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ELECTKICITY. 



ter of a millimetre thick, was rendered incan- 

 descent for a few moments, and the voltaic arc 

 was also obtained. M. Plante remarks upon 

 this that it is not, as in the case of induction, 

 the direct production of one physical effect by 

 another physical action ; but the final result is 

 none the less an accumulation or a modification 

 of electrical force, which can be utilized under 

 certain circumstances. (Mechanics' Magazine.) 

 An Electric Piano. M.. Spies, of Paris, has 

 invented an electric piano, which has been ex- 

 hibited at a meeting of the " Societe" d'Encou- 

 ragement," and elicited great surprise and 

 admiration. The electrical arrangement con- 

 sists, in the interior of the piano, of a 

 series of electro-magnets, which act upon the 

 hammers that strike the wires. These ham- 

 mers communicate in the ordinary way with 

 the keyboard, but on their opposite side they 

 have small wooden rods, terminating with 

 armatures, which are attracted to the elec- 

 tro-magnets whenever they become active. 

 The "directing organ," as it is called, is con- 

 structed as follows: First, there are two 

 wooden rollers, with an intermediate roller of 

 metal. The paper, specially prepared with a 

 series of holes, placed in positions representing 

 the several notes of music, is rolled around 

 one of the wooden rollers ; passing over the 

 metal roller, it is drawn off and wound around 

 the second wooden roller. This unwinding 

 keeps it always at a uniform tension. Second, 

 a clockwork movement gives motion to the 

 rollers. Third, a small keyboard, with mov- 

 able copper hammers, is placed above the 

 intermediate roller, so that the heads of 

 the hammers rest upon the paper band (pre- 

 pared as described) which represents the mu- 

 sical notes. The battery is a series of thirty- 

 six Daniell's cells. One pole of the battery 

 connects with the small keyboard ; the other, 

 through the various electro-magnets of the 

 piano, with the metallic roller. The rollers 

 being set in motion by the clockwork, cause 

 the prepared band to be unrolled and pass on 

 the metallic roller. "Whenever a hole in the 

 paper comes under the keyboard, the lightly- 

 resting hammer at once makes contact, a cur- 

 rent passes through to the electro-magnet, 

 which attracts the hammer, and the required 

 note is struck ; and so, from a series of these 

 prepared holes a number of successive electric 

 contacts are made, acting upon the several elec- 

 tro-magnets, causing the various hammers to 

 strike the required notes. The principle of the 

 piano is really that of automatic telegraphy, 

 except that, in transmitting messages automa- 

 tically by the ingenious apparatus devised for 

 that purpose, the result is a permanent and 

 visible record; whereas, in the case of the elec- 

 tric piano, the result is simply one of sound. 

 The electric current being uniform throughout, 

 produces a uniform blow with all the ham- 

 mers; but, by the application of pedal and 

 sourdines, M. Speiss causes any music to be 

 played with the required expression. 



Magnetic Alphabetical Telegraph. Rev. H. 

 B. Wilde, of Reading, England, has invented 

 a new magnetic alphabetical telegraph. The 

 sender has a dial plate, inscribed with the let- 

 ters of the alphabet and other signs. This 

 has a jointed handle, which may be quickly 

 moved round the dial, and may be checked at 

 any point, by a ratchet. The instrument upon 

 which the messages are received has a smaller 

 dial, traversed by a delicate indicator hand. 

 The movements of the handle by the sender 

 of a message are accurately reproduced on the 

 index plate at the other end of the line, and 

 may be easily read. A series of permanent 

 horseshoe magnets furnishes the power. These 

 are united to form a compound magnet, to the 

 north and south poles of which are fixed, ver- 

 tically, independent electro-magnets, their up- 

 per ends being inserted through holes in a brass 

 plate, and planed off so that the iron and brass 

 present one smooth, flat, surface. The handle 

 employed in sending messages gives motion to 

 a thick, circular piece of soft iron, which is sup- 

 ported above the compound magnet by a suit- 

 able socket-piece. The edge of this plate is di- 

 vided into twenty-eight equal spaces, which are 

 alternately notched out right and left, so that 

 there are fourteen projections or teeth and the 

 same number of corresponding spaces. The 

 iron plate in its rotary movement lightly rubs 

 the brass plate through which the ends of the 

 electro -magnets are inserted, and as the pro- 

 jections and spaces at the edge of the plate 

 alternately pass over these ends, positive and 

 negative currents are excited in the insulating 

 wire surrounding the electro-magnet. The 

 currents being conveyed to the receiving in- 

 strument induce rapid changes in the polarity 

 of an ordinary electro-magnet, between the 

 poles of which a small permanent magnet 

 vibrates; each vibration liberating the teeth 

 of an escape-wheel propelled by a very light 

 train of clockwork wheels and mainspring. 

 The axis of the escape-wheel carries the hand 

 or index of the dial. Thus, as the sender 

 moves the handle over the letters on the dial, 

 positive and negative currents are alternately 

 induced in the conducting wires, which cur- 

 rents cause the hand of the receiving instru- 

 ment to pass over the same letters. 



Electric Apparatus for Blasting Purposes. 

 A new dynamo-electric apparatus, especially 

 adapted for blasting operations, the invention 

 of Mr. 0. W. Siemens, is described by the 

 Mechanics' 1 Magazine. It is an adaptation of 

 the larger machine contrived by him for the 

 conversion of great mechanical force into 

 dynamic electricity (see ANNUAL CYCLOPAEDIA 

 for 186T). The essential difference between the 

 Siemens apparatus and that of Wilde is the 

 absence, in the former case, of the magneto- 

 electric machine as the exciting agent. An 

 electro-magnetic machine is alone employed, 

 having as its exciting agent its residuary mag- 

 netism only. The electro-magnet is provided 

 with a magnet-cylinder, within which revolves 



