| Name and Model Number | Hemmi 405 Chemical Slide Rule for Portland Cement |
| Country of Origin | Japan |
| Date of Manufacture | 1958 - 1959 |
| Front Scales | 7 scales - chemical compounds |
| Back Scales | 7 scales - chemical compounds |
| Scale Length | 25 cm |
| Type of Rule | Slide Rule |
| Construction | Celluloid on bamboo |
| Area of Use | Chemical |
| Comment | For Portland cement composition.
No logarithmic scales. Instruction Manual published by Portland Cement Association, Skokie, Illinois, May 1959. |
| Rarity | RRR |
| Donor | Collection of Ron Knapp |
| Match Number | 151 |
| 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. |