the instruments for receiving and recording the liberated current, which latter was conducted thither by a line of copper wire laid along the Building between those instruments and the turnstiles, and metallically connected to each. The registers thus obtained formed a complete check upon the money taken at the doors, and they were produced automatically, requiring only the current evoked by the revolving turnstile to set in motion the electrical apparatus whereby they were recorded.

The wires of the Electric and International Telegraph Company had their stations in the Building, whence messages could be sent to all the telegraphic stations of the world.*

In illustration, as well of the pure science of electricity, as of its telegraphic offshoot, there were in all sixty-eight exhibitors, whose nationalities may be summarized as follows:-Twenty-nine British subjects, fourteen French, five Austrian, five Dutch, five Belgian, four Italian; and two each from Switzerland, Prussia, and Denmark respectively. Their productions were more remarkable for careful manufacture than for novelty or originality.

First, the Gutta Percha Company exhibited two frames, wherein was pure gutta percha, rolled out to a tenuity little less than that of a soap-bubble, and stretched like a picture glass. The surface was perfectly even, and quite diaphanous, being infinitely less opaque than horn such as is used in lanterns. The same Company also exhibited good specimens of insulated conductors ranging from a thickness suitable for a 2000-mile cable, down to a size small enough for surrounding the coils of electro-magnets. One mile of this latter beautiful thread is contained in a ball about the size of an ordinary breakfast-cup. We had also numerous other specimens of "cores," or insulated centres of cables, of which the Company showed fifty-one specimens, being separate examples of each of the cores manufactured by them since 1850.

Glass, Elliott, and Co. similarly displayed specimens of thirty cables which they have completed from cores made by the Gutta Percha Company, and submerged by their own staff.

The great improvements and numerous inventions in Electric Telegraphy during the past ten years were strikingly shown by the various new instruments exhibited by the Universal Private Telegraph, the British and Irish, the Submarine, and other Telegraphic Companies. Prof. Wheatstone's ingenious and beautiful Domestic Telegraphs were shown in working order, and many inventions and contrivances to utilize this valuable discovery were

*One of the excluded companies (the Submarine) determined not to be beaten, having hired a piece of vacant ground in the Cromwell-road, nearly opposite the south-east tower, and erected thereon a gay little Kiosk-like building, supplied internally with all the requisites of a telegraph-office. Into this were brought the Company's wires, which, in connexion with their own cables and with the wires of the Magnetic Telegraph Company, were thus in communication with all the British and Continental stations. From this position, defiant with international bunting, they were enabled to wage vigorous competition with their privileged rivals, apparently not without success, for the large amount of telegraphic business evoked by the occasion. -Mechanics' Magazine.

to be seen in this Class. Mr. Tyer exhibited his patent Train Telegraph which has met with the strong approval of Captain Tyler and Colonel Yolland, of the Board of Trade. The apparatus for the use of the signalmen comprises a telegraphic-needle for each line of rails in each direction, and a bell and gong, having different sounds, the one for the up and the other for the down line of rails in each direction. The bell or gong is used to draw attention to the approach or passage of a train, and by the number of beats employed, to describe the train: while the needles are used solely to denote either "line blocked," or "line clear ;" and no signalman can alter his own instrument, it being the duty of each signalman to work the needles of the signalmen on each side of him.

The most interesting and advanced of these instruments were those which worked more or less automatically. The Automatic system of Mr. Allan is especially ingenious. It consists of three machines; the punching-machine is the first of these, and by this the ribbon paper to be passed through the sending machine is perforated with holes, representing dots and strokes of the Morse alphabet, at those points only where the current is required to mark on the unperforated ribbon at the receiving station; next is the sending-machine, into which the perforated paper is introduced. This machine winds up its own clockwork, whereby the paper is drawn forward, and stops of its own accord when the message is completed; and lastly, the receiving-instrument at the distant station, which is also so arranged as to start its own machinery on receiving the electric impulse, and stop it when the perforated paper at the other end has passed through the sending apparatus. Professor Wheatstone's Automatic Recorder was another very beautiful instrument of this class. M. Sortais exhibited a remarkable machine, whereby the ordinary Morse instrument can be made to start and stop itself by the electric current. Signor Bonelli showed in actual work, his ingenious Electro-chemical Recording Apparatus.

