View Full Version : Help with 18th century instrument

12-27-2013, 11:09 PM
I wonder if anyone knows what this is, or could put me in touch with someone who may know. It was found on a shipwreck from about 1700 (Dutch). It could be a carpenters square, but the straight lines hint at some type of compass-dividers/scale use for navigation. It is hard to see on this image, but a set of dividers was used to confirm that the markers on the lower left are precisely at twice, three and four times the distance of the extent of the lines broken up until ten parts. There is some variation in the small ten parts, but it is uneven making me suspect errors rather than "features". It is not for measuring distance on a mercator projection, which would have more curvature.

The ornate ends may serve some type of purpose for rotating about a point.



12-28-2013, 12:46 AM
Very curious indeed. My first thought also is that it is a navigational tool. It is a fine mystery though and while I will ask someone I am not sure he'd know. There is a wide variety of options! I keep thinking it is probably part of a larger apparatus.

This page (http://www.dehilster.info/index.php?doc=http://www.dehilster.info/instrumenten/spiegelboog/index.html) has some navigational tools from the right era but nothing strikes me as something this would obviously belong to.