TELEPHONES AND MICROPHONES AT THE ELECTRICAL EXHIBITION.

Lyttelton Times, Volume LVI, Issue 6503, 30 December 1881, Page 5

TELEPHONES AND MICROPHONES AT THE ELECTRICAL EXHIBITION.

The Timet correspondent, in describing the working of the above instruments at the Exhibition say*:—ln 1876 I remember hearing Sir William Thomson, who had just returned from the Philadelphia Exhibition, declare that he hod distinctly heard tbe sentence, "To be or not to be, that is the question," transmitted through a considerable distance of wire with the aid of an instrument celled a telephone, the invention of Mr Graham Bell. The statement was received by many almost with incredulity, while others were surprised to learn that what they had looked upon ae an American exaggeration was an actual feet. The importance of the invention was so patent that it is safe to say that hundreds of inventors occupied themselves in trying to improve the instrument. Yet at the present day the best forms of telephones have been but little changed Dorn their old construction. Each one hoe tried to make the sounds loader and mote distinct, and some success has attended these efforts. Mr Bell’s instrument consisted simply of a straight magnet, with an iron diaphragm in front of one of tbe poles, and insulated wire coiled round that pole. The transmitter and receiver were identical, and were connected together by the line-wire. Speech consists of vibrations transmitted through the air, the intensity and sequence of the vibrations determining the nature of the sound. The air seta the diaphragm Into corresponding vibrations; the moyemect of the diaphragm sends electric currents through the coil of wire, end thus through the me to the distant telephone. Tbe intensity- and sequence of these electric currents correspond exactly to those of the sound vibrations. At the receiving end the currents increase or diminish tbe magnetism of the telephone, and so attract the diaphragm and cause it to vibrate. These vibrations ore exactly proportional in intensity to, and follow the sequence of, the original sound vibrations, and so tbe words spoken into the telephone at one end of the une can be heard by an ear placed at the telephone at the other end of the line. A similar telephone to Mr Bell’s was patented the same day aa his by Mr Elisha Gray. Since then the most important improvement in the instrument consists in the use of both the pcles of a magnet to act upon the diaphragm. This is the form need by Gower and others.

These instruments, however, allow only a single person to hear the sounds transmitted. They also require that the mouth of the speaker should be dose to his instrument. Vast improvements have been made since Mr Hughes invented the microphone. This gentleman found that when a current is passing through a circuit, pert of which consists of a hose contact between pieces of carbon, which may rest on a piece of wood; then, if a telephone be in the circuit, the slightest vibrations which may bo communicated to the wood— e.ff., by the sound of the voice, or by the footsteps of a fly even—are heard in tire telephone. The invention was given to the public, and many different sorts or microphones have been constructed. The forms which are in moet general use at present allow a number of different paths to the electric current through loose junctions of carbon, all supported on the wood which receives the vibration. One resembles a cart-wheel in which the rim, spokes, and hob are all separate pieces of carbon, the currant peering through the hub and through the spokes to tits rim. In another the arrangement is of a gridiron form. These instruments are now generally used in telephone exchanges. The mouth of the speaker does not require to he dose to the instrument. The different systems of telephones and microphones are shown in different sections; alto the arrangements which a» required in a telephone exchange; and the viator can make actual testa of their action in the exhibition by convening with people in different parts of Baris. I must now describe the very interesting application of these instrument), to which 1 have alluded in the commencement of this letter. It is none other than giving to numbers of people in the Exhibition the plea*are of listening night after night to the splendid oomnaniee at the opera ami at the Xhfi&tre Pranqai*. Booms have been fitted up in the galleries, each with a number of pair* of telephones. Two rooms at* devoted to the Op&a and two to the Tfa&tro. The former is the more interesting, for there the actions and features of the performers are el leas importance. Ton enter the room in group* of, perhaps, ten at a time. Each one advances to a wall and seises a pair of telephones, which he places to hit two cars. Each of these is connected with a microphone on the stage of the Opfira, one to the right, the other to the left of the prompter and inclined towards the sincere. The microphone to the right of the prompter is connected with the telephone at our right ear, the one to Ms left is connected with that at our left ear. Thus, while the singer moves to right or left, lbs sounds inorssse or diminish in the right or left ear } when they advance or weed* the sounds increase or diminish in both, and thus we are able to appreciate their movement*, audit becomes aitficult to believe that the performances on the stage are not directly behind the wall which we aw ferine. 80 soon as the telephones are applied to the ear* the glorious voices of the finest ringers m Pans are heard by us undiminished in purity, beauty, or force by the strange msans which have carried them to us over a distance of a mile. The orchestral accompaniment Ik somewhat weak, owing to the arrangement of the mierophonse. We can almost see the ringer move about, putting expression into the meutio by inoitmost tod lotion i iu oo part of the opera-home can you hear with greater (I might almost say with so great) clearness and power as in this tapestried room in the PMois d'lndustrie. It ie somewhat curious to watch the different listeners, if we have not a telephone in h«nd ourselves. Perfect silence reigns 1 ten people stud round, with their hands holding to their head* things which look like large ears. You can see an expression of satisfaction, of sadness, of rapture on their faro* 1 they look st each other and express approval with their eyesj and when the end of the solo haa been reached, and they hear the clapping of hands and bravos of the audience, they lay down their telephones and frequently join their applause unheard to that of the audience at the Oplra, unable to restrain themselves from the expression of them dolight. . , There are a few defects, but these are of a minor importance. The orchestra is a little too much subdued 1 a crackling noise is sometimes heard (but very rarely), wMoh comes from the microphone 1 and there are special notes which seem to bo reinforced by the instruments and to be heard with undue loudness. These defects are* however, baldly noticeable, and, as a tide, the deepest bass and the highest soprano can be listened to and heard through all their most delicate changes a* accurately and almost with as greet pleasure as at the Opera itself. Having now described the perfomanoe at the Opera in some detoil, I need only say that likewise the Francis u extremely interesting to listen to. Every word can be

distinctly beard, and the double arrangement of microphone* allow* us, to a great extent, to hear, if not to tee, the movement* of the actors.