Full Details

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
(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.