Jan 1943

THE NATURAL SCIENCE SOCIETY. Committee : T. J. WALL, Esq., M.A., B.Sc. (Chairman), T. B. BOULTON (Secretary), Dr. B. G. WHITMORE, M.A., B.Sc. This term, as is natural, science has had to give way somewhat to the arts in the form of the School Play, so that the programme of the Society had to be somewhat curtailed.

R. E. Dodd resigned his secretarial post at the beginning of the term because of pressure of work. He has held this position since the Society was inaugurated in the Easter Term of 1941, and during the last two years he has done a great deal towards setting the Society on its feet.

One open meeting was held this term. The subject was " The photo-electric cell: its principle and applications."

The lecture was delivered by the secretary, and was one of the most successful ever given to the Society.

The principle of the cell was first explained and demonstrated with a suitable apparatus. The principle of the thermionic valve was then explained, with a demonstration of its purpose in the relay system, which works some mechanical apparatus when the light is cut off from the photo-cell.

The lecturer then proceeded to the applications of the cell, and the following were demonstrated :(1) Burglar alarms which operated when a beam of light was broken. Some amusement was caused by various members of the audience attempting to reach a bottle of beer without ringing a bell.

(2) Talking pictures. This was done •by a rotating disc which alternately cut light off from and let it fall on the photo-cell, thus causing the current in the latter's circuit to vary, which buzzed a loud speaker.

Several other applications were discussed and the epidiascope used to illustrate them.

The lecturer thanked Dr. Whitmore for help with the demonstrations.

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