SULPHUR.

397

Preparation. —Sulphur is procured in two ways; by the purification of nativesulphur, or by the decomposition of the native • sulphurets. The sulphur ofBritish commerce is almost exclusively obtained in the first way. It is broughtprincipally from Italy and Sicily. During the year 1830 no less than 236,338cwts. of rough brimstone were imported from Italy and the Italian islands. (Par-liam. Ref. 367, ordered to be printed, April, 1832.)

a. Purification of native sulphur. —In Sicily, from whence most of this sub-stance is procured, the native sulphur is submitted to a rüde process of fusion: itis collected in heaps, which are set fire to on the surface: the heat developed bythe combustion of one portion fuses another. (Daubeny, Deseriplion of Vol-canoes, p. 197.)

Another mode of purifying native sulphur is to distil it in earthen pots. Theseare arranged in two rows in a large oblong furnace, the top of each pot, which servesfor the introduction of the sulphur and for the removal of the residuum, beingkept closed during the Operation. The upper and lateral part of each pot com-municates with an inclined tube of about two inches diameter and fourteen long.When the fire is lighted in the furnace, the sulphur fuses and sublimes, andpasses through this tube into another pot, placed on the outside of the furnace,and perforated near its bottom to allow the melted sulphur to flow into a pailcontaining water, where it congeals, and forms the rough or crude sulphur (sul-phur cruthtm.) (Dumas, Tratte de Chimie, t. 1 er . p. 121.)

Crude sulphur is purified in this country. The process formerly adopted wasto submit it to fusion in an iron cauldron: the earthy impurities subsided, and theliquid sulphur was ladled out and cast in moulds. The improved method ofpurification is to submit it to distillation in an iron still.

For this purpose crude sulphur is put into an iron pot, set in brickwork, overa proper fire. To this is adapted an iron head removeable by a crane, and com-municating by two tubes or necks, the one with the sulphur Chamber, the otherwith the iron receiver, which is immersed in water. The communication be-tween the still and the receiver being shut off, the sulphur distils into the sulphurchamber, on the walls of which it is deposited in a pulverulent form. When ob-tained in this State it is called Flowers of Sulphur. The door into this chamberis placed near the ground, and is closed when the process is going on. If thecommunication between the still and the sulphur chamber be shut off by turningthe handle, and the communication between the still and the receiver opened, thesulphur distils over and condenses into a liquid which, when solidified, cousti-tutes the refined Sulphur of commerce. The elbow-pipe which forms the com-munication between the still and the receiver, is encased in a metal jacket, be-tween which and the tube a current of cold water is continually flowing from thebutt, and, after passing around the receiver, escapes, by a cock. The top of thereceiver is perforated by a vent pipe, and is supplied with a circular aperture (bywhich the liquid sulphur can be ladled out,) usually kept closed by a movea-ble lid.

The Stick, Roll, or Carte Sulphur (Sulphur in baculis; Sulphur in rotulis;Sulphur rottindum) is refined sulphur which has been cast in wooden moulds.

" Suhlimed Sulphur (Sulphur suh/imatum, L. T).,) commonly termed Flowersof Sulphur (Flores Sulphuris,) is apt to be contaminated with a little adheringacid (foimed by oxidation of sulphur,) which, in both the Edinburgh and Dublinpharmacopceias, is ordered to be removed by washing. [For this the U. S. Phar-macopoeia simply uses the word Sulphur, when unwashed, and Sulphur Lotumwhen washed.j

The Edinburgh College orders Sulphur sublimatum to be thus prepared:—,

"Sublime sulphur in a proper vessel; wash the powder thus obtained with boilingwater in successive portions tili the water ceases to have an acrid taste ; then dry the sul-phur with a gentle heat.

The Sulphur lotum of the Dublin PharmacopoGia is prepared by pouring bot water on