| Name and Model Number | The Mechanical Engineer Calculator -- Mid Size |
| Country of Origin | England, Manchester (distribution). Swiss made. |
| Date of Manufacture | ca. 1900 |
| Front Scales | L, A, C (2 circles), S |
| Back Scales | none |
| Scale Length | 5.7" (14.5 cm) |
| Type of Rule | Watch Type |
| Construction | Metal case with glass front, rotatable paper scales, and fixed and movable cursors. Scales rotated by main stem and cursor rotated by side stem. |
| Area of Use | Generic |
| Comment | Basic mathematical calculations.
Middle size version of the calculator. No indication of model name on the scale disc. Distributed by Scientific Publishing Co., Manchester, England. Has SCIENTIFIC PUBLISHING COMPANY MANCHESTER printed on scale disc near hub. |
| Rarity | RR |
| Donor | Collection of Dr. Paul J. Tarantolo Jr |
| Match Number | 62 |
| 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. |