NOCTOVISION.

Press, Volume LXIII, Issue 19140, 25 October 1927, Page 8

NOCTOVISION.

princess mary and a ■ .■,.'■..:.'. ■.tesl , .v...v.;: : ;:;:'v:, MR J. L. BAiRD'S E&PERrMENTS. (moil OUB o'w* COBBXSrOHD.EST.) LONDON, September 1., Apart from the somewhat bewildering embarrassment in the. dose-on-400-papers : which are to .be' read at tho British Association meeting,. at Leeds., .this year's assembly promises, to be marked by other intensely interesting features.

Take, for instance, the television and noctovision experiments which are to be carried out by Mr J. L. Baird. It is understood by the Leeds correspondent of the "Daily Telegraph" that possibly Princess Mary Viscountess Lascelles will' participate in one. of the experiments. •- Her Royal; Highness .< is expected to', visit; the exhibition.-' or scientific, instruments -connected with the 'Association meeting, . and it is hoped that she and Viscount Lascelles will take part in a demonstration oi* noctovision—that is, ..television, using infra rod rays instead of ordinary light for illumination—to be given l in the Education Department buildings. The Princess will be seated in a dark room, and, by means of Mr Baird's perfected wonderworking noctovision apparatus, her features will be revealed on a screen in an adjoining room to Viscount Lascelles. It is hoped further to transmit the Princess's picture from the same Leeds room to the headquarters of the Baird Television. Company in London.. A series of: television and noctovision, demonstrations between London and Leeds will be made another day, members ■of the British Association . taking part in, them at this end. For the transmission of faces from the metropolis, .wireless may be utilised, otherwise • trunk telephone wires, while from Leeds to London reliance will be on trunk telephone, wires. It may be recalled that by using"* in place of light, infra red rays in conjunction with a modified form-of television receiver and transmitter,' Mr Baird was able at the end of last year to demonstrate vision in total darkness to members of the Royal Institiir tion. On that occasion persons, seated in a totally dark room .were, seen and recognised by friends on a screen in a different apartment, all movements being faithfully portrayed Apart from demonstrations of television, which may be briefly defined as transmission of vision by electricity, and demonstrations of noctovisionvision produced in darkness by »ncans of infra red rays—there are to be.revealed the uncanny powers 'of ■'lb/! phonovisor, an apparatus by which moving images can. be recorded on and reproduced from, a photograph record in the same manner as sound. In the transmission of an. object or swno by television, the image" or scene' is" * first transformed into a fluctuating electric current. This-current may be heard in the telephone as a sound; everv face or scene having its corresconding sound. The .lights'-and shades" of different faces cause different' sounds, ami it, is even possible to' distinguish one faco from another by these differ ; n« sounds, or "notes," which can"be pe£ manently recorded on' a chonoarnph record. :.Then to complete*the riagj.-: process, if this, record is plaved into" a televisor' the original moving scene which caused the sound is reproduced on the screen of the televisor Mr Baird has recently", rleroted much time and. study to- lb* effort to evolve-per-fection of the nhonovi&o r , and the result of the coming "demonstrations, with this apparatus lsbein?'eagerlv awaited by devotees of applied science.