Siemens Pointer Telegraph

1847 · Dial Telegraph · Work 129 of 1,871

Siemens Pointer Telegraph, 1847, Dial Telegraph

A Siemens and Halske pointer telegraph in a Berlin workshop, a circular lettered dial with a single hand driven by a self interrupting contact, keys ranged around the rim of the wooden case.

What it was used for
Werner Siemens built the pointer telegraph in 1846 and had it patented on 7 October 1847; he founded the Telegraphen-Bauanstalt von Siemens & Halske in Berlin on 1 October 1847. The Royal Prussian Telegraph Directorate used the apparatus from 1854 to 1867, above all on German railways. Its political moment was the Berlin-Frankfurt line, more than 650 km long: in 1848/49 news from the National Assembly went from the Paulskirche in Frankfurt over ten relay stations to Berlin; the telegram on the imperial election arrived within the hour. Among them was the offer of the German imperial crown to Friedrich Wilhelm IV - a crown he refused on 28 April 1849, because coming from an elected parliament it was not acceptable to him.
What was new
Reading letters off a dial was not the difference - Wheatstone's ABC telegraph did that too, and untrained staff could work it. What was new was the self-interruption: both instruments ran as self-driving machines in step and advanced only once the circuit had closed again, instead of relying on a hand turning a crank evenly enough. That is precisely where Siemens had failed in 1846 with a Wheatstone apparatus, because a substantial part of the current was lost through the poorly insulated lines. On his advice Prussia decided in 1847 to lay gutta-percha insulated wires underground on a large scale, some 2,250 km; after a while the lines failed almost completely, Prussia abandoned the system, and the good cooperation with the telegraph administration ended - follow-up orders stopped coming. The firm turned abroad: in 1851 came the contract for a Russian network of about 9,000 km, built from 1853.

Further reading