INFLAMMABLES. 303 



(/.) In sulphuric acid, forming a constituent of the natural sul- 

 phates of lime, baryta, strontia, soda, &c. and in the free sulphuric 

 and sulphurous acids. 



3. PROPERTIES. 



(a.} Sp.gr. 1.99. 



(b.) Electric by friction ; color lemon yellow, but precipitated sul- 

 phur is at first white, and it becomes white if water be dropped on it 

 while in fusion, and also if sublimed with watery vapor ; the whiteness 

 is supposed to be owing to a combination with water ;* electricity, 

 negative or resinous ; a non-conductor of heat. Hence, a roll of it, 

 grasped in the hand, crackles in consequence of its brittleness, and 

 of its unequal expansion by heat. 



(c.) Emits a peculiar odor when rubbed or heated. Brittle and 

 fracture brilliant ; it has a considerable refractive power. 



(d.) Evaporates at 170, with a disagreeable smell ; fuses at 185 

 or 190 ; fluid at 220, most perfectly fluid between 230 and 280, 

 when it is of an amber color. 



(e.) It begins to thicken at 320 ; at 350, stiffens and acquires 

 a deeper color ; f is very tenacious between 428 and 482, but 

 from that to its boiling point, it grows fluid again, and on cooling, also, 

 it recovers its fluidity ; this may be repeated by sudden transitions of 

 temperature in close glass vessels ; otherwise the sulphur is volati- 

 lized. J 



Evaporates at 290 ; it can be distilled from a glass retort into a re- 

 ceiver. 



(/.) Sublimes at 600. The sulphur being thrown on an ignited 

 iron, and covered suddenly with a bell glass, the latter is instantly lined 

 with the sublimate called flowers of sulphur ; melted, skimmed, de- 

 canted, and cast in moulds, this forms the best roll sulphur .$ 



* It is said also to acquire a paler color from adulteration with rosin, flour, &c. 



i In this state, or when heated to 428, it is poured into hot water, and is used to 

 copy medals, they being impressed upon it while it is warm. 



I Thenard, I, 107, quoted by Henry, Vol. I, p. 380. 



Rough sulphur is purified by melting it in cast iron bodies or retorts, covered 

 with earthen ware heads ; about six cwt. at once, and the distilled sulphur is 

 drawn off into water, at the lower of three holes in the receiver; one being for 

 the admission of the retort, and one for the escape of the vapors ; the refined sulphur 

 is cast in moulds made of beech wood. In subliming sulphur, the furnace is below, 

 and the sulphur, melted in iron pots, rises into a room placed above, where it is con- 

 densed in flowers or sublimate. 



It is sublimed also from thick iron pots, of the capacity of 10 or 12 cwt. by a lateral 

 communication from its dome into a chamber, which, if intended for roll sulphur, rnay 

 be not more than one fifth the size that would be requisite, if flowers of sulphur were 

 to be made. Gray's Op. CJiem. 



If the distillation is rapid and incessant, it will condense in the liquid form, and 

 will be made into roll sulphur ; if slow and with suspension at night, it will be in the 

 form of flowers. Formerly, crude sulphur was merely melted, and when the impuri- 

 ties had subsided, it was ladled out and cast in moulds; the sulphur thus obtained 

 was impure, and much was lost in the sediment; the best roll sulphur, as well as 

 flower:?, has been distilled or sublimed. 



