The Reproducing Mirror.

New Zealand Mail, 22 April 1887, Page 9

The Reproducing Mirror.

In this age of miracles in science, surprise at a new discovery, however brilliant, is almost impossible, and it is doubtful if the announcement that heliographic communication had been established with the inhabitants of Mars would excite more than passing wonder. Still, more than ordinary interest mutt

f necessarily be aroused by the report from Parnr, recently published in the Times that, after five years’ patient experiment, Dr. Baonl Duvernay and M. Pictet have succeeded iu making a mirror v.be.-e images can at aoy time be reproduced at tvi.f. Ti e Secret of the process has net be-n divulged, but the claim is that all images o. e r fi -cti-d by the mirror are r; talced, may be rue c-.rive!y made to rer, and may even then he photographed and made permanent. Tie sensitive medium employed is said to he selenium, tho n.tUlniid whoee violent molecular changes uixLr the ii (Lienee of light have already made the pbotoleiepboco possible—musL.al tones and even speech being reproduced at a distance o? two miles by employing a selenium di-k, upon which is piojscted a ray of light from the transmitting station, vibrating in unison with tho diaphragm acuafed by the speaker. The experiments in radiophony by Tyndall and Mercadier, the spectrrphone of Tainter, and the slii! older and better known chart of Fraunheferis lines, have shown that all substances are molecularly affected by light, but none of these discoveries has prepared the world for the astonishing miracle of the reproducing mirror, if it truly be as alleged. It is easy to conceive of a selenium mirror exposed for one instant behind a lens, and then covered, retaining the image of surrounding objects, much as the sensitive film in a camera would retain it, and equally easy to believe that the image so retained could be visibly reproduced under certain conditions. But to contemplate the exposure of the mirror in an ordinary manner to a constant succession of images for a long period of time, and then successively to reproduce these in inverse order, as it is claimed by Pictet and Duvernay may be accomplished by their invention, is not within the rauge of credibility, unless these gentlemen have succeeded in forcing light to a violent departure from its customary laws. In the first place, selenium is not more sen v.tiva than the iodic salts of silver u->ed in the photograph. An image cast upon these may be rtproduced, but only one image on each plate. 1 wo or more images result in a hopele-a confusion of tbe blurred lines. Again, the sensitive photograph plate, exposed as a m'rror would be e-posed, receives no impression at all. Rays irom each point of the object strike all points of the plate. To compel all rays from each poiat to impinge upon a given point of bhe plate necessitates the use of a lens. The same would apply to a mirror. The eye perceives an image in a mirror only by reason of the law of reflection compelling one given ray from the object reflected vo strike the eye at a given angle.- Rays from other points corns at diff rent angles, and the result is practically that achieved by tho camera. For P.ctet aud Daveroay to expose their mirror in a camera is but to duplicate the discovery of Daguerre. It they expose it wi hout the camera the result will be the same as in the case of a dry photograph plate so exposed. Mr Keely claims to have discovered a new force and new properties of matter, and to have successfully enslaved them to his will. Men knowing the rudimentary and uunlterable laws of nature need not investigate the ‘ vibrator,* ‘ resonator,’ and ‘ etheric icrces to s t'tfy themselves that Mr Keely is a charlatan and . his motor a humbug. The laws of light are known, and although its dynamics are not clearly understood, there is nothing to prove that tbe alleged producing mirror, as specified in Pictet and Duvernay’s claims is a scientific possibility, and a thousand fac*3 to prove that it is an unscientific fraud. —N.Y. Time?.