| Name and Model Number | Dialling rule |
| Country of Origin | UK |
| Date of Manufacture | c1750 |
| Front Scales | Calculating scales |
| Back Scales | Scamozzi sector lines |
| Scale Length | 11” |
| Type of Rule | Other |
| Construction | Ivory & German silver |
| Area of Use | Other |
| Comment | A 2-foot, 2-fold used for the layout of vertical and horizontal sundials.
Dialling, or "New Improved sliding rules" with their pair of adjacent very thin slides, are amongst the most unusual 2-foot, 2-fold slide rules. This delightful ivory and German silver example with small square hinge by Wood & Lort of Birmingham (1750 – 1760) carries the full range of scales, the bottom of the two slides allowing a calculation with a pre-set calibration off-set found on the bottom edge. It is thought that the design came from the English mathematician John Browne, and it could also be used for navigation. |
| Rarity | RRRR |
| Donor | Collection of an English gentleman |
| Match Number | 65 |
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| RR | = Rare -- 1 of 25 collectors has one; it may take a year to find an example in the marketplace. |
| RRR | = Very rare -- only very few known to collectors; may take several years before one comes up for sale. |
| RRRR | = Extremely rare -- a museum piece; unlikely that an example will ever come up for sale. |