2. To prevent the dividers making permanent holes in the wood at frequently used points small, circular brass inserts were sometimes used. These can be seen in the detailed image of the special scale below.
3. Whilst a basic Gunter had just one scale this has several. At the top there is a scale of inches and one of 100ths of a foot. Below that is a scale of "chords". These appear to be equivalent to the present day word "degrees" but I can find no reference to this. Further down there is a sin(e) and a tan(gent) scale. I would have expected the VS scale to be versine (versed sine from the latin to turn) but the numbers do not appear to appropriate.
4. The rule also has a number of special scales. The one shown relates to the relationship in hours from the meridian and degrees; 6 hours, a quarter of day, being equivalent to 90 degrees, a quarter of a circle. On this scale one would expect the 45 to align with 3 hours but it does not do so exactly. Whether this represents some complex navigational correction or is simply an error I do not know.
5. The reverse of the rule has a number of scales arranged arranged at different distances, possibly for scaling from maps.
This rule is from the collection of M Taylor.
Front view
Detail front left
Detail front right
Detail - special scale
Back view
Detail - back left
Detail - back right
