Steam-engine

An engine worked by steam. The chief parts are the piston,cylinder, and valve gear. and The piston works in a cylinder, to which steam steel. is admitted by the action of the valve gear, caus¬ ing the piston to move backward and forward Sterkcil. and communicate motiou to the machinery. The with of common things 145 =turbine. A new form of steam motor, in which the steam is thrown against the valves of a turbine-wheel, which it causes to turn with great rapidity. These machines develop great power in small space. They have been placed in torpedo boats, driving them through the water at the unequaled speed of over 35 knots an hour. [Gk. stear, tallow.] A constituent of animal fats, as beef and mutton suet; and some vegetable fats as of cocoa. It is remarkable fol¬ ks solidity, and raises the melting-point of fat. It is prepared by mixing ether with suet, and is used in making soap. [AS.] A hard metal made by heating iron with charcoal. Steel is the form of iron in which the amount of carbon is intermediate between that contained in cast iron and in wrought iron. In steel, the carbon is either chemically united with the metal or di olved in it. It may contain silicon and manganese in small quantities, but sulphur or phosphorus is regarded as an impurity. It is malleable and ductile, fusible, and capable of acquiring, by being tempered, great hardne , which renders it suitable for cutlery and the different varieties of cutting tools. Steel was at one time always prepared from wrought iron by heating the bars for some time in contact with charcoal. This method of preparation is known as cementation. The proce of manufacturing steel known as the Be emer or pneumatic pro¬ ce is of very great industrial importance. It consists in blowing air through molten pig iron in a ve el called the converter. The carbon and the silicon which the pig iron contains are thus oxidized, and the iron is brought to the condition of wrought iron. After the iron is completely deprived of carbon, a certain quantity of pure cast iron is added in order to supply the carbon nece ary to convert it into steel. The metal is then cast into ingots. This kind of steel is used for railway axles and rails, for boiler plates, and for ships. Targe buildings, as churches, colleges, schools, are now made with frame-work of The walls are double, and the air between acts as a non-conductor of heat. A thin plate of metal or other material letters or a pattern cut through it. It is laid on a surface, a brush dipped in paint or ink over it, and the letters or pattern thus Stencils are much used by mer¬ to mark boxes or barrels. The vast, low plains of Europe and Asia, from Holland to Ru ia and thence Siberia and Mongolia. The name is applied to the broad and largely arid lands north and east of the Caspian, and Siberian lowlands. [Gk.] An optical instrument of with a slide for two slightly pictures of the same thing, which when through throws both pictures into one, gives the figures the appearance of solidity. [Gk.] A metal plate, being an copy in a solid form of a page of type. by plaster of Paris was discovered Gcd in the eighteenth century. Electrotypes 72 r