| Faber-Castell 1725 | |
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Front |
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Logo on the back |
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| Box | |
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| Length | 34 cm |
| Number of scales | 7 |
| Country of origin | Germany |
| Country of manufacturing | Germany |
| Year of manufacturing | 1950 |
| Status of the slide rule | Normal signs of use |
| Material of the slide rule | Plastic |
| Type of cursor | Clear plastic with metal pointer |
| Status of the box | Normal signs of use |
| Status of the manual | None |
| Collection number | 163 |
| Further comments | This is a very unusual slide rule. I
have not been able to find the type 1725 in any list, book or website.
According to Dieter von Jezierski, THE expert in the area of Faber-Castell slide rules, it is not a real slide ule but a socalled "Bruchgrenzenmaßstab". A calcualtion device used in the mining industry to compare dates for limits of breaking with various angles of inclination. |
