| Name and Model Number | Post 1466 Ritow Manifold Slide Rule |
| Country of Origin | Made in Germany for Frederick Post Co. of Chicago |
| Date of Manufacture | 1925 -1931 |
| Front Scales | 1st half A [2nd half B inverted 1st half B inverted] 2nd half A |
| Back Scales | Back of slide: C & K --- Back of rule: Constants |
| Scale Length | 1 m (two 50 cm scales folded) |
| Type of Rule | Slide Rule |
| Construction | Closed-frame mahogany with celluloid laminate scale surfaces. 52.8 cm x 3.6 cm. Frameless cursor marked Germany. Slide friction-adjusting mechanism like that of Dennert & Pape. |
| Area of Use | Generic |
| Comment | Both "Made in Germany" & "Frederick Post Co." engraved in well beneath slide. Maker most likely Dennert & Pape.
Very unique extended scale arrangement of half & inverted scales to achieve a 1-meter long scale on a 50-cm slide rule. Scale arrangement patented by Herman Ritow for Frederick Post Co. |
| Rarity | RRRR |
| Donor | Collection of Ed Chamberlain |
| Match Number | 175 |
| 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. |