Biscuits Vermifuges à la Santonine (Sulot.) Each biscuit contains 5 centigrammes of san tonin. (Reveil.)
Biscuits, dev′iled, in cookery, are captain’s biscuits (or any similar kind) buttered on both
sides, peppered well, and then covered on one side with a slice of good cheese formed into a paste with made mustard; the whole being seasoned with a little cayenne pepper is, lastly, grilled. Chopped anchovies, or essence of anchovies, is a good addition.
BISMUTH. Bi. Bismuth, Etain de glace, Fr.; Bismuth, Wismuth, W.-metall, Ger. One of the metals.
Bismuth furnace in section. a, Eliquation-tube.[182] b, End at which it is charged. c, End from which the metal flows. d, Receiving-pan. e, Water-trough. f, Grate, &c.[183] g, g, Draught-holes.
[182] Several of these tubes are usually set side by side together.
[183] Usually one to each eliquation-tube.
Sources. Bismuth occurs in the mineral kingdom in the metallic state (NA′TIVE BISMUTH), and in combination with sulphur (BIS′MŬTHĬNE), and with oxygen (B. O′CHRE, &c.). That of commerce is mostly imported from Saxony, where it is chiefly obtained from native bismuth by the simple process of eliquation. The ore, sorted by hand from the gangue, and broken into pieces of about the size of nuts, is introduced into the ignited iron pipes of the furnace (see engr.) until these latter are filled to about one half their diameter and to three fourths of their length. From these the liquefied metal is allowed to flow into iron pans containing some coal-dust, and from these into a trough of water, in which it is granulated and cooled. It is subsequently remelted and cast into moulds so as to form ‘bars’ varying in weight from 25 to 56 lbs. each. In this state it usually contains a small admixture of arsenic, iron, lead, and sulphur; from the first of which it may be freed by exposure for some time, under charcoal, at a dull red heat. It is best obtained in a pure condition by heating to redness, in a covered crucible, a mixture of oxide, or subnitrate of bismuth, with half its weight of charcoal.
Prop. Colour greyish-white with a reddish tint; crystalline; very brittle (may be powdered); melts at about 480° Fahr., and does not re-solidify until cooled to 6 or 7° below this point; it volatilises at a strong heat, and, in close vessels, the fumes condense unchanged in crystalline laminæ; little acted on by the air, but when exposed to it at a high temperature burns with a faint blue flame, emitting yellow fumes which condense into a yellow pulverulent oxide; when slowly cooled, in large masses, it forms large cubic crystals or octahedrons of great beauty; nitric acid, somewhat dilute, dissolves it freely. It is highly diamagnetic. Sp. gr. 9·8 to 9·83, which, by careful hammering, may be increased to 9·8827. A bar of bismuth, when heated from 32° to 212°, expands exactly 1⁄710 in length.