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Southern Historical Society Papers, Volume 37. (ed. Reverend J. William Jones) 3 1 Browse Search
Knight's Mechanical Encyclopedia (ed. Knight) 2 2 Browse Search
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Knight's Mechanical Encyclopedia (ed. Knight), G. (search)
be set at any angle with the outer one, and rotation imparted by a string, when it will be found strongly to resist any attempt to turn it from the plane of its rotation. This disposition of a rotating object to maintain its revolutions in one plane, designated as fixity or persistence of the plane of rotation, may be farther illustrated by the tendency of a trundling hoop or rotating top to remain upright, and by the directness of flight of rotating projectiles. About 1832, Professor W. R. Johnston, of Philadelphia, devised an instrument which he termed a rotoscope, for illustrating this principle. He also showed the effect of rotary motion in overcoming the force of terrestrial gravity by the device shown at B, Fig. 2350. In this a disk is pivoted within a ring, its axis is extended and turned down, so that one end may be supported in a depression at the top of an upright standard. When the disk is placed vertically and rapid rotation imparted, it will maintain its rotat
Knight's Mechanical Encyclopedia (ed. Knight), R. (search)
d makes a steam-tight joint without the use of packing. Rotary steam-valve. Rotary valve for steam-engines. In Fig. 4478, the valves K L have each three wings; they oscillate in and coincide in form with the frustal chambers, whose ports connect with the steam-cylinder. The pressure on each valve is nearly balanced, and it is kept to its seat by a coil spring acting longitudinally on its stem. Ro′ta-scope. An instrument on the principle of the gyroscope, invented by Professor W. R. Johnston of Philadelphia, about 1832. See gyroscope. Rot′ten-stone. A soft, brown mineral, found in Derbyshire, England, and used as a polishing material. It is composed of alumina, 86; carbon, 10; silex, 4. It is sometimes called a variety of tripoli, but the latter is principally silex. Rottenstone is more nearly allied to emery, but has a portion of carbon and no iron. Iron is present in all the emeries. Rot′ting. The steeping of flax-stalks to soften the gum and loose<
Southern Historical Society Papers, Volume 37. (ed. Reverend J. William Jones), Affidavit of Supervisors of Co. C, 149th regiment. Pa. Vols. (search)
ustration of the rapid succession of stirring events during the whirlwind of battle, and the sudden changes of fortune from one side to the other. As a further confirmation of the above account, I will quote from Capt. Bond's letter to Comrade W. R. Johnston, secretary of our Regimental Association: Scotland neck, N. C., Nov. 29, 1901. W. R. Johnston, Belleview, Pa., Dear Comrade:—Yours of the 21st with stated enclosure to hand. I have read Capt. Bassler's address with very great inteW. R. Johnston, Belleview, Pa., Dear Comrade:—Yours of the 21st with stated enclosure to hand. I have read Capt. Bassler's address with very great interest. The more so for the reason that I was a witness in part, and I might say an actor in part of one of the incidents described, for I was the mounted staff officer who fired several shots at the Mississippian who captured your State flag. * * * * When I dismounted and picked up a musket there could have been nothing very formidable about my appearance for I was only a pale-faced boy, yet several of the wounded thought I was an inhuman monster, for with hands raised in a deprecating way they