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Prometheans were the first safety matches. They were invented in 1805 by a French chemist named Chancel, and consisted of splints of cedar wood ripped with a past of chlorate of potash mixed with sugar. On dipping the match into a bottle containing asbestos wetted with sulphuric acid it burst into flame upon drawing it out. Prometheans were introduced into Britain following the Battle of Waterloo.
 Research Prometheans
Asbestosis is a chronic disease of the lungs allegedly caused by the inhalation of asbestos fibres, sometimes leading to lung cancer. Asbestosis is one of the pneumoconiosis group of occupational diseases.
Research Asbestosis
Mesothelioma is a tumour of the mesothelium. The term is particularly used to describe a tumour of the mesthelium apparently caused by exposure to asbestos (asbestosis).
Research Mesothelioma
In medicine, the mesothelium is the epithelium that forms the surface layer of the mesoderm and lines the embryonic body cavity. Tumours of the mesthelium are allegedly caused by breathing asbestos fibres, this forming the condition known as mesothelioma.
Research Mesothelium
A gasket is a compressible packing piece of paper, rubber, asbestos, or other material, sandwiched between the faces of a metal joint to provide a seal.
Research Gasket
The first lucifer matches, originated by Chancel in 1805, consisted of sticks tipped with a mixture of potassium chlorate and sugar, bound together by gum, and were fired by touching the tip upon concentrated sulphuric acid, which was carried separately in a bottle and soaked up in asbestos. These matches began to displace the tinder-box from about 1820, and they were the chief matches in vogue until the middle of the 19th century when their place was taken by friction matches.
Research Matches
Portland cement is the essential constituent in concrete, cement rendering and formerly in asbestos-cement sheeting. Portland cement is produced by burning limestone with clay or shale at a high temperature until it forms a clinkered mass, which is then cooled and ground into a fine powder.
Research Portland Cement
If a steel poker is pushed into the fire and left there for a time the handle becomes warm. Heat travels through the metal by a process called conduction. This process is complex. It differs between metals and non-metals. When a metal is heated the free electrons which it contains begin to move faster, i.e., their kinetic energy increases. The hot electrons then drift towards the cooler parts of the metal and at the same time there is a drift of slower-moving (cooler) electrons in the reverse direction. In those substances where no free electrons are present the process of conduction is entirely different. In such cases the heat energy is conveyed by longitudinal waves, similar to sound waves, but of considerably higher frequency. These waves are transmitted in tiny energy packets called 'phonons'. Most metals are good conductors of heat; silver and copper are exceptionally good. On the other hand, substances such as cork, wood, cotton and wool are bad conductors. Both good and bad conductors have their uses.
The best kettles, other than electric kettles, are made of copper, since heat is conducted most rapidly through this metal. The 'bit' of a soldering iron is also made of copper, so that when its tip is cooled through contact with the work, heat is rapidly conducted from the body of the bit to restore the temperature of the tip and maintain it above the melting point of solder. Bad conductors have a very wide application. Beginning with our personal comfort, we prevent loss of heat from ourselves by a covering of poorly conducting material. Textiles are bad conductors of heat, since they are full of tiny pockets of air enclosed by the fibres of the material. Air, in common with all gases, is a very bad conductor of heat. It is usual to say that wool is warmer than cotton. Technically, of course, we imply that it has a lower thermal conductivity than cotton. A stone floor feels cold to the bare feet, but a carpet on the same floor feels warm. This difference arises from the fact that stone is a better conductor of heat than a carpet. To begin with both the stone floor and the
carpet are at the same temperature. Since the feet are warmer than either, heat tends to flow from the feet. Stone, being the better conductor, conveys heat away from the feet more rapidly than the carpet. Consequently, the feet feel cold on the stone but warm on the carpet. Precisely the same effect is experienced when handling a garden fork in winter. The iron part of the fork feels cold, but the wooden handle warm.
Loss of heat by conduction through the walls of an oven is reduced by constructing it with double walls. The space between is packed with slag wool or glass fibre. These substances are not only very poor conductors but also have the merit of being non-inflammable. Material of low thermal conductivity used for the purpose of preventing heat loss is called lagging. Another example is the covering of hot-water storage tanks and pipes with a layer of plaster mixed with asbestos or other insulating material. Similarly, cold-water pipes may be lagged with strips of felt or sacking to prevent freezing during very cold weather.
Research Transmission of Heat
Actinolite is a mineral that commonly occurs in crystalline schists, often being the chief constituent of green-coloured schists and greenstones. It is used somewhat as an asbestos material. It has the formulae Ca2(Mg,Fe)5Si8O22(OH)2 (the same as nephrite, but being less attractive and harder to cut and polish is less valuable than nephrite) and a relative hardness of 6.
Research Actinolite
Amianthus is a soft, silky variety of asbestos.
Research Amianthus
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The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
©1993 - 2009 The Probert Encyclopaedia
Southampton, United Kingdom
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