heroes of the telegraph-第39节
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； thereby varying the electric current and deflecting the needle of the galvanometer to one side or the other。 The instrument was said to indicate a change of temperature equivalent to one…millionth of a degree Fahrenheit。 It was tested by Edison on the sun's corona during the eclipse observations of July 29； 1875； at Rawlings； in the territory of Wyoming。 The trial was not satisfactory； however； for the apparatus was mounted on a hen…house； which trembled to the gale； and before he could get it properly adjusted the eclipse was over。
It is reported that on another trial the light from the star Arcturus； when focussed on the vulcanite； was capable of deflecting the needle of the galvanometer。 When gelatine is substituted for vulcanite； the humidity of the atmosphere can also be measured in the same way。
Edison's crowning discovery at Menlo Park was the celebrated 'phonograph；' or talking machine。 It was first announced by one of his assistants in the pages of the SCIENTIFIC AMERICAN for 1878。 The startling news created a general feeling of astonishment； mingled with incredulity or faith。 People had indeed heard of the talking heads of antiquity； and seen the articulating machines of De Kempelen and Faber； with their artificial vocal organs and complicated levers； manipulated by an operator。 But the phonograph was automatic； and returned the words which had been spoken into it by a purely mechanical mimicry。 It captured and imprisoned the sounds as the photograph retained the images of light。 The colours of Nature were lost in the photograph； but the phonograph was said to preserve the qualities even of the human voice。 Yet this wonderful appliance had neither tongue nor teeth； larynx nor pharynx。 It appeared as simple as a coffee…mill。 A vibrating diaphragm to collect the sounds； and a stylus to impress them on a sheet of tinfoil； were its essential parts。 Looking on the record of the sound； one could see only the scoring of the stylus on the yielding surface of the metal； like the track of an Alpine traveller across the virgin snow。 These puzzling scratches were the foot…prints of the voice。
Speech is the most perfect utterance of man； but its powers are limited both in time and space。 The sounds of the voice are fleeting； and do not carry far； hence the invention of letters to record them； and of signals to extend their range。 These twin lines of invention； continued through the ages； have in our own day reached their consummation。 The smoke of the savage； the semaphore； and the telegraph have ended in the telephone； by which the actual voice can speak to a distance； and now at length the clay tablet of the Assyrian； the wax of the ancient Greek； the papyrus of the Egyptian； and the modern printing…press have culminated in the phonograph； by which the living words can be preserved into the future。 In the light of a new discovery； we are apt to wonder why our fathers were so blind as not to see it。 When a new invention has been made； we ask ourselves； Why was it not thought of before？ The discovery seems obvious； and the invention simple； after we know them。 Now that speech itself can be sent a thousand miles away； or heard a thousand years after； we discern in these achievements two goals toward which we have been making； and at which we should arrive some day。 We marvel that we had no prescience of these； and that we did not attain to them sooner。 Why has it taken so many generations to reach a foregone conclusion？ Alas！ they neither knew the conclusion nor the means of attaining to it。 Man works from ignorance towards greater knowledge with very limited powers。 His little circle of light is surrounded by a wall of darkness； which he strives to penetrate and lighten； now groping blindly on its verge； now advancing his taper light and peering forward； yet unable to go far； and even afraid to venture； in case he should be lost。
To the Infinite Intelligence which knows all that is hidden in that darkness； and all that man will discover therein； how poor a thing is the telephone or phonograph； how insignificant are all his 'great discoveries'！ This thought should imbue a man of science with humility rather than with pride。 Seen from another standpoint than his own； from without the circle of his labours； not from within； in looking back； not forward； even his most remarkable discovery is but the testimony of his own littleness。 The veil of darkness only serves to keep these little powers at work。 Men have sometimes a foreshadowing of what will come to pass without distinctly seeing it。 In mechanical affairs； the notion of a telegraph is very old； and probably immemorial。 Centuries ago the poet and philosopher entertained the idea of two persons far apart being able to correspond through the sympathetic property of the lodestone。 The string or lovers' telephone was known to the Chinese； and even the electric telephone was thought about some years before it was invented。 Bourseul； Reis； and others preceded Graham Bell。
