Beta (13) iron, an unmagnetic, intensely hard and brittle allotropic form of iron, though normal and stable only in the little triangle GHM, is yet a state through which the metal seems always to pass when the austenite of region 4 changes into the ferrite and cementite of regions 6 and 8.
The essential characteristic of wrought iron was its nearly complete freedom from carbon; that of steel was its moderate carbon-content (say between 0.30 and 2.2%), which, though great enough to confer the property of being rendered intensely hard and brittle by sudden cooling, yet was not so great but that the metal was malleable when cooled slowly; while that of cast iron was that it contained so much carbon as to be very brittle whether cooled quickly or slowly.
For its extraction from zircon the mineral is heated and quenched in water to render it brittle, and then reduced to a fine powder, which is fused with three to four parts of acid potassium fluoride in a platinum crucible.
It forms a grey brittle mass, having a conchoidal fracture; it is very deliquescent, combining very energetically with water to form caustic potash.
Stantienite, a brittle, deep brownish-black resin, destitute of succinic acid.
The coalitions, once so brittle as to break at the first strain, had now been hammered into solidity by his blows.
The hair covering the body is long, coarse, and of a peculiarly brittle and pith-like character, breaking easily; it is generally of a greyish-brown colour, sometimes inclined to yellowish-red, and often variegated with lighter patches.
Similarly, bell-metal is harder, more sonorous and more brittle than either of its components.
The presence of minute quantities of cadmium, lead, bismuth, antimony, arsenic, tin, tellurium and zinc renders gold brittle, 2 ' 0 15th part of one of the three metals first named being sufficient to produce that quality.
Tellurium is a brittle silvery-white element of specific gravity 6.27.
From all the preceding the tiny dik-diks (Madoqua) of NorthEast Africa differ by their hairy noses, expanded in some species into short trunks; while the widely spread klipspringer, Oreotragus saltator, with its several local races, is unfailingly distinguishable by its rounded blunt hoofs and thick, brittle, golden-flecked hair.
At temperatures below o° C. it is pretty hard and brittle; at the ordinary temperature it is so soft that it can be kneaded between the fingers and cut with a blunt knife.
Rubber slowly absorbs oxygen when exposed to air and light, the absorption of oxygen being accompanied by a gradual change in the characteristic properties of rubber, and ultimately to the production of a hard, inelastic, brittle substance containing oxygen.
The same metal, when heated to 205° C., becomes so brittle that it can be powdered in a mortar.
It fuses at 415° C. and under ordinary atmospheric pressure boils at 1040° C. Its vapour density shows that it is monatomic. The molten metal on cooling deposits crystals belonging to the hexagonal system, and freezes into a compact crystalline solid, which may be brittle or ductile according to circumstances.
At about 200° C., the metal becomes so brittle that it can be pounded in a mortar.
Aluminium, iron, platinum and many other metals may thus take up so much carbon as to become brittle and unforgeable.
The class of furnaces heated by electrically incandescent materials has been divided by Borchers into two groups: (I) those in which the substance is heated by contact form at least so much carbide as would suffice, when diffused through the metal, to render it brittle, practically restricts the use of such processes to the production of aluminium alloys.
The faience is thick and clumsy, having soft, brittle and very light pale.
Gold and Zinc.-When present in small quantities zinc renders gold TABLE II.-Gold brittle, but it may be added to gold in larger quantities without destroying the ductility of the precious metal; Peligot proved that a triple alloy of gold, copper and zinc, which contains 5.8% of the lastnamed, is perfectly ductile.
Bismuth is a very brittle metal with a white crystalline fracture and a characteristic reddish-white colour.
A brittle potassium alloy of silver-white colour and lamellar fracture is obtained by calcining 20 parts of bismuth with 16 of cream of tartar at a strong red heat.
When present in other metals, even in very small quantity, bismuth renders them brittle and impairs their electrical conductivity.
Bright, glance or pitch coal is another brilliant variety, brittle, and breaking into regular fragments of a black colour and pitchy lustre.
It is of a pale brown colour, transparent, brittle, and in consequence of its agreeable odour is used for fumigation and in perfumery.
Ginseng of good quality generally occurs in hard, rather brittle, translucent pieces, about the size of the little finger, and varying in length from 2 to 4 in.
It is not brittle like porcelain and cast iron, not poisonous like lead-glazed earthenware and untinned copper, needs no enamel to chip off, does not rust and wear out like cheap tin-plate, and weighs but a fraction of other substances.
When shreds and nails are used, short thick wire nails and " medicated shreds " are the best; the ordinary cast iron wall nails being much too brittle and difficult to drive into the wall.
By the early Greek alchemists the metal was named Hermes, but at about the beginning of the 6th century, it was termed Zeusor Jupiter, and the symbol 2(assigned to it; it was also referred to as diabolus metallorum, on account of the brittle alloys which it formed.
The alloys of tin and gold are hard and brittle, and the combination of the metals is attended with contraction; thus the alloy SnAu has a density 14.243, instead of 14.828 indicated by calculation.
The crystals look like antimony, and are brittle, and so hard as to scratch glass and rubies; their specific gravity is 4.25.