A dispensatory, or commentary on the pharmacopoeias of Great Britain : comprising the natural history, description, chemistry, pharmacy, actions, uses, and doses of the articles of the materia medica / by Robert Christison.

  • Christison, Robert, Sir, 1797-1882.
Date:
1842
Catalogue details

Licence: Public Domain Mark

Credit: A dispensatory, or commentary on the pharmacopoeias of Great Britain : comprising the natural history, description, chemistry, pharmacy, actions, uses, and doses of the articles of the materia medica / by Robert Christison. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

    103/1042 (page 45)
    and fi'ee of water, it forms a tough crystalline solid, which melts at 66° into a mobile colourless liqvud, boils at a temperature towards 122°, and fumes when exposed to the air. It is composed of one equivalent of sulphur or 16.1 parts, and three equivalents of oxy- gen or 24 parts (SO'). In this state it is seldom seen, being pre- pai-ed merely for scientific purposes. The acid of commerce is ma- terially thfl'erent both in appearance and in properties. Two kinds ai-e more or less in use in the ai'ts. One, little known in tliis coun- tiy, and commonly called Fuming, Glacial, or Nordhausen sul- phm-ic acid, is an oily-looking liquid of a brownish colour, and a density about 1900, fuming when exposed to the air, and yielding when gently heated in close vessels the anhydrous acid already de- scribed. This sort is largely prepared at a long established manu- factory at Nordhausen, and is obtauied by heating the anhydrous sulphate of u'on to redness in a distilling apparatus. It sometimes contains a little sulphxuous acid, but consists essentially, and ac- cording to some of one equivalent each, of anhydrous acid and the other commercial variety of sulphm'ic acid, which is in the hydrat- ed condition. The latter kind is known on the continent by the name of English sulphuric acid, to distinguish it from the acid of Nordhausen. It is the only kind in use in Britain, and as such will alone form the subject of the following observations. Sulphui'ic acid is prepared in tliis country by subjecting sulphur and nitre together to strong heat along with a current of air, in consequence of which sulphurous acid and nitrous acid gas are dis- engaged. These are led into leaden chambers of great size, con- taining a thin stratum of water at the bottom. After a time the water becomes strongly charged with sulphuric acid, and being then withdrawn, the acid is concentrated by heating it strongly in glass retorts or platinum stills, so as to drive off most of the water. The nitrous acid in the fii'st stage of this process serves a peculiar and essential pvirpose. It converts the s;ilph\xrous into sulphuric acid, itself becoming hyponitrous acid by deoxydation ; the new acids immediately form with the watery vapoiu* in the chamber a crystalline compound of water, hyponitrous acid and sulphuric acid; this compoimd falling into the water is at once decomposed, and sulphuric acid remains, while hyponitrous acid and deutoxide of ni- trogen are disengaged, and at the same time combine in the air of the chamber with its oxygen to reproduce nitrous acid; and these chemical changes recur again and again, till the water is sufiicient- ly loaded with sulphuric acid. Commercial sulphuric acid thus prepared is a heavy, transpa- rent, colourless, oily-like fluid, without odour or fumes, but of an overwhelming and biu-ning acid taste. Its density varies between 1835 and 1840 or upwards; but when higher than 1845, this in- dicates the presence of more than the usual amount of impiu'ities. It freezes about 36° below zero, and boils a Httle above 600^* It is powerfully corrosive, speedily dissolving most animal or vegetable