SUL

SUL

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It is decompofable by the fulphats of magne-fia, alumine, and zircon ; by the earthy nitratsand muriats; by the acidulous pholphat of lime;and the phofphats of alumine, glycine, andzircon; by the fluats of-barytes, ftrontian, andmagnefia ; the borats of potalh, foda, barytes,ftrontian and magnefia; and the carbonats ofpotafh, foda, and barytes. It is not made anyufe of.

Sulphite of Barytes.

This fait may be prepared, in the manneralready mentioned, with either pure barytes orthe carbonat reduced to a fine powder; or itmay be obtained by compound affinity froma mixture of an alkaline fulphite with muriat ofbarytes. It is in the form of a white powder,infoluble in water and taftelefs. By long ex-pofure to the air, it is converted into fulphat ofbarytes. When ftrongly heated, fulphur isdifengaged, and the refidue becomes fulphat.But this fait, though infoluble in water, maywithout much difficulty, be diffolved in liquidfulphurous acid, and by flow evaporation, maybe obtained in needle-form cryftals, or trun-cated tetrahedrons. Thefe cryllals are fome-times tranfparent, but often opake; they arehard and nearly infipid, but at length leave afulphurous flavour on the palate; they arerather lparingly foluble in water ; and the folu-tion is employed with advantage to purify thefulphites from any admixture of fulphat. Thecryfialiized fulphite confifts, according to Four-ty, 0 f

59. Barytes39. Sulphurous acid2. Water

100.

It is decompofed by the fulphats ; by the al-kaline phofphats ; by the nitrat and muriat offtrontian, and by the alkaline carbonats. It isnot made any other ufe of than that alreadymentioned.

Sulphite of Lime.

This fait is prepared either with pure or car-bonated lime, in the manner above defcribed.It is in the form of a white powder, but bydigeftion in liquid fulphurous acid, it difTolves,and by flow cooling cryftallizes in minutehexahedral prifms, with hexahedral fummits.To the tafte it is after fome time flightly ful-phurous. It is foluble in 800 parts of water*By expofure to heat the cryftals fall into pow-der, and a little water comes over; at a redheat, a little fulphur is difengaged, and the re-

595 )

fidue is fulphat of lime. By long expoiure tothe air, it becomes fomewhat efilorefcent, and,after a confiderable time, is changed into ful-phat. Its component parts, according to Dr.Thomfon, are

48. Sulphurous acid47. Lime5. Water

ICO.

It is decompofed by the alkaline and earthyphofphats; by the fluats and carbonats of ba-rytes, ftrontian, and the alkalies ; and by moltof the metallic falts. It is made no ufe of.

Sulphite of Magnesia.

This fait is prepared with carbonated mag-nefia diffufed in twice its weight of water, inthe manner already defcribed. It is in the formof powder, but by an additional portion offulphurous acid it readily diflolves, and bygradual evaporation it is depofited in the formof tranfparent deprefled tetrahedral pyramids.To the tafte it is at firft fweetifh and earthy,and afterwards fulphurous. When expofedto the air it becomes opake, and is very ilowlyconverted into a fulphat. It is foluble in 20parts of water at the common temperature;boiling water takes up an additional portion,which it depofits in cryftals on cooling. It isvery readily converted into fulphat by expofureto the air. When expofed to a dry heat itfoftens and afi’umes the confiftence of vifeidgum, and at length dries, having loft 45 percent, which is nearly pure water; at a higherheat the fulphurous acid rifes unaltered, andthe earth remains behind. From this mode ofanalyfis it appears, according to Fourcroy, t®confift of

39 Sulphurous acid16 Magnefia45 Water

100

It is decompofed by the alkaline and earthy-alkaline carbonats; by the fulphats of alumineand zircon; by the earthy nitrats; by thephofphats of the alkalies, and of lime, glycine,alumine, and zircon; and the alkaline borats.It is not applied to any ufe.

Ammoniaco-Magnf.sian Sulphite.

This fait is formed, according to Fourcroy,by mixing magnefia with fulphite of ammonia,or ammonia with fulphite of magnefia, or by3 n 3