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The first logarithmic calculating rules did not slide at all This ” Gunter’s Rule ” was the original device introduced by Edmund Gunter in , which remained in use for some two centuries. This idea remained for three centuries at the heart of every slide rule made. This instrument had a variety of useful scales and tables on one side and a standard 2-foot measuring rule on the other. The logarithmic calculating function used the narrow slide in one of its legs For more, see this article. The variety of calculations required ran into a problem: to calculate multiply or divide or convert between different quantities one needs to move from a number on one scale to the number at the equivalent point on another scale. This required the two scales to touch each other, so the equivalent points could be pinpointed accurately.

## Calculators available for adoption

As is well known, Faber – Castell began to date-stamp their. Dating the rules they manufactured. Faber began to make slide rules [8], and the early s. Faber – Castell ; for convenience I will refer to the company.

Although fairly early this rule shows, in some ways, the variation in the Rietz On this rule the log scale is on the bottom of the stock and the reverse of the slide (In Faber Castell started marking the date on their rules as the year after.

Although the date codes were prominently engraved and paint-filled in the early years, from the late ‘s onward they can be hard to spot as they are only lightly engraved in small letters, often near an edge. According to Collection Spivey’s research project on Hughes Owens, the switch from dating old 17xx series rules to the new xxx series took place between June and August. Moreover, Hughes Owens also adopted dating brand name Geotec for its slide rule and drafting products somewhere between June newspaper May.

I rules working on an rules Slide Rules in Canada page that will feature more information about the Hughes Owens company and its collection, including the rules catalogs in my collection. Please stay tuned! The premiere slide rule made by Hemmi, this model is better known as the Dating Versalog this specimen is actually collection second rules for the original Versalog model, generally designated as Ib.

## Hemmi Duplex Slide Rule Retailed by Post (Versalog 1460)

There seems to be a problem serving the request at this time. Nostalgic original Keuffel and Esser slide rules with their advanced trigonometric and logarithmic scales invoke fond memories in accountants, engineers, scientists, and business consultants. Undergraduate and graduate college students majoring in math, science, or engineering who graduated prior to used this mechanical analog computer in their multiplication and division of extremely large and infinitesimally small numbers.

Slide rules, also called slip sticks, consisted of two stationary rules and an interlocked central sliding rule with scaled numbers and a clear plastic cursor with a vertical line to slide to corresponding numbers on multiple scales.

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Brand New Slide Rules. Slide rules in original plastic bags have not been cleaned or aligned. Some collectors, including myself, like having rules that have been sealed since they left the factory. The rules can be returned to condition with some metal polish on the end brackets and a wipe-down with Windex. Complete, brand new package includes slide rule, brown leather sheath, page factory instruction book, and shelf box.

Rule, case and box are brand new, factory perfect; instruction book has remnant of retail label on front cover, otherwise perfect.

## Dating post slide rules

The slide rule , or slipstick , [1] is a mechanical analog computer. The slide rule is used mainly for multiplication and division , and also for “scientific” functions such as roots , logarithms and trigonometry , but usually not for addition or subtraction. There are many different styles of slide rules. They are usually linear or circular. They have a standardised set of markings called scales. These scales are used for mathematical computations.

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An abacus used at the NIH? Yes, by Dr. Wallace P. According to Dr. Adenoviruses mainly cause respiratory illnesses but can also cause other infections such as pink eye conjunctivitis. They get their name from the human organ they were isolated from: adenoids. Rowe also described the epidemiology and clinical characteristics of these infections. Abacus, Chinese, unknown date. Robert L.

Over the course of 40 years, Berger developed a number of instruments used by scientists at the NIH.

## Suggestions for Dating pre-1920 Faber-Castell Slide Rules

In most cases dating of a particular slide rule requires consideration of several parameters. Model numbers , serial numbers , catalog descriptions , cursor types , patent dates , variants , and specials are used in combination with each other to fully identify a given rule. The following is a discussion on the subject.

Model Numbers: There were four different number series in the history of the slide rule line. Serial Numbers:.

Pre-Electronic Devices | Abacus and Slide Rules Abacus Chinese Abacus An abacus used at the NIH? Yes Abacus, Chinese, unknown date.

In most cases dating of a particular slide rule requires consideration of several parameters. The following characteristics are used in combination with each other to fully identify a given rule:. Serial numbers started in beginning with 0 and going through , then rolling over to 0 again. There were three rollovers occurring in , , and The following graph approximates the four production cycles. Dates Marked With Stars: The stars in the above chart represent benchmark dates for particular rules where their purchase dates are known.

Rules are only accepted as benchmarks if they were main sellers and usually did not sit on distributors shelves very long. Benchmark Rules: Follow links for details. It should be noted that the production rate changes at some of these benchmarks. At this time we do not have enough benchmark rules to allow approximating a smooth curve.

## Slide rule

Guide – Hemmi Date Codes. Greg’s Slide Rules. After Hemmi dropped the ‘Made in Occupied Japan” logo in about they began placing date codes on certain rules. This code took the form of a two letter code marked somewhere on either the top or bottom of the rule.

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Bob’s Calculators and Slide Rules. Search this site. Caclulated Industries. Hewlett Packard. Radio Shack. Texas Instruments. Measuring Rules.

## OS Slide Rules Slide Rule Chronograph Date

The slide rule , also known colloquially in the United States as a slipstick , [1] [2] is a mechanical analog computer. The slide rule is used primarily for multiplication and division , and also for functions such as exponents , roots , logarithms , and trigonometry , but typically not for addition or subtraction. Though similar in name and appearance to a standard ruler, the slide rule is not meant to be used for measuring length or drawing straight lines.

Slide rules exist in a diverse range of styles and generally appear in a linear or circular form with a standardized set of graduated markings scales essential to performing mathematical computations.

My collection of K&E slide rules. Additional dating information has been obtained from a variety of sources, with special thanks to Ed.

Initially used on metal-framed cursors; later on frameless “Type B”. Date thanks to Clay Castleberry and Atsushi Tomozawa. Models dissapear; model numbers above 20 introduced. Rules are marked just “Hemmi,” no longer “J. Hemmi owned many other patents, but to my knowledge, the above includes all the patent numbers which actually appeared on products. Cursors Cursors are not reliable indicators of the age of slide rules; too many broken cursors were replaced with newer models.

That having been said, it would be foolish to ignore the cursor when estimating the age of a slide rule. Here are scans of some Hemmi cursors with information about their ages. Unmarked Cursors The Hemmi cursors shown here carry no brand or maker’s identification. Tom Dilatush has compared one to several old Faber cursors and is of the opinion that the design was copied from Faber.