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amplitude annunciator apparatus armature arranged articulate speech attached audible battery Bell telephone Bell's patent button cables call bell calling wire carbon cause central office centre circuit circuit breaker communication connected consists constructed cord core corresponding cylinder described diaphragm disk distance Dolbear Drawbaugh duced Edison effect electric current electro magnet employed experiments fastened front galvanometer heard hole human voice induction coil inserted instru insulated invention inventor jack knife switch lamp black latter lever loudness means membrane ment metallic microphone motion mouth piece musical tones operator passing permanent magnet phonautograph photophone pitch placed plate plug poles pressure produced Prof receiving instrument reed Reis represents reproduce resistance screw selenium shown in fig signals soft iron sound speaking telephone spring jack strip subscriber's subscribers switch board tele tion transmission transmitter tube tuning fork undulatory current varying vertical vibrations vocal wire
Page 448 - The method of, and apparatus for, transmitting vocal or other sounds telegraphically, as herein described, by causing electrical undulations, similar in form to the vibrations of the air accompanying the said vocal or other sounds, substantially as set forth.
Page 514 - It has long been known that when a permanent magnet is caused to approach the pole of an electro-magnet, a current of electricity is induced in the coils of the latter, and that, when it is made to recede, a current of opposite polarity to the first appears upon the wire.
Page 517 - These undulations are similar in form to the air vibrations caused by the sound — that is, they are represented graphically by similar curves. The undulatory current passing through the electro-magnet f influences its armature h to copy the motion of the armature c. A similar sound to that uttered into A is then heard to proceed from L. In this specification the three words "oscillation," "vibration," and "undulation-," are used synonymously, and in contradistinction to the terms "intermittent
Page 458 - I do not, however, claim even the credit of inventing it, as I do not believe a mere description of an idea that has never been reduced to practice — in the strict sense of that phrase — should be dignified with the name invention.
Page 52 - ... click of the instruments, and in this way were enabled to distinguish by ear the various signals. It struck me that in a similar manner the duration of a musical note might be made to represent the dot or dash of the telegraph code, so that a person might operate one of the keys of the...
Page 510 - But Bell discovered a new art — that of transmitting speech by electricity — and has a right to hold the broadest claim for it which can be permitted in any case; not to the abstract right of sending sounds by telegraph, without any regard to means, but to all means and processes which he has both invented and claimed. The invention is nothing less than the transfer to a wire of electrical vibrations like those which a sound has produced in the air.
Page 515 - ... apart. The reciprocal vibration of the elements of a battery, therefore, occasions an undulatory action in the voltaic current. The external resistance may also be varied. For instance, let mercury or some other liquid form part of a voltaic circuit...
Page 93 - With somewhat more advanced plans and more powerful apparatus, we may confidently expect that Mr. Bell will give us the means of making voice and spoken words audible through the electric wire to an ear hundreds of miles distant.
Page 74 - ... and thickness of the steel spring, the size and power of the magnet, and the coils of insulated wire around their poles, to discover empirically the exact effect of each element of the combination, and thus to deduce a more perfect form of apparatus. It was found that a marked increase in Pig.
Page 68 - Boston was freely placed at my disposal for these experiments, and it happened that at that time a student of the Institute of Technology, Mr. Maurey, had invented an improvement upon the phonautograph. He had succeeded in vibrating by the voice a stylus of wood about a foot in length which was attached to the membrane of the phonautograph, and in this way he had been enabled to obtain enlarged tracings upon a plane sufacc of smoked glass.