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Knight's Mechanical Encyclopedia (ed. Knight) 23 1 Browse Search
Thomas Wentworth Higginson, John Greenleaf Whittier 4 0 Browse Search
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Browsing named entities in Knight's Mechanical Encyclopedia (ed. Knight). You can also browse the collection for F. A. P. Barnard or search for F. A. P. Barnard in all documents.

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Knight's Mechanical Encyclopedia (ed. Knight), A. (search)
re deduced the three conclusions following, namely, — I. The resistance is directly as the length of the tube. II. It is directly as the square of the velocity of flow. III. It is inversely as the diameter of the tube. See Report of Dr. Barnard, United States Commissioner at the Paris Exposition. This great work is happily completed. See tunnel. In the Verpilleux pump, water is made the means of transmitting power. See force-pump. The transmission of power by means of cospheres of pressure to reduce it to liquefaction. The same effect is produced at the freezing-point of water by a pressure of five atmospheres, at 21° C. (70° Fahr.) by a pressure of nine, and at 38° C. (100° Fahr.) by a pressure of fourteen. — Barnard. Lamm's Ammonia Engine is driven by the expanding pressure of liquefied ammonia, and is specially adapted for small powers, especially portable engines for street cars, etc. The ammonia is to be liquefied at a central station, at which the r
Knight's Mechanical Encyclopedia (ed. Knight), C. (search)
a pressure of from 50 to 60 pounds to the square inch, and the air is conveyed by metallic tubes to the bottom of the mine, and by a caoutchouc tube to the engine. It undercuts 3 feet deep and 150 feet long in 8 hours. One of the Mount Cenis Tunnel air-compressors, invented and constructed by Sommeilleur, and placed at Bardonneche, the Italian end of the tunnel, is represented by a vertical longitudinal section on the page opposite. The description is condensed from the report of Dr. F. A. P. Barnard, United States Commissioner to the Paris Exposition. The compressors operate by applying the living force of a large column of water descending in an inclined tube A, to drive a body of confined air into a receiver B, within which there is maintained a constant pressure of six atmospheres by means of an hydraulic head. Each compressing-engine is an inverted siphon, having the long arm A inclined and the short arm C vertical. The puppet-valve D is for the purpose of regulating the
Knight's Mechanical Encyclopedia (ed. Knight), G. (search)
eavy piston, whose rod is a rack acting upon a cog-wheel on the fly-wheel shaft; as the piston ascends, the cog-wheel slips loosely on the shaft. The mixed gases, coal-gas and air, are exploded by communication with the gas-jet, which is kept constantly burning. As the gases rapidly condense after the explosion, the atmospheric pressure, aided by the weight of the piston, is made effective upon the shaft of the wheel by the engagement of the rack-teeth with those of the spur-wheel. See Dr. Barnard's Report of the French Exposition, pp. 60 – 63. The same excellent report gives an account and illustration of the Lenoir gas-engine, of which three hundred were, in 1862, in use in France. The essential portions are a horizontal cylinder with a piston which communicates motion by a crank to a shaft which carries a heavy fly-wheel. The great weight of this wheel is for a double purpose: to absorb the force suddenly developed by the explosion, and so moderate the speed at this period; a
Knight's Mechanical Encyclopedia (ed. Knight), H. (search)
hospital train for a division, and will accommodate 200 patients, requiring 13 surgeons and 74 men for their care. Hot-air Engine. One driven by the heating of a body of air admitted to the cylinder. They are of two kinds:— First, those which draw their supplies directly from the atmosphere, and discharge them into the atmosphere again after they have produced their effect. Such are the Ericsson, Stillman, Roper, Baldwin, Messer, Wilcox engines, described on pp. 40-43. See also Dr. Barnard's report on the French Exposition, pp. 34-40, and plate 1. Second, those which employ continually the same air, which is alternately heated and cooled, but which is not allowed to escape. Such are the Glazebrook (1797), Parkinson and Crosley (1827), Laubereau (1849), Schwartz, described on pp. 43, 44. These and other distinguishing features are described under air-engine(which see). Hot-air Fur′nace. One in which air is heated for warming houses, or for purposes of drying, us
Knight's Mechanical Encyclopedia (ed. Knight), I. (search)