In Printing Telegraphs, the only instrument exhibited was that of Mr. Jacob Brett, which is memorable historically, as the instrument by which the first message was received through the first submarine cable.

The British and Irish Magnetic Telegraph Company exhibited an ingenious and novel system of controlling turret and other clocks, patented by Mr. L. Jones, of Chester, unlike any previously in use; the clocks being controlled only, and not moved either in whole or part, by electricity. The three clocks shown were in all respects, excepting the pendulum, of ordinary construction, and would go without the electric current, keeping their own time. The pendulum is a hollow electro-magnet, oscillating over or around permanent magnets. When a current is sent, second by second, from a controlling clock, the temporary attraction between the electro-magnet and the permanent magnet compels the controlled pendulum to copy the vibrations of the controller,

even though there may be a discrepancy of several minutes in their daily independent rates. The above Company also sent the Acoustic Telegraph, a clever and extensively used instrument, invented by Sir Charles Bright and Mr. E. Bright. By its means a telegraph clerk, in taking off a message, writes it himself without being obliged to raise his eyes from the paper; the signals being produced by strokes on a pair of bells of different tones, one placed on either side of his writing-desk. There was also a Transmitting Relay, patented by the Messrs. Bright, for use in connexion with a needle telegraph, by means of which the taking off of a message at an intermediate station is rendered unnecessary, extra battery power being used instead. We also noticed a rarefied-air Lightning Protector, patented by these gentlemen.

Mr. C. F. Walker, the telegraph engineer, exhibited a pair of the bells, of which some hundreds are erected on the South-Eastern Railway, for signalling trains. There is no mechanism, and but one moveable piece, the hammer which strikes the bell. The battery employed is a one-fluid battery, the negative plate being platinized graphite. A counting index is attached to some bells to count if the signalman is absent or distracted. Two instruments record the [signals. One of these drops black and white balls into a groove for the signals, and spotted and blue for the hours and quarters. The other imprints red and black marks on cotton thread for the signals, and the two combined for time marks. Mr. Walker also exhibited a Graphite Battery in work, remarkable for its simplicity of action, and the constancy of the power evoked; an audible system of Train Signals; an index for counting, and an apparatus for recording them.

The two Electrometers, portable apparatus for observing atmospheric electricity, and recently introduced by Dr. Thomson into the observatory at Kew, were shown with Mr. C. F. Varley's Multiplying Electrometer for testing the electrical state of the atmosphere when its power is too weak for ordinary instruments. Messrs. C. and S. A. Varley exhibited a large ebonite Electrical Machine: the disc is three feet in diameter, and is excited by a soft amalgam composed of zinc, tin, mercury, and lead, to give out sparks from 16 to 20 inches in length. Some Voltaic Piles and other electrical objects were exhibited by the University of Pavia, as having once belonged to the immortal Volta.

SURGICAL INSTRUMENTS AND APPLIANCES.

The numerous and important display of Surgical Instruments in the Exhibition was subdivided into those used, first, for general surgical purposes; secondly, in ophthalmic surgery; thirdly, in orthopedic surgery; fourthly, in aural surgery; fifthly, in dental surgery; and, sixthly, in obstetric surgery.

In excellence of workmanship and perfection of manufacture,

the English makers still maintain their superiority; but Prussia, Russia, and France tread very closely on the steps of advance taken by some of our leading makers.

All the well-known manufacturers of Great Britain were represented in the Exhibition. Evans and Stevens, Weiss, Savigny, Coxeter, Ferguson, Matthews, Durroch, Bigg, Ernst, Ash and Co., and a host of others more than maintained their previous reputation. Evans and Stevens exhibited an ingenious Trephine, which possesses some advantages over that ordinarily in use; and a new instrument for Vaccination. Weiss and Son exhibited among the novelties a modification of the Ecraseur, an instrument by means of which the tissues of the body can be divided by a wire or chain saw, worked by a sort of windlass action. In that devised by Messrs. Weiss the power is obtained by an endless screw, and is so great that no part of the frame except the bones is capable of withstanding its almost resistless force. As it cuts in a slightly uneven manner, and the constriction is necessarily very great before incision commences, it follows that there is little chance of important hæmorrhage happening after its employment; it is therefore preferable to the knife for some operations, such as removal of part or the whole of the tongue, &c.

