![]() RRR = Very Rare - only a few known to collectors may be several years before it comes up for sale.RR = Rare - 1 of 25 collectors has one it may take a year to find an example in the marketplace.(1929 - 2004), renowned Dutch collector, author, and creator of Herman's Catalogue. In conjunction with the 'donors' the OS assigns a rarity rating to each item, based on the system devised by Herman van Herwijnen One cannot be found, simply because the iron was too valuable,Īnd was probably melted down to supply metal for the first world war. Like the Billeter, Loga, Thacher, Fowler and many others. Was quickly made obsolete by other designs that were cheaper to make and had a higher resolution in the scales This unique design which is wildly different than any of the designs that made it into broad production, The wheels and base appear to be made of cast iron. Scale length of 150 inches, or 15 times the length of a standard slide rule. The diameter looks to be about 4 feet which gives a Separately from the other, with a foot operated brake to lock the wheels Slide Rule comprising two wheels with scales on the outside edge. In the example on the right a photo from 1908 shows a Cylindrical ![]() In some cases there are historical or photographic records of logarithmic slide rules but the actual artifact This gallery is being compiled by Ted Hume and Rod Lovette. Which displays rare, not necessarily old, specimens in collections of active members's of the Many of these images in the ISRM galleries, also appear in the Society for most of the scans provided in this gallery. Thanks to the members of the UK Slide Rule Circle, the Dutch KRING and the Oughtred These may includeīoxwood, Ivory (Bone), Brass and in many instances were hand-divided by an artisan. This page contains slide rules that are very rare, hard to find or manufactured in theġ800's, earlier and later, but prior to WWII, using turn of the century materials and process. Rarities, Olde & Rare Logarithmic Calculators Gunter's Scales, Sectors, Excise & Proof Rules, Cylindrical, Etc.
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