3475
OFFICIAL DESCRIPTIVE AND ILLUSTRATED CATALOGUE.
over the river Tees. Scamozzi , “ Del Idea Archi,” pub-lished 1015, conveys some notion of these structures; butBernouilli first explained their true principles. TheUnion Bridge over the Tweed, 449 feet span, constructedby Captain Sir S. Brown in 182b, was the first large bar-chain bridge erected in Britain . The Newhaven andBrighton suspension piers were also erected by the sameengineer. The great bridge by Telford across the MenaiStraits is 570 feet span; it was commenced in May 1819,and completed in December 1825. The HammersmithBridge, 422 feet span, by Tierney Clark , was completedin 1824. The Montrose Bridge, by iiendel, 412 feet span,was erected in 1829; and the Iluugerford Bridge, overthe Thames, G7G^ feet span, by Brunei , was built in 1844.The wire-rope bridge at Frieburg is 820 feet span. Theroadways of suspension bridges must not merely be hungfrom the chains, but be rendered stiff to resist the undu-latory motion caused by the wind.—See Minutes of Pro-ceedings of the Institution of Civil Engineers, February1(1, 1841, on this subjects—S. C.]
[The antiquity of suspension iron bridges is proved bytravellers in India and Thibet , who have seen them therein construction much resembling our own; in one instancethe chains which support a bridge of bamboo were raisedover stone piers, with openings through them whichadmit to the gangway.
It may not be uninteresting to know that the Frieburgsnspension bridge was constructed by M. Challey, aFrench engineer, that it cost only 24,000/., and that evenwith a considerable portion of the iron imported fromEngland : the wire was drawn at Bienne , from iron forgedin the Canton of Berne.—W. C. A.]
335 Carrington, F. A.—Designer and Producer.
Models of 3,000 square miles of England, showingportions of Leicestershire, Yorkshire, Nottinghamshire ,Derbyshire, Chester, and Lancashire , part of the port andtown of Dundee, and illustrating the peculiar featuresof these parts of the country. (Placed in the MainAvenue West.)
[Model maps are, as the name indicates, in relief, andare formed out of some plastic substance, such as plaster ofParis, papier-mache, or gutta pcrcha, which can be easilywrought or pressed into a mould, and becomes hard whendry or cool: they afford a means of becoming acquaintedwith the true features of a country, to which no othermode of representation is equal.—W. C. A.]
*S00<3<!
Class VI IT.
NAVAL ARCHITECTURE, Ac.
173 Penricu, Lieut., Royal Engineers—
Inventor and Proprietor.
Model of the stern of a vessel, with a new propellerand machinery, the object being to obtain a more directreaction, less slip, and greater velocity of stroke. Regis-tered April 1851.—Plate 305, p. 347.
223 Drank, Adams, & Dkank, Km; William Street,London Bridge —Manufacturers and Inventors.Revolving pistol, invented and patented by Mr. RobertAdams.
The principle of revolving chambers to pistols of onebarrel is not new; but it was not until tbe application ofpercussion powder to effect their discharge that revolvingor repeating fire-arms have been rendered practicallyuseful.
The pistol, of which the accompanying plate is an illus-tration, is made of three sizes; the largest or holster sizeis 10 inches long in the barrel, including the cylinder; thebore 38 balls to the lb., and weight 2 lbs. 14 ounces. Thenext size is 8 inches in length, 54 balls to tbe lb., andweighs about 2 lbs. Tbe smallest or pocket size is (1 incheslong, 120 balls to the lb., and weighs about 18 ounces. Thebarrel and frame are forged out of one single piece of thebest malleable iron, called “ Marshall's iron,” the squareframe being cut out to admit the revolving cylinder.This square frame gives great strength to tbe wholepistol, and affords a receptacle for nearly all the mecha-nism required in working it. The cylinder contains fivechambers, which are bored two sizes larger than thegauge of the barrel, in consequence of which, the ballhaving to pass through the diminished aperture of thebarrel, is forced into the grooves of the rilling, windageis thereby prevented, and great accuracy and strength ofshooting obtained. The chambers terminate at the breechend in a blunt cone nearly hemispherical, and tbe nippleis screwed into tbe back or apex of the cone so as to pro-duce a direct central fire.
One of the most important features of this pistol is itsmode of action, every movement being simultaneous andperformed by the trigger alone. It rotates the cylinder,raises the hammer, locks the chambers, and as each re-volves in a straight line wdtli the barrel discharges theshot. By this arrangement the liability to accident ismuch lessened, as the cap is not in a position to be struckby the hammer until the aperture of the cylinder is in adirect continuous line with the barrel.
There is no ramrod required in loading; the powderbeing put into each chamber from a flask, and a spherical orconical bull with a wad attached, pressed down upon thepowder with the finger. 'The ball is cast in tbe mouldwith a short tail, or “tang” of lead, which, on beingpassed through a small hole in the wad, is riveted to itby a slight blow.
On the left or near side of the frame is a stop spring,which on being pressed in, when the hammer is held asit were in a position of half cock and then allowed tofall, keeps the striking part of the hammer from project-ing through the frame upon the nipple, thus allowing thecylinder to rotate freely when in the act of loading; andby drawing the revolving pin (which lies under thebarrel) towards the muzzle, the cylinder may be removedimmediately, and any number of cylinders, ready loaded,may be substituted one after another, so that, if desired,a hundred consecutive shots may be discharged.
All the parts of these revolvers, with the exception ofthe hammer, trigger, and springs, are made by machinery;the circular parts turned, bored, and rilled ; the squaresurfaces planed, and the apertures in the frame slotted.The cylinders, after being polished, are engraved and case-hardened ; the barrel and frame are polished, engraved, andblued; tbe main spring is inserted into the stock, and thesear and trigger spring into the frame; thus all the work-ing parts are enclosed and protected from wet or injury,which make it scarcely possible, when properly adjusted,that any portion should get out of order.
Every pistol is proved at the proving-house, and has12 rounds fired from each chamber (making GO shots)before it is sold to the public.
Tbe accuracy of shooting, particularly at long dis-tances, is remarkable—12 to 15 paces being usually con-sidered the maximum distances at which anything likeaccuracy could be arrived at; but with these revolversevery shot is certain at 50 yards at a 30-inch target, andequally so at 100 yards at a G-feet target. The hannnei'or cock being behind the frame, and below the level ofthe barrel, the sights and aim are in no way interfered with-
Rifles and carbines are made on the same principle, andat from 300 to 500 yards are equally effective.
The wadded ball, of which an illustration is given, >sfound to be an excellent substitute for the Delvigne o*Minic ball: its flight invariably points forward.
On tbe same plate is a mode of rifling also patented byMr. Adams, showing three ridges instead of grooves, anddividing the barrel into a sort of triangular ellipse, gome-