THE TELEPHONE.
So much have times altered in the last fifty years, that the electric telegraph itself, which now reaches its thin arms into more than six thousand offices, is threatened in its turn with serious rivalry at the hands of a youthful but vigorous competitor, the telephone. Its advantages are such that its ultimate popularity cannot be a matter of doubt. It is no small benefit to be able to recognise voices, to transact business with promptitude by word of mouth, to get a reply, 'Yes' or 'No,' on the spot, instead of having to rush to the nearest telegraph office.
Great inventions are often conceived a long time before they are realised in practice. Sometimes the original idea occurs to the man who subsequently works it out; and sometimes it comes as a happy thought to one who is either in advance of his age, or who is prevented by adverse circumstances from following it up, and who yet lives to see the day when some more fortunate individual gives it a material shape, and so achieves the fame which was denied to him. Such is the case of M. Charles Bourselle, who in 1854 proposed a form of speaking-telephone, which, although not practicable in its first crude condition, might have led its originator to a more successful instrument if he had pursued the subject further.
The telephone is an instrument designed to reproduce sounds at a distance by means of electricity. It was believed by most people, and even by eminent electricians, that the speaking-telephone had never been dreamed of by any one before Professor Graham Bell introduced his marvellous little apparatus to the scientific world. But that was a mistake. More than one person had thought of such a thing, Bourselle among the number. Philip Reis, a German electrician, had even constructed an electric telephone in 1864, which transmitted words with some degree of perfection; and the assistant of Reis asserts that it was designed to carry music as well as words. Professor Bell, in devising his telephone, copied the human ear with its vibrating drum. The first iron plate he used as a vibrator was a little piece of clock-spring glued to a parchment diaphragm, and on saying to the spring on the telephone at one end of the line: 'Do you understand what I say?' the answer from his assistant at the other end came back immediately: 'Yes; I understand you perfectly.' The sounds were feeble, and he had to hold his ear close to the little piece of iron on the parchment, but they were distinct; and though Reis had transmitted certain single words some ten years before, Bell was the first to make a piece of matter utter sentences. Reis gave the electric wire a tongue so that it could mumble like an infant; but Bell taught it to speak.
The next step is attributed to Mr Elisha Gray of Chicago, who sent successions of electrical current of varying strength as well as of varying frequency into the circuit, and thus enabled the relative loudness as well as the pitch of sounds to be transmitted; and who afterwards took the important step of using the variations of a steady current. These variations, positive and negative, are capable of representing all the back-and-fore variations of position of a particle of air, however irregular these may be: and he secured them by making the sound-waves set a diaphragm in vibration. This diaphragm carried a metallic point which dipped in dilute sulphuric acid; the deeper it dipped the less was the resistance to a current passing through the acid, and vice versâ: so that every variation in the position of the diaphragm produced a corresponding variation in the intensity of the current: and the varying current acted upon a distant electro-magnet, which accordingly fluctuated in strength, and in its attraction for a piece of soft iron suspended on a flexible diaphragm: this piece of soft iron accordingly oscillated, pulling the flexible diaphragm with it; and the variations of pressure in the air acted upon by the diaphragm produced waves, reproducing the characteristics of the original sound-waves, and perceived by the ear as reproducing the original sound or voice. Mr Gray lodged a caveat for this contrivance in the United States Patent Office on 14th February 1876; but on the same day Professor Alexander Graham Bell filed a specification and drawings of the original Bell telephone.
Bell's telephone was first exhibited in America at the Centennial Exhibition in Philadelphia in 1876; and in England, at the Glasgow meeting of the British Association in September of that year. On that occasion, Sir William Thomson (now Lord Kelvin) pronounced it, with enthusiasm, to be the 'greatest of all the marvels of the electric telegraph.' The surprise created by its first appearance was, however, nothing to the astonishment and delight which it aroused in this country when Professor Bell, the following year, himself exhibited it in London to the Society of Telegraph Engineers. Since then, its introduction as a valuable aid to social life has been very rapid, and the telephone is now to be found in use from China to Peru.