Introduction to ISRM and Slide Rules
Our Mission, Gifting Policy and Privacy Statements
ABOUTWhat is a "Slide Rule"? A slide rule is a mechanical analog computer that was invented over 320 years agoand uses logarithmic scales to multiply, divide and calculate exponents and many other math functions, not including addition and subtraction. It is not a ruler used for linear measurements.
ISRM is the world's largest free digital repository of all things concerning slide rules and other math artifacts. There are over 7000 Images or PDF's in the ISRM Galleries and Libraries.
ISRM is dedicated to the Students, Educators, Scientists and Engineers of the Past and Those Still Present, and to promote the lost art of Numeracy by providing resources and slide rules for education and other historic institutions. We accept donations of slide rules for inclusion in the galleries. ISRM is a member of the American Association of Museums and the Association of Northern Front Range Museums. ISRM was founded in 2003.
Our apologies, the site is not yet mobile-friendly. Currently there is not enough financial or human resources to update the site to modern smart phones and tablets.
Michael Konshak, the curator and self-described "Hairy-Eared Engineer *", inspects a 2011 new arrival. What is it?
After 4 years of research, a 1939 Laboratory Specialties catalog revealed one just like it, possible made by Acu-Rule Mfg. Co.
50 years of working (1960-2010), Here's all the
math instruments the curator used in his career
Calculators Before The CPU|
|I wrote this article for the ASME Mechanical Engineering Magazine for their September, 2014 issue. I made the claim that the introduction of the Texas Instruments TI-30 scientific electronic slide rule caused the death of the slide rule, and received some flack from readers who insisted that the Hewlett-Packard HP35, released in 1972 at $395, was the first scientific calculator that killed the slide rule industry. they missed my very poorely explained point. Like the first automobiles that were produced, which were very expensive, the HP35 was like the "Winton" which was too expensive for the average worker (or student). It wasn't until Henry Ford used mass production and interchangeability of parts to bring the Ford Model T from a starting price of $700 down to $200, when he sold a million of them, did the horse and buggy begin to dissappear. The other car makers still tried to keep their prices high, like HP, and a very small percentage of the populace could afford their autos. The TI-30, with its single LSI chip, came out in June 13, 1976 for $25.00, and, for the first time, the electronic scientific slide rule cost less than the equivalent analog slide rule calculators made by K&E. It was after that that the families who owned the slide rule companies stopped manufacturing them. TI must have learned from Henry Ford, who wanted to serve the people, rather than the board of directors.|
INTRODUCTIONISRM is the world's largest free digital repository of all things concerning slide rules and other math artifacts. There are over 7000 Images or PDF's in the ISRM Galleries and Libraries. The picture of Becky holding a 1903 4 foot Ding & Frage Excise rule in front of quad monitors, shows the ISRM archiving operation, and the 17" x 11-1/2" (A3) scanner that is used. There are scans or pictures of actual slide rules and related math arifacts in the museum or provided by collectors from around the world Every specimen is different in some way. There are over 4000 unique items at present dating from 1850. Duplicate model numbers in this collection have different cursors, scales, logos or construction features. Unlike most collectors who want pristine specimens, the museum enjoys getting slide rules that are marked with the original engineer's name especially when we are told what work they were used for, even if it only helped the owner get through college.
Scales are described using the above convention
Most of the scans are larger than can be fully displayed in a default browser. Microsoft Internet Explorer 6 uses Automatic Image Resizing to make it fit without scroll bars. To display an image at full size in order to see more detail, change your settings by navigating to: Tools/Internet Options/Advanced/Enable Automating Image resizing [uncheck box].
MISSION STATEMENTThis collection of mathematical artifacts has taken quite a while and expense to accumulate and catalog. Consequently, my goal as the curator, was to not only provide research information at no charge to the public but also assist worthwhile educational and historical institutions in expanding their collections. So far, recipients have been the University of Colorado, the Math History Museum of the Smithsonian Institute, and the Computer History Museum. I also have instituted a Slide Rule Loaner program for educators which sends matching sets of 25 slide rules to schools for temporary (as long as a school year) use. The slide rules are provided through the generous abundance of collectors worldwide.
PRIVACY STATEMENTISRM does not collect any information concerning any of its visitors. In the case of Paypal transactions, only Paypal has access to your information.
Display Example of a Slide Rule Donation:
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