50 - Cm (20 Inch) Mannheim Slide Rule By H. Morin
Item History & Price
| Reference Number: Avaluer:14318912 | Modified Item: No |
| Country/Region of Manufacture: France |
From around 1880 until the 1960’s, H. (Henri) Morin was a leading French manufacturer and re-seller of drawing and surveying instruments. Morin also made slide rules, but his are far less common than other French brands. This one is a 50 cm Mannheim, with A, B, C, and D scales on the front, with none of them labeled, S, L, and T scales on the back of the slide, with only S and T labeled and upside down with respect to each other, a 50-cm ruler on the upper, beveled edge, ...and nothing at all on the lower vertical edge, even though it is covered in the same white celluloid as the rest of the rule. The back of the slide rule is also covered with celluloid, except for ¼” strips at the upper and lower edges. In a surprise, it does not have a paper label with a table of handy constants and conversion factors stuck onto the back. “H. MORIN” and “11 RUE DULONG PARIS” are stamped into the exposed strip of wood along the lower edge on the back. At the extreme left end of that strip there is “10” stamped into the wood, and at the right end there is “4 – 37”. I don’t know the meaning of the “10”, but I’m fully prepared to believe that this slide rule was made in April, 1937. On one end of the rule, the number “24” is stamped into both the slide and one of the stators, for keeping these matched parts together during manufacturing. Under a 10x loupe, I could see evidence that the lines and tick marks were all hand-scribed, not machine stamped. There were several places where the lines overshot their targets and marks where the cutting chisel was dragged lightly across the surface leading up to where it scribed a line.
If you look closely at the second picture, concentrating on the ends of the slide rule, you will notice that the slots in the screws anchoring the celluloid to the wood are almost perfectly aligned. In woodworking this is called “clocking” the screws, and is, generally speaking, reserved for only the most OCD of woodworkers. I was not expecting to see this on a mass produced slide rule. It spooked me for a moment.
This slide rule is in very good condition, with the cracked glass in the cursor being the only significant fault. There is a piece of tape on the cursor that I am very reluctant to remove, as it may be the only thing holding a piece of glass in. The face of the rule is dirty overall, but nothing that a careful scrubbing wouldn’t remove. The 50-cm ruler may have been the most-used part of this slide rule, as there are numerous pencil and pen marks on it.
This slide rule is from the collection of Robert K. (“Bob”) Otnes, PhD, one of the founding members of the Oughtred Society and the original editor of the Journal of the Oughtred Society. It is being sold by the Oughtred Society on his behalf.
The Oughtred Society was founded in 1991 by a group of slide rule collectors and is dedicated to the preservation and history of slide rules and other calculating instruments. Membership is open to anyone. Further information about the Oughtred Society can be found at: http://www.oughtred.org/.
PayPal is the only accepted form of payment. Starting 01 Oct 2019, Ebay is collecting sales tax for the 34 states that are charging sales tax on Internet purchases.
Shipping will be by USPS Priority Mail. Shipping charges will be somewhat higher for destinations outside the USA.
If you look closely at the second picture, concentrating on the ends of the slide rule, you will notice that the slots in the screws anchoring the celluloid to the wood are almost perfectly aligned. In woodworking this is called “clocking” the screws, and is, generally speaking, reserved for only the most OCD of woodworkers. I was not expecting to see this on a mass produced slide rule. It spooked me for a moment.
This slide rule is in very good condition, with the cracked glass in the cursor being the only significant fault. There is a piece of tape on the cursor that I am very reluctant to remove, as it may be the only thing holding a piece of glass in. The face of the rule is dirty overall, but nothing that a careful scrubbing wouldn’t remove. The 50-cm ruler may have been the most-used part of this slide rule, as there are numerous pencil and pen marks on it.
This slide rule is from the collection of Robert K. (“Bob”) Otnes, PhD, one of the founding members of the Oughtred Society and the original editor of the Journal of the Oughtred Society. It is being sold by the Oughtred Society on his behalf.
The Oughtred Society was founded in 1991 by a group of slide rule collectors and is dedicated to the preservation and history of slide rules and other calculating instruments. Membership is open to anyone. Further information about the Oughtred Society can be found at: http://www.oughtred.org/.
PayPal is the only accepted form of payment. Starting 01 Oct 2019, Ebay is collecting sales tax for the 34 states that are charging sales tax on Internet purchases.
Shipping will be by USPS Priority Mail. Shipping charges will be somewhat higher for destinations outside the USA.