pelled by slightly warming the compound. If the chloride be heated to 100° Fah., the ammonia expelled, and the other end of the tube plunged in a cold bath, the gas becomes liquefied. If now the end containing the compound be plunged in a refrigeratory and the other in water, the liquid ammonia will commence boiling, the chloride will reabsorb the vapor as fast as produced, and by the rapid evaporation the water around the tube will be converted into ice. For economic reasons (see Professor Barnard's Report on the French Exposition, page 369) water is to be preferred to chloride of silver. Water absorbs at moderate temperature 700 times its own volume of ammoniacal gas, a volume capable of producing a quantity of liquid ammonia equal to two thirds the bulk and one half the weight of its own volume, and capable of converting into ice more than three times its own bulk. On the contrary, a given quantity of chloride of silver will produce only a thirtieth part of its bulk of liqui
Knight's Mechanical Encyclopedia (ed. Knight), M. (search)
e engine is automatic as to both. It is also distinct from a tool, as it contains within itself its own guide for operation. Ma-chine′--tool. A machine in which the tool is directed by guides and automatic appliances. Aptly called by Dr. Barnard a mechanical artisan with iron arms. It is a workshop appliance for operating upon materials in the way of shaping and dressing, having devices for dogging the stuff and feeding the tool. Among tools of this class for working in metal may locked up by bringing down a traverse bar at the top, so as to compress the whole mass and secure it in place. The matches are thus confined as in a printer's chase. They are then evened at their end like type, and are ready for dipping. — Dr. Barnard's Report Paris Exposition. Match-making machine (section). Match-gear′ing. （Gearing.) Two cog-wheels of equal diameter geared together. Match-hook. A double hook or pair of hooks in which one portion forms a mousing for the o
Knight's Mechanical Encyclopedia (ed. Knight), N. (search)
had believed that they had resolved these bands, but as they had not succeeded in ascertaining the number of lines in each individual band their claims were not universaily accepted. On the receipt of the Museum photographs, Nobert for the first time acknowledged that the highest four bands had been resolved, and promised that he would endeavor to rule still finer lines. The new twenty-band plate was the result of his subsequent efforts. One of these plates was furnished by him to President Barnard of Columbia College in 1872, and in the spring of 1873 another was received at the Army Medical Museum. Systematic endeavors with the best modern objectives have failed as yet to resolve any of the bands of this plate beyond the tenth, and hence perhaps some will be disposed to deny that they have actually been ruled as stated, but it must be remembered that similar doubts were raised with regard to the finer bands of the nineteen-band plate before they were resolved; and the appearan
Knight's Mechanical Encyclopedia (ed. Knight), R. (search)
can therefore pass the other, though they may come into contact. Each pair of pistons has its independent shaft, and externally to the cylinder each of these shafts carries an elliptical gear-wheel, which works into an equal and similar wheel upon a shaft parallel to the piston-shaft. This second shaft, which is the working shaft, has a fly-wheel regulator. Steam is admitted between the sector-shaped pistons, and the motion is produced by the preponderance of leverage at the time. See Dr. Barnard's Report, pages 87-93. s s′ s′ are three views of Behren's Exposition engine, American. The views show three positions of the pistons which work in apposition. It has two cylinders, whose spaces overlap each other, and in the center of each is a solid cylindrical core. Each piston is firmly attached to an axis, and is part of a solid ring fitting to the core and to the interior of the cylinder. The axes are externally connected to gear-wheels to insure simultaneous and equal action
Knight's Mechanical Encyclopedia (ed. Knight), T. (search)
a given pitch an analogous process is pursued. Tiemann's tonsil instruments. An instrument of this kind, invented by the late S. D. Tillman, for illustrating visibly the theory of musical scale and of musical temperament, is described in Barnard's Report, French Exposition, pages 471-478. The auditory capacity of the human ear appears to range over about 12 octaves; the gravest audible note representing about 15 vibrations, and the most acute 48,000 per second. This capacity varies of1875. 3,163, of1866. Ty-po-graph′ic ma-chine′. One in which the depression of keys operates type in the proper succession to impress a matrix, from which a stereotype plate may be cast. Sweets's machine is described and figured in Dr. Barnard's Report of the French Exposition of 1867, pages 443-448. It resembles a parlor-organ in appearance, having in front one or more banks of keys, the number corresponding to the number of sorts to be employed in the work. Flamm's typographic