Blue is one of the seven colours into which the rays of light divide themselves when refracted through a glassprism, seen in nature in the clear expanse of the heavens; the term is also applied to a dye or pigment of this hue.
The substances used as blue pigments are of very different natures, and derived from various sources; they are all compound bodies, some being natural and others artificial. They are derived almost entirely from the vegetable and mineral kingdoms. The principal blues used in painting are ultramarine, which was originally prepared from lapis-lazuli or azure-stone - a mineral found in China and other oriental countries - but, as now prepared, it is an artificial compound of china-clay, carbonate of soda, sulphur, and charcoal; Prussian or Berlin blue, which is a compound of cyanogen and iron; blue bice, prepared from carbonate of copper; indigo blue, from the indigo plant. Besides these, there are numerous other blues used in art, as blue-verditer, smalt- and cobalt-blue, from cobalt, lacmus or litmus, etc.
Before the discovery of aniline or coal-tar colours dyers chiefly depended for their blues on woad, archil, indigo, and Prussian blue, but now a series of brilliant blues are obtained from coal-tar, possessing great tinctorial power and various degrees of durability.
Blue as a colour ranges from green-blue (turquoise) through to purple-blue (indigo).
Alice blue - A very light greenish-blue colour.
Aquamarine - A bluish-green colour.
Azure - A deep blue colour reminiscent of the sky.
Aquamarine - A pale greenish-blue colour.
Bice blue - A medium blue colour
Cambridge blue - A light blue colour.
Cobalt blue - A deep blue colour with a greenish-tint. The colour of old blue glass.
Enamel is a vitreous glaze of various colours fused to the surface of gold, silver, copper, and other substances. The art of enamelling, which is of great antiquity, was practised by the Assyrians and by the Egyptians, from whom it may have passed into Greece, and thence into Rome and its provinces, including Great Britain, where various Roman antiquities with enamelled ornamentation have been discovered. The enamelled gold cup given by King John to the corporation of Lynn, in Norfolk, proves that the art was known among the Normans. The Byzantines of the 10th century produced excellent cloisonne enamels on a gold base, the cloisonne process consisting in tracing the design in fillets of gold upon the gold plate and filling up the small moulds thus formed with enamels the design appearing in coloured enamels separated by thin gold partitions or cloisons. In some cases, however, the enamels were filled into hollows beaten out in the gold plate, which formed part of the field.
In the 12th century the town of Limoges acquired the high reputation for inlaid enamels which it held until the 14th century, aud re-acquired in the 16th for its painted enamels. The costliness of the sculptured ground had led the Italians early in the 14th century to substitute the practice of incising the design on the face of the plate, and then covering it with a transparent enamel. The further step, which made the Limousin workshops famous, consisted in the method of superficial enamelling, in which opaque colours or colours laid on a white opaque ground were used. The Limoges school degenerated greatly in the 17th century, but its method with certain modifications in detail is still employed.
The basis of all kinds of enamel is a perfectly transparent and fusibleglass, which is rendered either semitransparent or opaque by the admixture of metallic oxides. White enamels are composed by melting the oxide of tin with glass, and adding a small quantity of manganese or phosphate of calcium to increase the brilliancy of the colour. The addition of the oxide of lead, or antimony, or oxide of silver, produces a yellow enamel. Reds are formed by copper, and by an intermixture of the oxides of gold and iron. Greens, violets, and blues are formed from the oxides of copper, cobalt, and iron.
In the middle of the 18th century enamelling was largely applied to the decoration of snuff-boxes, tea-canisters, candlesticks, and other small articles. Of later years it was extensively applied to the coating of iron vessels for domestic purposes, the protection of the insides of baths, cisterns, and boilers, and the like. Enamelling in colours upon iron was common, iron plates being thus treated by means of various mixtures, and words and designs of various kinds being permanently fixed upon them by stencilling, for advertising, signboards, etc.
