| Name and Model Number | Fowler "Magnum" Long Scale Calculator |
| Country of Origin | England |
| Date of Manufacture | 1927 |
| Front Scales | Short C scale A A L six long C scales sine sine tangent Tangent. |
| Back Scales | None |
| Scale Length | 124 cm (49-51 inches) |
| Type of Rule | Watch Type |
| Construction | Glass face, 4 ¾ inch metal body, two turning knobs |
| Area of Use | Generic |
| Comment | The long scale gives approx 4 place accuracy, which is very high for a slide rule |
| Rarity | RR |
| Donor | Collection of Clay Castleberry |
| Match Number | 336 |
| 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. |