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 on it, which, falling on an escapement, set the clockwork in action.

This alarum arrangement gave Soemmerring much pleasure, which he expresed in his journal with some detail. He wrote: “If the principal part of the telegraph gave me no trouble and demanded no alteration, but was ready in a few days, this secondary object, the alarum, cost me a great deal of reflection and many useless trials with wheelwork, which was driven by the streams of gas in the water to set the clockwork going, till at last I hit upon this very simple arrangement.”

Soemmerring’s alarum has not become generally known, because it is not represented on the two plates which accompany the description of his telegraph in the Memoirs (Denkschriften) of the Munich Academy, published only in 1811. These plates were already engraved before the alarum was invented. The drawings were made by Christian Koeck, who had formerly, at Mayence, been Soemmerring’s draftsman, but who now had just returned from Moscow, where he had been employed by Gotthelf Fischer for the Imperial Society of Naturalists.