Green Paints are for the most part compounds of copper and of chromium. The best known greens are the following: Bremen green, or verditer, consisting mainly of a basic carbonate of copper. Brunswick green, a hydrated oxychloride of copper; but the name is sometimes given to a hydrated basic carbonate, also known as mountain green. Chrome and emerald green are oxide of chromium. Emerald green is also used as synonymous with Schweinfurt green. English green is a mixture of Scheele's green with gypsum. Guignets green is oxide of chromium prepared in a peculiar way. Hungary green is a kind of malachite found in Hungary. Rinman's green is obtained by heating zincoxide with a cobaltcompound. Saxony green is an indigo colour used in printing. Scheele's green is arsenite of copper, and Schweinfurt green, Veronese green, and Vienna green, are also compounds of arsenic and copper. Verdigris is a hydrated basic carbonate of copper, often seen in copper coins. Besides these are green colours derived from plants. Of these may be mentioned chlorophyll, the green colour of leaves: sap green, the juice of Rhamnus catharticus or buckthorn, made into a green lake with alumina; Chinese indigo-green, etc. Research Green Paint
Cobalt (so named from the Greek for goblin, a demon of the mines) is a greyish-white coloured metal element with the symbol Co. It was discovered among the ore veins in Cornwall in early times and called mundic by the miners. It was identified as a metal in 1733 by Brandt. Cobalt is very brittle, of a fine close grain, compact, but easily reducible to powder. It crystallizes in parallel bundles of needles. It is never found in a pure state, but usually as an oxide, or combined with arsenic or its acid, with sulphur, iron, etc.
Its ores are arranged under the following species: arsenical cobalt, of a white colour, passing to steel grey; its texture is granular, and when heated it exhales the odour of garlic; gray cobalt, a compound of cobalt, arsenic, iron, and sulphur, of a white colour, with a tinge of red; its structure is foliated, and its crystals have a cube for their primitive form; sulphide of cobalt, compact and massive in its structure; oxide of cobalt, brown or brownish black, generally friable and earthy; sulphate and arsenate of cobalt, both of a red colour, the former soluble in water. The great use of cobalt is to give a permanent blue colour to glass and enamels upon metals, porcelain, and earthenwares. Research Cobalt
The Cobalt RAQ was a series of low-cost servers based on the Linux operating system, first produced in 1996 by the Cobalt Microserver company. The servers proved very popular with Internet service Providers and smaller businesses and in 2000 Sun Microsystems purchased the company.
The Cobalt RaQ is a series of 1U rack mount server products that were developed by Cobalt Networks, Inc based upon a modified Red Hat Linux Operating System with a proprietary GUI for server management. Original RaQ systems were equipped with MIPS CPUs but later models used AMD K6-2 chips and then eventually Intel Pentium III CPUs for the final models. Th original RAQ1 was fitted with a 150 Mhz MIPS RM5230 CPU, the RAQ 2 with a 250 Mhz MIPS RM5231 CPU, the RAQ 3 with a 300 Mhz AMD K6 3DCPU, the RAQ4 with a 450 Mhz AMD K6-2 CPU, the RAQ XTR with an Intel Pentium IIICPU originally running at 733 or 933 Mhz and later 850 Mhz or 1 Ghz, and the final RAQ550 model was fitted with a 1 Ghz or 1.26 Ghz Intel Pentium III processor.In 2006 Sun decided to end production and support for the RAQ series of servers. Research Cobalt RAQ
Diamagnetic is a term applied to substances which, when under the influence of magnetism and freely suspended, take a position at right angles to the magnetic meridian, that is, point east and west. From the experimennts of Faraday it appears that all matter is subject to the magnetic force as universally as it is to the gravitating force, arranging itself into two great divisions, the paramagnetic and diamagnetic. Among the former are iron, nickel, cobalt, platinum, palladium, titanium, and a few other substances; and among the latter are bismuth, antimony, cadmium, copper, gold, lead, mercury, silver, tin, zinc, and most solid, liquid, and gaseous substances. When a paramagnetic substance is suspended freely between the poles of a powerful horse-shoemagnet it points in a line from one pole to the other, which Faraday terms the axial line. On the other hand, when a diamagnetic substance is suspended in the same manner it is repelled alike by both poles, and assumes an equatorial direction, or a direction at right angles to the axial line. Research Diamagnetic
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Ceruleum
