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File:EB1911 Telegraph - Wheatstone Punching Apparatus.jpg

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EB1911_Telegraph_-_Wheatstone_Punching_Apparatus.jpg (495 × 159 pixels, file size: 19 KB, MIME type: image/jpeg)

Description
English: In the Wheatstone automatic apparatus three levers are placed side by side, each acting on a set of small punches and on mechanism for feeding the paper forward a step after each operation of the levers. The punches are arranged as shown, and the levers are adjusted so that the left-hand one moves a, b, c and punches a row of holes across the paper (group 1 in the figure), the middle one moves b only and punches a centre hole (2 in the figure), while the right-hand one moves a, b, d, e and punches four holes (3 and 4 in the figure). The whole of this operation represents a dot and a dash or the letter “a.” The side rows of holes only are used for transmitting the message, the centre row being required for feeding forward the paper in the transmitter. The perforation of the paper when done by hand is usually performed by means of small mallets, but at the central telegraph office in London, and at other large offices, the keys are only used for opening air-valves, the actual punching being done by pneumatic pressure.
Date published 1911
Source Encyclopædia Britannica (11th ed.), v. 26, 1911, “Telegraph,” p. 520, Fig. 28.
Author Harry Robert Kempe (section author)
Permission
(Reusing this file)
Public domain This image comes from the 13th edition of the Encyclopædia Britannica or earlier. The copyrights for that book have expired in the United States because the book was first published in the US with the publication occurring before January 1, 1929. As such, this image is in the public domain in the United States.

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current16:33, 24 February 2016Thumbnail for version as of 16:33, 24 February 2016495 × 159 (19 KB)Library Guy{{Information |Description ={{en|1=In the Wheatstone automatic apparatus three levers are placed side by side, each acting on a set of small punches and on mechanism for feeding the paper forward a step after each operation of the levers. The punche...

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