The phonograph was more of a surprise； but still it was no exception to the rule。 Naturally； men and women had desired to preserve the accents as well as the lineaments of some beloved friend who had passed away。 The Chinese have a legend of a mother whose voice was so beautiful that her children tried to store it in a bamboo cane； which was carefully sealed up。 Long after she was dead the cane was opened； and her voice came out in all its sweetness； but was never heard again。 A similar idea （which reminds us of Munchausen's trumpet） is found in the NATURAL MAGICK of John Baptista Porta； the celebrated Neapolitan philosopher； and published at London in 1658。 He proposes to confine the sound of the voice in leaden pipes； such as are used for speaking through； and he goes on to say that 'if any man； as the words are spoken； shall stop the end of the pipe； and he that is at the other end shall do the like； the voice may be intercepted in the middle； and be shut up as in a prison； and when the mouth is opened； the voice will come forth as out of his mouth that spake it。 。 。 。 I am now upon trial of it。 If before my book be printed the business take effect； I will set it down； if not； if God please； I shall write of it elsewhere。' Porta also refers to the speaking head of Albertus Magnus； whom； however； he discredits。 He likewise mentions a colossal trumpeter of brass； stated to have been erected in some ancient cities； and describes a plan for making a kind of megaphone； 'wherewith we may hear many miles。'
In the VOYAGE A LA LUNE of De Cyrano Bergerac； published at Paris in 1650； and subsequently translated into English； there is a long account of a 'mechanical book' which spoke its contents to the listener。 'It was a book； indeed；' says Cyrano； 'but a strange and wonderful book； which had neither leaves nor letters；' and which instructed the Youth in their walks； so that they knew more than the Greybeards of Cyrano's country； and need never lack the company of all the great men living or dead to entertain them with living voices。 Sir David Brewster surmised that a talking machine mould be invented before the end of the century。 Mary Somerville； in her CONNECTION OF THE PHYSICAL SCIENCES； wrote some fifty years ago： 'It may be presumed that ultimately the utterances or pronunciation of modern languages will be conveyed； not only to the eye； but also to the ear of posterity。 Had the ancients possessed the means of transmitting such definite sounds； the civilised world must have responded in sympathetic notes at the distance of many ages。' In the MEMOIRES DU GEANT of M。 Nadar； published in 1864； the author says： 'These last fifteen years I have amused myself in thinking there is nothing to prevent a man one of these days from finding a way to give us a daguerreotype of soundthe phonograph something like a box in which melodies will be fixed and kept； as images are fixed in the dark chamber。' It is also on record that； before Edison had published his discovery to the world； M。 Charles Cros deposited a sealed packet at the Academie des Sciences； Paris； giving an account of an invention similar to the phonograph。
Ignorance of the true nature of sound had prevented the introduction of such an instrument。 But modern science； and in particular the invention of the telephone with its vibrating plate； had paved the way for it。 The time was ripe； and Edison was the first to do it。
In spite of the unbridled fancies of the poets and the hints of ingenious writers； the announcement that a means of hoarding speech had been devised burst like a thunderclap upon the world。
＇In seeing his mother's picture Byron wished that he might hear her voice。 Tennyson exclaims； 'Oh for the touch of a vanished hand； and the sound of a voice that is still！' Shelley； in the WITCH OF ATLAS； wrote： 'The deep recesses of her odorous dwelling Were stored with magic treasuressounds of air； Which had the power all spirits of compelling； Folded in cells of crystal silence there； Such as we hear in youth； and think the feeling Will never dieyet ere we are aware； The feeling and the sound are fled and gone； And the regret they leave remains alone。' Again； in his SPIRIT OF SOLITUDE； we find： 'The fire of
