| Name and Model Number | Pickett N 610-ES Hydraulic |
| Country of Origin | USA |
| Date of Manufacture | 1966 - 1970 |
| Front Scales | LL1, A [B, ST, T, S, C] D, DI, K |
| Back Scales | A’, B’ [C’, D’] E’ See Comments |
| Scale Length | 6" |
| Type of Rule | Slide Rule |
| Construction | Aluminum |
| Area of Use | Other |
| Comment | For American Pipe and Construction Co.
Copyright 1966 N.D. Whitman Jr. Back scales: Diameter for Velocity Velocity, feet per second Diameter for Quantity Quantity, cubic feet per second Manning's “n” Hydraulic Gradient, feet per 100 feet |
| Rarity | RRR |
| Donor | Collection of Ron Knapp, USA |
| Match Number | 82 |
| 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. |