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Knight's Mechanical Encyclopedia (ed. Knight), B. (search)
nted towards the enemy. Ballistic pendulum. b. The other ballista was a cross-bow, arranged upon a standing frame (Fig. 546). The string was retracted by a tackle, and was cast loose by some device, projecting a dart or a stone, as the case might be. The dart or stone lay upon a table, and was adjusted against the string before casting off. Bal-lis′tic Pen′du-lum. This instrument is designed to determine the velocity of projectiles of cannon and small-arms. It was invented by Robbins about 1760, and described by him in his tract on Gunnery. It has been improved by Hutton and Gregory, in England; Piobert and Morin, in France; and Mordecai, in the United States. The original instrument consisted of an iron bar suspended by a transverse axis, and having a block of wood strengthened with iron plates to receive the impact of the ball. On being struck, the block swung like a pendulum, and pulled a ribbon through an orifice in the fixed framework. The length of the ribbo
Knight's Mechanical Encyclopedia (ed. Knight), K. (search)
ll timbers. The timbers, after saturation, should be placed under a shed or cover from the sun and rain, to dry gradually. In about 14 days timber not exceeding 3 inches in thickness will be perfectly dry and seasoned, and fit for use. Large timbers will require a proportionate time, according to their thickness. Some processes of similar import may be shortly stated. In Bethel's process, creosote is employed and forced under heavy pressure into the pores of the wood. (1838.) Robbins expels moisture by heat and then saturates with coal-tar, resin, or bituminous oils, at 325° Fah. (1865). Blythe treats with steam combined with hydrocarbon vapor. Burnett employs chloride of zinc in solution, under pressure. (1838.) Boucherie used pyrolignite of iron. (1840.) Payne, sulphate of iron. (1842.) Margary, acetate or sulphate of copper. (1837.) Van der Weyde, solution of silicate of potash. Heinemann: boil wood in alkaline solution, and treat, under pressure
Knight's Mechanical Encyclopedia (ed. Knight), P. (search)
pparatus for reducing straw to half-stuff for the manufacture of paper. The straw, after being cut up into short lengths, is immersed in an alkaline solution, and subjected to steam pressure in a boiler, after which it is washed and discharged from the boilers by the aid of a copious stream of water. The boilers are charged from above with stock and with water. The paper stock is stirred by chains on a rotating shaft, and is removed by lifting valve L. The fire is on a movable car E. Robbins and Southmayd's apparatus for treating bamboo and similar fibers consists of a retort A. boiler F, and digester D. Heat is applied to the retort and boiler, and vapor from oleaginous substances in the first, and steam from the second, are conveyed through the pipes C G to the digester D, in which the fiber is placed. The boiler and retort have direct communication through the pipe B, and each pipe is provided with a cock by which the proportions of steam and oily vapor admitted to the d
Knight's Mechanical Encyclopedia (ed. Knight), R. (search)
inch, and then secured by iron flanges held by bolts passing through them and the paper. The wheels then receive a steel or iron flagged tire. The advantages claimed for paper are, that it is noiseless, does not spring or shrink with the weather, affords a stay to the tire and a lateral support in turning curves, adapts itself to any trifling inequality of the inner surface of the surrounding tire, and is stronger than any other material of the same weight of which a wheel may be made. Robbins's car (Fig. 4128) is cylindrical and made of plate-iron. Hollow ribs F surround the interior of the body to stiffen it, and also to receive and discharge fresh air through different apertures; farther stiffening is likewise effected by semi-cylinders of sheet-iron and the wrought-iron floor. Attached to the roof-plate to support it are angle-irons, while an elastic platform serves to break the violence of collisions. Monitor car. It has been proposed to construct cars of a tapering
Knight's Mechanical Encyclopedia (ed. Knight), W. (search)
substances. （a.) The Seeley process; impregnation with creosote, carbolic acid derived from pine tar. （b.) Robbins's process: impregnation with heavy oils charged with creosote, carbolic acid, etc., derived from coal-tar at a higher teating it with compounds of petroleum, asphaltum, lime, zopissa, and sulphuric acid. Wood-preserving apparatus. L. S. Robbins's method consists in removing the surfacemoisture from the wood by heat, and then saturating it with the vapors of coatives. The following United States patents may be consulted:— No.Name and Year. 4,560.Von Schmidt, 1846. 47,132.Robbins, 1865. 48,636.Hamar, 1865. 49,146.Palmer, 1865. 49,382.Cooley et al., 1865. 52,046.Holmquist, 1866. 53,217.Eddy, 18e 412. Wool is also cleaned by treatment in a chamber with petroleum, or with sulphide of carbon; see Fig. 3378. Also Robbins's patent, No. 75,980, March 24, 1868. Wool-comb′ing. Said to have been invented by Bishop Blaize, who gave the na