The Signalling Commission

In 1797, the Danish Navy established a Signalling Commission, which was given the task of improving communications between ships and between ships and land. The Commission dealt with flags aboard ships and with lighthouses. But in 1799, the optical telegraphs came to its attention and members of the Commission made several sketches of optical telegraphs, in competition with Walterstorff.

Sketch of Captajn Obelitz´s telegraph, 1799. The Danish National Archives.

One of the Signalling Commission´s proposals for a optical telegraph. The optical telegraph devised by Ove Obelitz, a member of the Commission, operated on the basis of three figures that could be hoisted on a large stand. The figures were given values - up to 99,999 different ones - according to their position when hoisted. Obelitz´s proposal was rejected by the other members, however.

Sketch of Captain Fisker´s optical telegraph, undated. Post & Tele Museum.

The winning proposal for a optical telegraph. Each of the 18 clappers has its own numerical value, from 1 to 20,000. By adding up the values of the lowered clappers, a number from 1 to 42,221 is obtained, more signals than any other type of optical telegraph was capable of sending at that period. In the summer of 1799, a test version of the telegraph was set up on the Kvintus Bastion in Copenhagen, and after a trial period the final version was ready.