Wells's principles and applications of chemistry; . of prisms;but afterward, as the temperature is reduced, octohedronsare formed. The power possessed by sulphur of manifesting itself under two condi-tions, is, however, most strikingly illustrated by certain phenomena of itsmelting and subsequent cooling. Thus, if we heat a small quantity of sulphurin a glass flask over a spirit-lamp, it molts at a temperature of 250-280° F.,into a clear, yellow liquid. If a portion of this liquid bo poured into coldwater, it immediately condenses into the state it had before molting—that is,into common, yello
Wells's principles and applications of chemistry; . of prisms;but afterward, as the temperature is reduced, octohedronsare formed. The power possessed by sulphur of manifesting itself under two condi-tions, is, however, most strikingly illustrated by certain phenomena of itsmelting and subsequent cooling. Thus, if we heat a small quantity of sulphurin a glass flask over a spirit-lamp, it molts at a temperature of 250-280° F.,into a clear, yellow liquid. If a portion of this liquid bo poured into coldwater, it immediately condenses into the state it had before molting—that is,into common, yellow, brittle sulphur. If to the portion remaining in tlioflask a stronger heat bo applied (about 500° F,), the transparent fluid gra-dually thickens, becomes brown at first, and at last nearly black andopaque; in this condition the viscidity of the sulphur is such, that the flaskmay bo inverted without escape of its contents. If the heat be still further in-creased, the black, tenacious sulphur once moro liquefies, though it never be- FiG. Questions.—What is said of the allotropism of sulphur? What is tho first indicationof this property ? In -what two forms does sulphur crystallize f What are sxaniplcs JIn what other way may the allotropic properties of sulphur be illusti-ated ? 260 IN ORGANIC CHEMISTRY. comes as fluid as when first melted, at the temperature of 226° F., and ifsuddenly cooled, bj pouring it in a slender stream into cold water, it assumesa most singular state. It is no longer yellow and brittle, like ordinary sul-phur, or like the product of pouring into water the first result of fusion, butit remains soft, tenacious, highly elastic, and of a brown color, resembling, inall its external characteristics, strips of India rubber or gutta percha. In thisform it can be molded by the hand, and may be used to take impressions ofseals, medallions, etc. After the lapse of a little time, it again becomes yel-low, and returns to its original brittle condition, g
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectchemistry, bookyear18
