| Name and Model Number | Fowler's Calculator Scientific Publishing Co, |
| Country of Origin | England |
| Date of Manufacture | unknown |
| Front Scales | Logarithms; Short Scale; Long Scale (2 circles); Degrees (0° - 90° logarithmic) |
| Back Scales | Short Scale, Cubes and Cube Roots (3 circles) |
| Scale Length | Short scale ~ 6.7” (17 cm); Long Scale ~ 11” (28 cm) |
| Type of Rule | Watch Type |
| Construction | Metal with paper scales and glass windows |
| Area of Use | Generic |
| Comment | Double sided pocket watch calculator with single stem to rotate front
paper scales and knob on back to rotate front cursor and rear scale. Fixed cursors on both glass faces. Blankenhorn and De Cesaris Model 2AG1. |
| Rarity | RR |
| Donor | Collection of Dr. Paul J. Tarantolo Jr. |
| Match Number | 20 |
| Thumbnail (Click Picture for Details) |  |
| In conjunction with our 'donors' we assign a rarity rating to each item, based on the system devised by Herman van Herwijnen |
| (1929 - 2004), renowned Dutch collector, author, and creator of Herman's Archive, a collection of 5,000 slide rule images on CD. |
| • RR = Rare - 1 of 25 collectors has one; it may take a year to find an example in the marketplace. |
| • RRR = Very Rare - only a few known to collectors; may be several years before it comes up for sale. |
| • RRRR = Extremely Rare - a museum piece; unlikely that an example will come up for sale. |