A NEW TELEGRAPHY

Dominion, Volume 14, Issue 166, 9 April 1921, Page 12

A NEW TELEGRAPHY

FACSIMILE MESSAGES BY WIRE ACCURACY AND SPEED Mr. Kermod Petersen’s recently perfected "Copy Telegraph" apparatus, at which he has been working for over four years, and which, it is claimed, can produce manuscript writing or drawings over 1000 kilometres away in exact facsimile, has stood the test at a demonstration just held at Sandefjord. “Copy telegrams" (says the “Manchester Guardian”) were transmitted on the lines Sandefjord-Christiania, Christiansun-Ar-endal Skien. and Sandefjord again. These telegrams included pictures as well as messages. By the new apparatus, it is said, a message which requires three hours to send over the wires in the ordinary way can be dispatched in twenty minutes.

Mr. Petersen’s invention is founded upon an alternating current and an exact synchronising of apparatuses. The continuous transmission of messages between Christiana and Trondhjem for 24 hour® would require by the ordinary system 117 telegraph operators. By the Petersen apparatus it would require only 16. With any other system the contents of the telegrams must pass once at least through the human brain, and here it is, of course, that errors may (and do) arise. With the "Copy-Telegraph” the messages are not subject to the. human factor. All is done by mechanical means. In practice the new system would naturally adopt as its unit of charge or payment, not a given number of words, but the amount of space occupied. Forms of various sizes at varying prices would probably be issued by the postal authorities for use by the public. There would be no counting of words or payment over a counter. The form filled in would be handed in. and the message dispatched in facsimile.

The process is as follows: —The forms are placed with the inscribed side outwards on a metal cylinder already prepared with a membrane sensitive to light. The cylinder is then exposed to. a strong light, which, penetrating through tho paper,'engraves the writing on the cylinder. The manuscript being removed, the roll is treated with a special developer which "rusts” or eats into the brass, causing the lettering (or the lines of a drawing) to come out in a green colour After washing and drying the cylinder is placed on the dispatching apparatus very much like a photograph cylinder. Over the cylinder an electric current is passed out on to the wire and so communicated to the receiving apparatus. As the cylinder rotates a small needle moves on it evenly and slowly in a horizontal direction, successively touching all the points on the cylinder. Every time it touches the green writing there is a slight contraction, which is communicated to the receiving apparatus, on which sensitised paper is placed. Thus an exact reproduction of tho lettering or drawing is reproduced at the receiving end of the line. In commercial practice, it is stated, the apparatus would ’bo simpler than, that used at the demonstration. The cylinder would be superseded by metal plates. A card with metallic threads would rotate over the receiver-projector. * The chemographical process, now carried out. by hand, would eventually be made quite mechanical. The Petersen "Copy-Telegraph” can be applied also to wireless transmission.