Zincum Pharm. Lond. & Edinb. Zinc, orTutenag: a bluish white metal; crackling, in being bent, like tin, and quickly breaking; about seven times specifically heavier than water; beginning to melt in a moderate red heat, and very slowly calcining on a continuance of the fire; in a moderate white heat flowing thin, burning, fulgurating, with a bright deep green or bluish green flame, and subliming into light white flowers, which concrete about the upper part of the vessel, or on the bodies adjacenc, into thin crusts, or soft loose filaments like down or cobwebs. In its metallic form, and in that of a calx or flowers, it dissolves readily in all acids, and precipitates from them almost all the other metallic bodies.

The calces Or flowers of zinc are difficultly revived into their metallic form. Though perfectly fixed in the fire so long as they continue in a state of calx; yet, as calces in general require for their revival a greater heat than that in which the metal itself melts, and as a full melting heat is the greatest that zinc can support; the instant they are revived, they burn and calcine again in open vessels, and escape through the pores of close ones. Hence some ores and preparations of this metal have been long kept in the shops, and even chemically examined, without being discovered to be such. The revival may be effected, by using compact vessels of such a structure, that the zinc, in proportion as it is restored to its metallic form by the charcoal powder or other inflammable additions commonly made use of for those purposes, may be suffered to sublime or run off from the heat without being exposed to the outward air; or by adding some other metallic substance to detain it, as copper, which is thus changed into brass,

This metal has but lately been received into the shops in its own form; in which it deserves a place, as affording preparations fupe-riour to the ores or productions of it now made use of. A white vitriol made from pure zinc, by dissolution in the diluted vitriolic acid and crystallization †, is doubtless preferable for medicinal use to the common impure white vitriol; and the white flowers, into which it is changed by deflagration ‡, to the very impure calamine and tutty. Moderately pure white flowers, sublimed from it in the brass or other furnaces, wherein zinc or its ores are melted with other metals, were formerly kept in the shops, and distinguished by the names of pompbolix and nihil album.

* The flowers of zinc were first used as an internal medicine by the celebrated chemist Glauber, but were little known in practice till Dr. Gaubius, of Leyden, gave an account of their virtues in his Adversaria. They have since been much employed in convulsive and spasmodic diseases, and sometimes with good effects. Even obstinate epilepsies have been rendered much less violent by their use. Like all other medicines, however, in diseases of this class, their good effects are often only temporary, and they often fail altogether. When the flowers are genuine, a grain or two generally at first excites nausea or sickness, but by degrees a considerable considerable dose may be taken with little or no sensible effect. As they are liable to be adulterated, it may be proper to mention, as tests of their purity, that they make no effervescence with acids; and that, when exposed to a strong heat, they become yellow, but on cooling, turn white again. An application for external use made by mixing one part of flowers of zinc with six of the simple liniment of wax and oil, is directed in the Edinburgh pharmacopoeia.

Vitriolum album Ph.Ed.

‡ Calx zinci vulgo flores zinci Ph. Ed.

Zincum cal-cinat. Ph. Land.