THE MICROPHONE.

Globe, Volume XX, Issue 1402, 13 August 1878, Page 2

THE MICROPHONE.

Some very interesting preliminary experiments with the newly-discovered adjunct to electrical science, the microphone, were conducted last evening by Mr W. G. Meddings. As will be recollected a description of the instrument appeared a short time hack, together with an account of some very startling experiments which had been performed by scientific men at home. By means of the microphone the walk of a fly crossing the sound board was magnified into a sound resembling the tramp of a horse, and other results were obtained equally startling. The exper meets of last evening, though proving incontestably the powers of the instrument, were only preliminary, the proper adjustment of it having yet to be ascertained, besides which the room in which the experiment was tried was found to be unsuitable The organisation of the microphone, as might be imagined, is exceedingly delicate, and affected by the least sound, and the room used being very large, and almost empty of furniture, was somewhat too resonant to obtain the full effect. In order to secure the quiet so necessary for the perfect success of the experiment, Mr Meddings had laid a wire on to the office opposite the telegraph office, and connected the microphone therewith. The apparatus is of the simplest kind to look at, and it is difficult at first sight to account for the extraordinary power of magnifying sound which it possesses. Those tried last night were of three kinds, two being constructed on the principle of those used in England, and the other after an idea of Mr Meddings’. The first of these consists of a wooden box, open at one end, npon which, supported by brass standards, is a horizontal bar of carbon, resting npon a square bio k of the same material, having at the sides an attachment for the wire. The second is a similar bar, only placed horizontally. Mr Meddings’ idea differs considerably from that of the English model, and the results last evening, so far as they went, showed that this was the be*t for magnifying purposes. On a box similar to the one already described, is a bar of carbon, supported by brass standards, but having a steel pinion upon which it works. At the extreme end of the bar is a wedge-shaped piece of carbon screwed on each side with two small nuts ; this wedge is flat on the top and rounded at the sides, and rests on a square block of carbon. The poise of the bar is regulated by a screw at the further end, which allows the wedge to play with greater or less freedom on the square block of carbon. The wires being attached and carried to the telephones, communication was opened with Akaroa. For some little time, owing to the bad acoustic properties of the room, the results obtained were not so satisfactory as those previously obtained by Mr Meddings in his telegraph room. Mr Meddings then stood away from the microphone some yards and spoke in an ordinary tone of voice, not through the telephone, but simply into the room, and was heard with some amount of distinctness by the operator at the Akaroa end. A gentleman whoso capabilities as a whistler has already earned for him the attention of some Government officials, volunteered a taste of his quality, and whistled an Italian air, which waa spoken of by the Akaroa audience as being very good. The next experiment was a very interesting one. A watch was laid upon the top of the box upon which the carbon lever was placed, technically called the sound board, and the tickings were immediately magnified to as great an extent as an ordinary eight day clock, and wore also heard t > some extent at Akaroa. Subsequently the Akaroa circuit was cut off, and some experiments conducted between the Telegraph office and the room in which the experiments were first commenced. Here the results obtained were exceedingly intere ting. For instance, the rubbing of the edge of a sheet of paper on the box at one end of the circuit was magnified into the loudest description of cross cut saw’ing, so as to be positively painful to the ear, whilst a gentle tap on the table became like the blow of a hammer. The same results were obtained by touching the table on which the microphone stood. Generally, although from the reasons stated, the experiments were net *o successful as was anticipated, yet they were so much so as to show conclusively that by the discovery of the microphone yet another step has been made in the development of electrical science. Mr Meddings intends making another trial shortly, when we hope to e able to record perfect success.