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EXHIBITION, BRITISH INDUSTRIAL. 



ing over or around permanent magnets. "When 

 a current is sent, second by second, from a con- 

 trolling 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 com- 

 pany also sent the Acoustic Telegraph, the sig- 

 nals being produced by strokes on a pair of 

 bells of different tones. 



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 but one 

 movable piece, the hammer which strikes the 

 bell. The battery employed is a one-fluid-bat- 

 tery, the negative plate being platinized graph- 

 ite. A counting index is attached to some 

 bells to count if the signalman is absent or dis- 

 tracted. 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 ; an audible system of Train Signals ; 

 an index for counting, and an apparatus for re- 

 cording them. 



Messrs. C. and S. A. Yarley exhibited a large 

 ebonite Electrical Machine : the disc is three 

 feet in diameter, and is excited by a soft amal- 

 gam composed of zinc, tin, mercury, and lead, 

 to give out sparks from 16 to 20 inches in 

 length. 



SURGICAL INSTRUMENTS AND APPLIANCES. 

 All the well-known manufacturers of Great 

 Britain were represented in the Exhibition. 

 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. The power here is 

 obtained by an endless screw, and is so great 

 that no part of the frame except the bones is 

 capable of withstanding its force. As it cuts 

 in a slightly uneven manner, and the constric- 

 tion is necessarily very great before incision 

 commences, there is little chance of important 

 hemorrhage happening after its employment. 



The Artificial Limbs shown by Masters were 

 of exquisite workmanship. One of the artifi- 

 cial legs was of wonderfully small weight viz., 

 2 Ib. 7 oz., constructed of -willow wood coated 

 with leather, and furnished with strong though 

 light articulations. 



Among the French exhibitors, Charriere in- 

 vented for M. Roger, the celebrated tenor of 

 the Opera 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. In the French gallery we also noticed 



the apparatus of Dr. Sales-Girons for the Pul- 

 verization 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 was 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. 



Leiter, of Vienna, had tubes used after the ope- 

 ration of tracheotomy ; they 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 devised immersion in 

 tepid water, constantly changing and was 

 quite successful in his treatment. 



SANITARY APPLIANCES. Mr. Thomas Spencer 

 exhibited the Magnetic Purifying Filter the 

 discovery is, that magnetic oxide of iron, load- 

 stone, is nature's chief agent of purification, 

 and that any stratum containing iron also con- 

 tains a small percentage of this oxide; and 

 that where the oxide most abounds, water is 

 purest. The oxide attracts oxygen ; the mole- 

 cules of that gas become polarized, or ozone ; 

 the latter attracts the carbon of moist organic 

 matter ; and carbonic acid results. 



Dahlke's patent Silicated Carbon Filter, is 

 formed of a combination of carbon with silica, 

 as existing in the Torbane Hill mineral, which 

 is represented as immensely more effective than 

 mere carbon, both as an oxidizer and a pro- 

 moter of chemical combination generally : car- 

 bon, indeed, acting mainly by absorption, or 

 not chemically, being subject to saturation, and 

 absorbing the carbonic acid. Instead of taking 

 away the gas, the silicated carbon causes pro- 

 duction of it, whilst nitrogenous products be- 

 come changed. These filters have been adopted 

 by the Metropolitan Free Drinking Fountains 

 Association. 



MUSICAL INSTRUMENTS. The Pianoforte is 

 given to outside decoration. This Exhibition 

 shows, in its ample display of woods hitherto 

 unknown from every quarter of the globe, what 

 exquisite varieties of color and grain lie at the 

 service of every cabinetmaker, though he be 

 bent on no such fine fancies. Meanwhile, the 

 general quality of instruments is improved. 



An American improvement merits special 

 mention. Mr. Hulskamp exhibited a modifica- 

 tion of the instrument, founded on the observa- 

 tion that tension was an important element in 

 the vibratory action of bodies. Accordingly, 

 applying, by the use of screws, a straining 

 power to the sounding board of a pianoforte, 

 he is enabled to increase his vibration so mate- 

 rially, that a horizontal pianoforte exhibited 

 by him, two feet shorter than the ordinary 

 grand, has all the power of the larger instru- 



