478* Class 10.—PHILOSOPHICAL, MUSICAL, AND HOROLOGICAL INSTRUMENTS, &c.North, North Central, and South Central Galleries.

7. Another form of the same alarum.

8. Plan proposed by G. Little for sounding a bell bythe self-action of an electro-magnet.

Disc Telegraphs.

1. Disc telegraph: the signals given by the step-by-step rotation, and pausing of a disc bearing letters orfigures. The rotation produced by the action of anelectro-magnet. Wheatstone and Cooke’s patent of 1840.

2. Disc telegraph: the letters or figures pointed out bythe rotation and pausing of an index or hand operatingby electro-magnetic action. Patent of 1840.

3. Disc telegraph : similar to No. 1, except that signalsare given by numbers.

4. Modification of the disc telegraph proposed by Nott.

5. Disc telegraph: the communicator, or signal-givingapparatus being conjoined to the instrument.

6. Modification of the disc telegraph arranged for acounter, or register of any successive movements oractions, such as persons passing through a door or gate,strokes made by a steam-engine, fly or other press, &c.

7. Magneto-electric communicator for the disc tele-graphs : no battery is required, a permanent magnet fur-nishing a constant series of induced currents by therotation of an armature and coils over its poles. Wheat-stone ’s patent of 1841.

8. Second form of the magneto-electric communicator,adapted to work disc telegraph, giving signals by numbers.

Double Index Disc Telegraphs.

1. Double index disc telegraph: the two hands moveindependently, so that one may be set to give any re-quired permanent signal, while conversation is carried onby the other. This instrument was arranged for workingthe atmospheric machinery on the South Devon Eailway.It requires one wire only. Hatcher’s patent of 1847.

2. Double index disc telegraph. The two hands re-volve step by step in opposite directions. They wouldtherefore indicate exactly at all stations on a single linethe progressive movement and approach of two trainsrunning in opposite directions. Patent of 1847.

3. Single index disc telegraph. The index can bemade to rotate in either direction, so that the speed ofsignalling would be increased by the facility with whichany position could be given to the index by a few move-ments. Patent of 1847.

Printing Telegraphs.

1. Elective magnet printing telegraph. The signals areprinted in ordinary type, according to the first arrange-ment of Wheatstone in 1841. The current when sent inone direction moves the type wheel to the requiredposition, and when reversed brings into operation theprinting machinery. Hatcher’s patent of 1847.

2. Second form of the elective magnet printing tele-graph. Patent of 1847.

3. Third form of the elective magnet printing telegraph:the signals being printed not in type but in combinationsof dots or points.

4. Type printing^telegraph: the type wheel, after eachsignal is printed, is released from the machinery andregains its zero or quiescent position at one bound, therebyincreasing the correctness of the operation by making

each signal wholly independent of the correctness orcorrectness of the preceding one. Barlow and Forsteipatent of 1848.

5. Chemical printing telegraph: signals given by, | Vor spots arranged in two lines. The marks produced oythe chemical action of the current on a prepared paper-Alexander Bain ’s patent of 1846.

6. Chemical printing telegraph: signals given by doand lines combined in various ways. Bain ’s patent o1846.

Magneto-electric Machines.

1. Magneto-electric machine. Currents induced by thepermanent magnet can be sent in one direction by tWmachine. It is used for the sounding of alarums. Abattery is required. Wheatstone ’s patent of 1841.

2. Magneto-electric machine for sending currents t

either direction at pleasure. Used for working the doubiindex telegraphs. Hatcher’s patent of 1847. r

3. Induced current machine: an inducing battery ®

small power is used with this form of machine. It s ?Bycurrents in either direction like the last. It was usedworking the double index telegraphs on the South Devonline. Patent of 1847. j

4. Second form of induced current machine: arrang e .°for working with the code of signals in use by the Adm 1 'ralty. Patent of 1847.

Galvanometers.

1. Indicator or galvanometer in which the magnet^needle is replaced by a magnetised steel disc. Mappl epatent of 1847.

2. Simple current director for causing the current t^ring either of two bells or to actuate either of two instm -ments.

3. Simple current director for ringing either of tv 0

bells as for an office. ,

4. Current director, for causing the current to souneither of three bells, or actuate either of three instruments-

5. Current director or switch for a line of telegraP

with two wires to any one of three other lines of ■„telegraph. Switches of this kind are extensively used 1England. ,

6. Punch or stamp used for cutting out in paper tnsignals or combinations of dots and lines to be tra® ^mitted by Bain’s chemical telegraph. Bain ’s patent

nting

1846.

7. Stick or rule of type used with Bain ’s prin°telegraph. i

A series of insulators of various forms construeunder Cooke and Wheatstone ’s, Ricardo and Clark’s, aMapple’s patents.

750 Tracy, W. M., 13 Hill Street, Berkeley Square-Bullet extractor.

751 Airey, Thos., 67 Dale Street, Liverpool —

Manufacturer. - s

Newly-invented sunk centre seconds watches. g

invention admits of the seconds-hand beating dead. j

seconds-hands may be applied—one from the centre,the other in the usual place.

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