| Name and Model Number | Keuffel & Esser 4132 Crane Sewer Rule |
| Country of Origin | USA |
| Date of Manufacture | 1910 |
| Front Scales | Special for sewer hydraulic design |
| Back Scales | Special for sewer hydraulic design |
| Scale Length | 23.2 cm |
| Type of Rule | Slide Rule |
| Construction | Open frame: 27 cm x 3 cm. Paper scales on mahogany. Riveted end posts of the early Cox patent type. |
| Area of Use | Other |
| Comment | Based on McMath's formula for amount of storm water & Kutter's formula for sewer capacity.
In 1899 to 1927 K&E catalogs. Provenance with a Hazen-Williams Hydraulic slide rule indicates an early date of c. 1910. |
| Rarity | RR |
| Donor | Collection of Ed Chamberlain |
| Match Number | 137 |
| 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. |