PHOTOGRAPHING MUSICAL TONES.

Globe, Volume VIII, Issue 915, 31 May 1877, Page 3

PHOTOGRAPHING MUSICAL TONES.

We find the following in a London paper of recent date i—" One of the latest novelties in applied science, it seems, is to photograph musical tones, and in this way to record by light sounds that are usually apparent only to the ear. The art of photography has already worked so many wonders that few probably will be astonished at any further feats it may be able to accomplish. At Greenwich for a long time past the magnetic pulsations of the earth have been automatically written down by that most faithful and trustworthy of cicrks, and at the Kcw Observatory we hear of daily records being secured by the sun, whenever that of late rather bashful luminary can be prevailed upon to show its face. The movements of the barometer and thermometer are also noted nowadays by the retina of a sensitive plate, and doctors may employ the same infallible and sharp-eyed tell-tale to register the pulse beats of their patients. It is, perhaps, only in the natural course of events, therefore, that notes and sounds [should be found capable of being written down by the same wonderful agency. Dr. Tyndall showed us some years ago how flames were influenced by sounds uttered in their immediate neighbourhood, and how they were capable of appreciating various intonations in a very marked degree ; indeed, if we remember rightly, one flame that he exhibited was so sensitive that, like a delicate-minded person, it invariably went out when some particular word or vowel was mentioned. M. Koenig, of Paris, has already essayed to record by photography the change that overcomes flames from this cause, but a German physicist, Dr Stein, lias successfully accomplished the ' photography of tones ' by a much more direct method. His plan, it appears, is simply to fix upon a violin string an upright disk or screen of mica, with a hole in it. A brilliant ray of light is made to pass through this little hole on to a sensitive photographic plate, which moves along at a rapid pace. Of course, if the disk and the tiny orifice in it remain perfectly stationary while the photographic plate is moving, all that will be produced in the end upon the plate is a long and even line, where the ray of light has acted. But as soon as the string vibrates —as soon, that is, as the violin bow is drawn across it— the little disk also trembles and vibrates, moving up and down with great celerity, and the ray of light reflected upon the photographic plate behaving in a similar manner, a curved line is the result, and the number of these curves denotes the number of vibrations, which are thus made visible and so easily counted. All ordinary musical tones, it is said, can be photographed in this way, and Dr Stein has been able to register several notes together by fixing the disks attached to a series of strings like those of a violin, one above another, so that four curved lines are written down at once."