PK Cable Map 1880's

PK Cable Map 1880's

Thursday, 24 November 2011

The Airgraph

As the Second World War progressed, Allied commitments in Africa, India and Burma grew heavier, and the distance of the fighting forces from home necessitated the invention of a new mail delivery system for the Middle and Far East, that would not involve a voyage by ship around the Cape of Good Hope that could take anywhere from four to six months. By way of a response to this intolerable situation, the GPO and the RAF devised a new system of air mail communication with troops stationed overseas - the Airgraph.

The problem, as the GPO saw it, was how to send hundreds (if not thousands) of letters in the space that would ordinarily be required for one. The solution was 'micro-photography':

The sender begins by asking his local post office for an airgraph form. This is handed to him with a 'stern injunction not to fold or crease it, and to write distinctly'. Once filled in, it was retured to the Post Office where it would be sent to London, 'where the real work begins...'

'A girl is seated before what looks like a flat-topped metal desk, with a slit in its surface just wide enough to admit a single form. Below the surface is a 16-millimeter movie camera, and each form, upon being dropped down the slit, automatically switches on an electric light which illuminates it just long enough - a fraction of a second - to be photographed by the camera.'

The final result is a strip of film 100 feet long and 16 millimeters wide, displaying a continuous succession of 1,700 airgraph photographs. The whole affair, with the little metal container in which it is coiled, weights 5 1/2 ounces. If the letters had been sent by ordinary letter-post and in their original form they would have weighed 50lbs.

'Reduced to this minimum of size and weight, the airgraphs travel by aeroplane to their destination. Here the process is reversed: the film negative is thrown by a projecting machine on to a moving strip of sensitised paper, the result this time being a series of positive photographs of the original forms, of the size familiar to all to-day.'

The strip was then cut up, each airgraph 'enveloped' and delivered. It was also possible to order duplicates of lost or damaged airgraphs - as the GPO still held the negatives.

The service was discontinued in 1945, after being deemed no longer necessary. While it was in operation, however, approximately 330,000,000 airgraphs had been sent and received.

DOC/GPO/12/2 - 'The Post Office Went to War'; 1946.