Messrs. Savigny showed the instrument suggested by Dr. Marcet for the Resuscitation of those rendered inanimate by Drowning, Suffocation, &c. : it is very ingenious, and likely to be very useful.

A very serviceable Stretcher, and also an hospital-bed appliance invented by Captain Russell, were shown.

Savory and Moore exhibited some Medicine-Chests and Cases which are models of successful arrangement; and also Panniers for field purposes, which contain plenty of surgical instruments, drugs, and other appliances, and which, by a very simple contrivance, can be converted into a firm substitute for an operating-table. Mr. Rein had a small glass room, in the centre of which was an ugly chair, intended to collect sound by means of the open mouths of two heads, which terminate its two arms and communicate with the interior, so that we imagine the patient sits on something like a drum, the vibrations of which increase his powers of hearing.

The Artificial Limbs shown by Masters were of exquisite workmanship. One of the artificial legs was of wonderfully small weight -viz., 2 lb. 7 oz., constructed of willow wood coated with leather, and furnished with strong though light articulations. Notwithstanding its lightness, it is capable of bearing the whole weight of an adult man.

In Orthopedic instruments Bigg and Ernst maintained their deserved reputation. Appliances of this kind, which are devised for the cure or relief of spinal or other deformity, are now constructed on really scientific principles, and the problem of combining strength with lightness seems to have been solved in a great degree.

L

Among the French exhibitors Charrière, Mathieu, and Luër fully maintained their claims to merit in invention and originality of construction. Charrière invented for M. Roger, the celebrated tenor of the Opéra Comique, an Arm. The novelty in its construction consists of an extra joint made in the centre of the forearm, to which a spring, with cords, is attached; and, the cords passing over the opposite shoulder, give the wearer the power of turning the hand and pointing the finger. The object is, however, attained by an awkward, ungraceful movement, required to be made by the opposite shoulder to procure the movements of the hand and finger. This invention is, however, disputed by M. Mathieu. Luer's instruments for Operations on the Eye are of a very superior kind. In the French gallery we also noticed the apparatus of Dr. Sales-Girons for the Pulverization of Liquids: by means of compressed air a small stream of mineral or medicated water is driven against a metal plate with such rapidity, that on striking it, it breaks into a finely-divided state, or, in other words, into a mist which the patient can easily inhale. An instrument invented by Dr. Marey, that not only shows the Pulsation of an Artery by the oscillation of a lever, but also draws on paper the curve defined by it at each beat of the heart, merits a word of mention.

Mr. Grossmith, of Fleet-street, exhibited an Artificial Leg (not of cork, as generally supposed), well-formed, of finished proportions, with knee, ankle, and toe articulations, performing all the movements of the natural limb, and sufficiently durable to give the wearer many years of active service,-weighing only 2 lb. This artist has introduced a new principle of joint articulation, a kind of spring-rod passing down the calf of the leg, and connecting the actions of the knee and ankle, which effectually causes flexion of the knee; and, at the same time, gives a feeling of safety to the wearer quite equal to that secured by a bolted stop, and without its awkward appearance. Mr. Grossmith also showed Artificial Eyes, which were fine specimens of glass-working, especially for beauty of colouring. The tint of the sclerotica, with the minute veins running through it; the colours of the iris, its radiance, and the transparency of the cornea; are all obtained with the greatest accuracy; so that, when inserted under the eyelids the deception is complete, and the artificial eye cannot be detected from the natural one.

Desjardins and Boisonneau, of Paris, also exhibited Artificial Eyes, with the latest modifications of form and thinness of material.

Leiter, of Vienna, had some instruments which were really original. His tubes used after the operation of Tracheotomy have a valve which allows the patient to speak, notwithstanding the opening in his windpipe. Dr. Hebra's Bath, in which he keeps patients for such a period as eight weeks, is a curiosity in its way. He was first led to adopt this in a case of extensive superficial burn; and conceived that immersion in tepid water, constantly chang