Cologne yellow is a pigment consisting of two parts yellow chromate of lead, one of sulphate of lead, and seven of sulphate of lime or gypsum. It is prepared by precipitating a mixture of nitrate of lead and nitrate of lime with sulphate of soda and chromate of potash. Research Cologne Yellow
Gilding is the art of applying gold-leaf or gold in a finely-divided state to surfaces of wood, stone, or metals. It is a very ancient art, being practised among the Egyptians, Greeks, Romans, and Ancient Persians. The processes employed through more modern times have been very varied. Metals are gilded either by what is called chemical gilding, mercurial gilding, by electro-gilding (electro-plating), or by the application of gold-leaf. Copper and brass, for instance, may be gilded by the process called wash or water gilding, with an amalgam of gold and mercury. The surface of the copper, freed from oxide, is covered with the amalgam, and afterwards exposed to heat until the mercury is driven off, leaving a thin coat of gold.
Gilding is also performed by dipping a linen rag in a saturated solution of gold, and burning it to tinder, the black powder thus obtained being rubbed on the metal to be gilded, with a cork dipped in salt water, until the gilding appears. Iron or steel is often gilded by applying gold-leaf, after the surface has been well cleaned, and heated until it has acquired the blue colour which at a certain temperature it assumes. Several leaves of gold are thus applied in succession, and the last is burnished down cold.
One process of chemical gilding was by dipping the article into a solution of gold, what is termed Elkington's solution being composed as follows: 5 oz. (troy) of fine gold; nitro-muriatic acid, 52 oz. (avoirdupois); dissolve by heat, and continue the heat until the cessation of red or yellow vapours; decant the clear liquid; add 4 gallons of distilled water, 20 lbs of pure bicarbonate of potassa and boiling for two hours.
Gilding on wood, plaster, leather, parchment, or paper, is performed by different processes of mechanical gilding. The first of these is oil-gilding, in which gold-leaf is cemented to the work by means of oil-size. In the case of paper or vellum the parts to be gilt receive a coat of gum-water or fine size, and the gold-leaf is applied before the parts are dry. They are afterwards burnished with agate. Lettering and other gilding on bound books are applied without size. The gold-leaf is laid on the leather and imprinted with hot brass types. Brass rollers with thin edges are employed in the same way for lines, and similar tools for other ornaments. When the edges of the leaves of books are to be gilt they are first cut smooth in the press, after which a solution of isinglass in spirits is laid on, and the gold-leaf is applied when the edges are in a proper state of dryness.
Japanner's gilding is another kind of mechanical gilding, which is performed in the same way as oil-gilding, except that instead of gold-leaf a gold dust or powder is employed. Frames of pictures and mirrors, mouldings, etc, are gilt by the application of gold-leaf, or by the cheaper process of 'German gilding,' that is, by tin-foil or silver-leaf, with a yellow varnish above.
Porcelain and other kinds of earthenware, as well as glass, may be gilt by fixing a layer of gold in a powdered state by the action of fire. The gold-dust or powder required in this operation may be obtained by precipitating it from a solution in aqua regia, either by means of iron sulphate or proto-nitrate of mercury. In order that the gold powder may be applied to the surface of the article to be gilt it must be well mixed with some viscous vehicle, such as strongly-gummed water. It is then laid on with a fine camel's-hair brush. Research Gilding
Securite is an explosive compound of ammonium nitrate and oxalate, with nitro- or di-nitro-benzene adapted for use in fiery mines as when exploded it is not liable to ignite fire-damp. Research Securite
A slow match is a simple type of fuse which smoulders very slowly. Traditional slow matches were prepared by soaking loose hemp cords in a dilute solution of potassium nitrate and then drying them. When ignited, such a fuse burns at a rate of about eight centimetres an hour. Formerly slow watches were employed in matchlock guns as a means of keeping a light ready for use over lengthy periods, and more recently in military and civil blasting to provide a delay action in various types of projectiles and in fireworks. Research Slow Match
Cellulose is the cellular tissue of plants. It is a member of the carbohydrate family and is allied to starch. In plants, cellulose is normally combined with woody, fatty, or gummy substances. With some exceptions among insects, true cellulose is not found in animal tissues. Microorganisms in the digestive tracts of herbivorous animals break down the cellulose into products that can then be absorbed.
Cellulose is insoluble in all ordinary solvents and may be readily separated from the other constituents of plants. Depending on its concentration, sulphuric acid acts on cellulose to produce glucose, soluble starch, or amyloid; the last is a form of starch used for the coating of parchment paper. When cellulose is treated with an alkali and then exposed to the fumes of carbon disulphide, the solution yields films and threads. Rayon and cellophane are cellulose regenerated from such solutions.
Cellulose acetates are spun into fine filaments for the manufacture of some fabrics and are also used for photographic safety film, as a substitute for glass, for the manufacture of safety glass, and as a moulding material. Cellulose ethers are used in paper sizings, adhesives, soaps, and synthetic resins. With mixtures of nitric and sulphuric acids, cellulose forms a series of flammable and explosive compounds known as cellulose nitrates, or nitrocelluloses. Pyroxylin, also called collodion cotton, is a nitrate used in various lacquers and plastics; another, collodion, is used in medicine, photography, and the manufacture of artificial leather and some lacquers. A third nitrate, guncotton, is a high explosive. Research Cellulose
William Henry Fox Talbot (Fox Talbot) was an English inventor. He was born in 1800 and died in 1877. Educated at Harrow and Trinity College, Cambridge he became renowned as a mathematician and spent most of his time studying scientific matters and archaeology. In 1833 he made the discovery - that of the action of light upon paper impregnated with silver iodide or silver nitrate - on which photography rests and published his findings in 1839, calling the process calotype, also known as talbotype. Research William Talbot
Amyl nitrate is a powerful poison with a specific action on the heart and blood-vessels. It is inhaled in small doses in certain diseases of the heart and in asthma. Nowadays, Amyl nitrite is used as a narcotic and sold under the name 'poppers'. It is popular amongst club goers, and particularly the gay community because of it's supposed property of enhancing sexual pleasure, where it contributes to the high instances of AIDs by its adverse effect upon the immune system. Research Amyl Nitrate
Congenital hypertropic pyloric stenosis is quite a common condition in new-born babies and its cause is not known. The thickened sphincter at the pylorus is very strong and spastic. The stomach enlarges and becomes powerful from working against obstruction. Persistent vomiting develops and owing to the force of the stomach this is described as 'projectile vomiting'. Waves of peristalsis may be seen in the child's abdomen and the hard lump of muscle at the pylorus can readily be felt. Occasionally x-ray examination is used to prove the diagnosis. In severe and neglected cases, gastritis develops. The child becomes extremely ill from dehydration, and constipation is a constant feature, the stools being hard from dehydration and starvation. Many cases are treated by Eumydrin (methylatropine nitrate) which is an antispasmodic drug given with the feeds. Surgical operation is however very often necessary and in skilled hands is practically without risk; recovery is more rapid and certain after operation, than with medical treatment. Research Congenital Hypertropic Pyloric Stenosis
A corn is a hardened portion of the cuticle of the foot, appearing as a sort of distinct growth, produced by pressure. Corns are generally found on the outside of the toes, but sometimes between them, on the sides of the foot, or even on the ball. They appear at first as small dark points in the hardened skin, and in this state stimulants or escha-rotics, as nitrate of silver (lunar caustic), are recommended. Perhaps the most efficacious remedy for corns is the application of glacial acetic acid night and morning.
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Matt and Leela Probert
Abbreviations
Research Cologne Yellow
