462 Class 10.— PHILOSOPHICAL, MUSICAL, HOROLOGICAL , [Unit^
North, North Central, and South Central Galleries.
Surface electro-magnet, consisting of a thick piece ofwrought iron, enveloped by a bundle of copper wires.Armature to the same. A battery of moderate powerproduces such a powerful attraction between the electro-magnet and its armature, that a weight of more than oneton has to be applied in order to draw them asunder.
[The peculiarity of the former electro-magnet, which isadapted for diamagnetic experiments, the magnetization ofsteel bars, &c., consists in the great comparative breadthof the iron core, by means of which the full effect of thecoils of wire is secured, even in the case of their beingremoved to the distance of one or two inches from thesurface of the iron. The form of iron adopted admits ofa much greater quantity of electro-magnetic coils, andconsequently of a much greater magnetic effect, thancan be obtained from the usual cylindrical shape.
The peculiarity of the latter, or surface electro-magnet(which is the first of the kind ever constructed), consistsin the comparatively great surface of contact which itpresents to its armature. The principle of its construction,and of that of others of its class subsequently constructedby the exhibitor and other parties, is derived from thelaw of electro-magnetic action discovered by the exhibitor,viz., that the maximum attractive power of an electro-magnet for its armature is about 300 lbs. for each squareinch of transverse section of the magnetic circuit.]
441 Waite, George, 2 Old Burlington Street —Inventor.
Electro-galvanic apparatus for the teeth, furnishedwith a platinum point, safety key, elevators, forceps, andother instruments used in dental surgery.
Set of teeth with gold jewelled blocks or masticators.Sets of electro-gilded teeth, fitted with novel blocks formastication.
Six other pieces, with pearl blocks and plates.
444 Westmoreland, John, Derby —Designer.
Patent gutta-percha electrical machine.
446 Green, Samuel, 7 Helmet Rom, Old Street—Manufacturer.
Various compasses and sun-dials. Damp detectors.Angle-meters. Ivory circular thermometers with compassor magnetic sun-dial. Miners’ compass, with sights, &c.
448 Bentley, Thomas, Margate.
A pair of carpenter’s compasses, with improved springjoint.
450 Weight, Samuel, 14 Burton Street, Cheltenham —
Inventor and Manufacturer.
Model of a machine for expelling fire-damp out of coal-pits, and foul air out of wells, brewery vats, or otherplaces where they collect. Provisionally registered.
451 Palmer, W. V., Somers Town —Producer.Electrotypes, and engravings from electrotypes.
452 Crichton, John, 112 Leadenhall Street —
Manufacturer.
Solid arch sextant, with improved reflector to vernier;double-limb sextant; 4-inch sextant; box sextant; coast-surveying sextant, as made for the Trinity yachts; ebonysextant.
Quadrants, plain and with tangent screw to index, andwith tangent screws to index and horizon. Quadrantswith spring vertical adjustment, and with two and threeback shades to horizon. Quadrant, with handle, tele-scopes, and mahogany case, divided to 30 seconds.
Azimuth compass, prismatic, large and small sizes.Sympiesometer; marine barometer; artificial horizon,with iron bottles and improved iron trough.
Gravatt’s levels, bronzed and brigh t; 5-inch theodolite.Naval telescopes, 3 feet and 2 feet, with signals. Achro-matic night-glass; day or night telescope; gunner'squadrant with level; gunner’s callipers, large and small; j
453 Knight, George, & Sons, Foster Lane —Manufacturers.
Commercial chemical cabinet. . g
Urino-chemical chest, containing all the instrume 'and reagents necessary for a chemico-pathological eNmination; designed by Dr. Venables. . . {
Portable universal chemical furnace, on the princip| e .Dr. Black. It is constructed of stout sheet-iron, l' nwith fire-bricks; it is suited for the reduction and ess.7of metallic ores, cupellation of the precious metals,filiations of every kind, decompositions of substances 1passing them through heated media, and for nearly eve 7operation for which a furnace is required. With sa"baths, stoppers, crucibles, muffles, tongs, &c.; alsoimproved hood by the aid of which noxious fumes ansi fcfrom evaporations pass readily into the flue of the f lirlia ,v.[Portable essay furnace and apparatus, adapted for *use of mining companies. , e
Various blowpipes, and blowpipe apparatus, for texamination of minerals on a small scale. n
Patent improved air-pump by which a good vacuum e®be obtained in a short time. Invented by Mr. C. ’Siemens. The air-pump consists of two cylinders differ' bin magnitude, of which the smaller is on the top of 'larger, while the valved pistons belonging to each r J s P®L .ively, are attached to the same piston-rod. Thewithdrawn from the receiver or other vessel intendedbe exhausted is condensed in the upper cylinder into ofourth part of its original volume, and, consequent Palways possesses sufficient elasticity to pass throughdischarging valve and escape into the atmosphere, 'opposing pressure of which on that valve is thus countsacted in a novel manner.
Plate electric machine, on Woodward’s arrangement.Galvanic battery; Professor Daniell’s arrangement, cosisting of a series of six cells; each cell comprises a c °PP 0 pcylindrical vessel, to be filled with a solution of sulphate^copper; in the centre is a porous tube containing a" amgamated zinc rod, and filled with dilute sulphuric aci ■Galvanic battery ; Professor Groves’ arrangement,sisting of a series of six cells, each cell being a g ^vessel containing an amalgamated zinc plate, to be n ^with dilute sulphuric acid, having in the centre aporous cell containing a platinum plate, and filled wnitric acid. ■ctin' r
Galvanic battery; Alfred Smee ’s arrangement, cons' £of a series of six cells, each cell being a glass v ® sse t ,]a-contain dilute sulphuric acid; to each cell is fitted a P^_tinised silver plate, having on each side of it an. ama c “ n .mated zinc plate: the whole of these plates being .jynected in series to one rod or bar, they can be rearaised from or lowered into the exciting liquid. . . 0 fGalvanic battery ; Maynooth arrangement, consisting ^a series of ten cells, each cell being a cast-iron tro%, . gbe filled with dilute nitric acid, in the centre of w ; UL aU da porous cell containing an amalgamated zinc plate, >charged with dilute sulphuric acid. ce ]]s
Galvanic battery, for telegraph purposes; the jtJjformed of gutta percha, filled with sand saturated. ^
dilute sulphuric acid; each cell containing a copP elamalgamated zinc plate. . ngi" e ’
Working model of an electro-magnetic motive e gbeing a modification of Dr. Bitchie’s arrangement. . CjWorking model of an electro-magnetic motive eifebeing a modification of Bain’s arrangement. . , o0 n-Improved electro-magnetic coil machine, w 'tductors, &c., for medical purposes. _ , . j, tl' e
Larger and more powerful instrument, in w fI . 1 .primary or secondary current can be applied, W1batteries, water-regulator, conductors, &c. _ „ a pj-i-
Arrangement of the coil machine, consisting 0 p on tactmary and secondary coil in a vertical position. , ^ | U u'is broken and renewed by the rotation of a ®°* t; ~ U c i; !l tclymounted between two brass pillars, situated inline j e 0 fover the axis of the coil in which is placed a nu seSiron wires. The electric current from the battery I