Entry

Wooden scale (NG-MC-853-1) and two documents (NG-MC-853-2 and NG-MC-853-3).

The scale is a simple wooden ruler with on one side a number of different scales, and on the other a number of tables and two verniers.

The scale worked as a tidal computer, meant to replace the printed tables to solve computations in navigation. The handwritten patent application is addressed to stadholder Willem V and was signed by Rasmus Dekker. The handwritten letter of recommendation is also addressed to Willem V and was signed by Jan Hendrik van Kinsbergen (1735-1819), dated 28 July 1791.

Dekker repeatedly tried to sell his inventions to the Dutch and French governments between 1791 and 1815, but was turned down on each occasion. They were tested by Hendrik Willem Lantsheer in 1810 and a number of instruments were bought for further testing in 1814, but in 1817 the Navy definitively declared Dekker’s inventions unsuitable for the service.