitriol adopted in this country is the following:—Crude sulphur isburned on an iron plate in a furnace, and the gas (sulphurous acid),thereby produced, is conveyed by a pipe or chimney into a leaden cham-
Fig. 50.
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