heroes of the telegraph-第40节
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； And the regret they leave remains alone。' Again； in his SPIRIT OF SOLITUDE； we find： 'The fire of those soft orbs has ceased to burn； And silence too enamoured of that voice Locks its mute music in her rugged cell；'＇
The phonograph lay under the very eyes of Science； and yet she did not see it。 The logograph had traced all the curves of speech with ink on paper； and it only remained to impress them on a solid surface in such a manner as to regulate the vibrations of an artificial tympanum or drum。 Yet no professor of acoustics thought of this； and it was left to Edison； a telegraphic inventor； to show them what was lying at their feet。
Mere knowledge； uncombined in the imagination； does not bear fruit in new inventions。 It is from the union of different facts that a new idea springs。 A scholar is apt to be content with the acquisition of knowledge； which remains passive in his mind。 An inventor seizes upon fresh facts； and combines them with the old； which thereby become nascent。 Through accident or premeditation he is able by uniting scattered thoughts to add a novel instrument to a domain of science with which he has little acquaintance。 Nay； the lessons of experience and the scruples of intimate knowledge sometimes deter a master from attempting what the tyro； with the audacity of genius and the hardihood of ignorance； achieves。 Theorists have been known to pronounce against a promising invention which has afterwards been carried to success； and it is not improbable that if Edison had been an authority in acoustics he would never have invented the phonograph。 It happened in this wise。 During the spring of 1877； he was trying a device for making a telegraph message； received on one line； automatically repeat itself along another line。 This he did by embossing the Morse signals on the travelling paper instead of merely inking them； and then causing the paper to pass under the point of a stylus； which； by rising and falling in the indentations； opened and closed a sending key included in the circuit of the second line。 In this way the received message transmitted itself further； without the aid of a telegraphist。 Edison was running the cylinder which carried the embossed paper at a high speed one day； partly； as we are told； for amusement； and partly to test the rate at which a clerk could read a message。 As the speed was raised； the paper gave out a humming rhythmic sound in passing under the stylus。 The separate signals of the message could no longer be distinguished by the ear； and the instrument seemed to be speaking in a language of its own； resembling 'human talk heard indistinctly。' Immediately it flashed on the inventor that if he could emboss the waves of speech upon the paper the words would be returned to him。 To conceive was to execute； and it was but the work of an hour to provide a vibrating diaphragm or tympanum fitted with an indenting stylus； and adapt it to the apparatus。 Paraffined paper was selected to receive the indentations； and substituted for the Morse paper on the cylinder of the machine。 On speaking to the tympanum； as the cylinder was revolved； a record of the vibrations was indented on the paper； and by re…passing this under the indenting point an imperfect reproduction of the sounds was heard。 Edison 'saw at once that the problem of registering human speech； so that it could be repeated by mechanical means as often as might he desired； was solved。' ＇T。 A。 Edison； NORTH AMERICAN REVIEW； June； 1888； New York ELECTRICAL REVIEW； 1888；＇
The experiment shows that it was partly by accident； and not by reasoning on theoretical knowledge； that the phonograph was discovered。 The sound resembling 'human talk heard indistinctly' seems to have suggested it to his mind。 This was the germ which fell upon the soil prepared for it。 Edison's thoughts had been dwelling on the telephone； he knew that a metal tympanum was capable of vibrating with all the delicacies of speech； and it occurred to him that if these vibrations could be impressed on a yielding material； as the Morse signals were embossed upon the paper； the indentations would reproduce the speech； just as the furrows of the paper reproduced the Morse signals。 The tympanum vibrating in the curves of speech was instantly united in his imagination with the embossing stylus and the long and short indentations on the Morse paper； the idea of the phonograph flashed upon him。 Many a one versed in acoustics would probably have been restrained by the practical difficulty of impressing the vibrations on a yielding material； and making them react upon the reproducing tympanum。 But Edison； with that daring mastery over matter which is a characteristic of his mechanical genius； put it confidently to the test。
Soon after this experiment； a phonograph was constructed； in which a sheet of tinfoil was wrapped round a revolving barrel having a spiral groove cut in its surface to allow the point of the indenting stylus to sink into the yielding foil as it was thrust up and down by the vibrating tympanum。 This apparatus the first phonographwas published to the world in 1878； and created a universal sensation。 ＇SCIENTIFIC AMERICAN； March 30； 1878＇ It is now in the South Kensington Museum； to which it was presented by the inventor。
The phonograph was first publicly exhibited in England at a meeting of the Society of Telegraph Engineers； where its performances filled the audience with astonishment and delight。 A greeting from Edison to his electrical brethren across the Atlantic had been impressed on the tinfoil； and was spoken by the machine。 Needless to say； the voice of the inventor； however imperfectly reproduced； was hailed with great enthusiasm； which those who witnessed will long remember。 In this machine； the barrel was fitted with a crank； and rotated by handle。 A heavy flywheel was attached to give it uniformity of motion。 A sheet of tinfoil formed the record； and the delivery could he heard by a roomful of people。 But articulation was sacrificed at the expense of loudness。 It was as though a parrot or a punchinello spoke； and sentences which were unexpected could not be understood。 Clearly； if the phonograph were to become a practical instrument； it required to be much improved。 Nevertheless this apparatus sufficiently demonstrated the feasibility of storing up and reproducing speech； music； and other sounds。 Numbers of them were made； and exhibited to admiring audiences； by license； and never failed to elicit both amusement and applause。 To show how striking were its effects； and how surprising； even to scientific men； it may be mentioned that a certain learned SAVANT； on hearing it at a SEANCE of the Academie des Sciences； Paris； protested that it was a fraud； a piece of trickery or ventriloquism； and would not be convinced。
After 1878 Edison became too much engaged with the development of the electric light to give much attention to the phonograph； which； however； was not entirely overlooked。 His laboratory at Menlo Park； New Jersey； where the original experiments were made； was turned into a factory for making electric light machinery； and Edison removed to New York until his new laboratory at Orange； New Jersey； was completed。 Of late he has occupied the latter premises； and improved the phonograph so far that it is now a serviceable instrument。 In one of his 1878 patents； the use of wax to take the records in place of tinfoil is indicated； and it is chiefly to the adoption of this material that the success of the 'perfected phonograph' is due。 Wax is also employed in the 'graphophone' of Mr。 Tainter and Professor Bell； which is merely a phonograph under another name。 Numerous experiments have been made by Edison to find the bees…wax which is best adapted to receive the record； and he has recently discovered a new material or mixture which is stated to yield better results than white wax。
The wax is moulded into the form of a tube or hollow cylinder； usually 4 1/4 inches long by 2 inches in diameter； and 1/8 inch thick。 Such a size is capable of taking a thousand words on its surface along a delicate spiral trace； and by paring off one record after another can be used fifteen times。 There are a hundred or more lines of the trace in the width of an inch； and they are hardly visible to the naked eye。 Only with a magnifying glass can the undulations caused by the vibrating stylus be distinguished。 This tube of wax is filed upon a metal barrel like a sleeve； and the barrel； which forms part of a horizontal spindle； is rotated by means of a silent electro…motor； controlled by a very sensitive governor。 A motion of translation is also given to the barrel as it revolves； so that the marking stylus held over it describes a spiral path upon its surface。 In front of the wax two small metal tympanums are supported； each carrying a fine needle point or stylus on its under centre。 One of these is the recording diaphragm； which prints the sounds in the first place； the other is the reproducing diaphragm； which emits the sounds recorded on the wax。 They are used； one at a time； as the machine is required； to take down or to render back a phonographic message。
The recording tympanum； which is about the size of a crown
