Image result for hemmi bamboo slide rule

..............................................

The Slide Rule

The slide rule, also known colloquially in the United States as a slipstick, 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 trigonomentry, 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 markings (scales) essential to performing mathematical computations.

Slide rules manufactured for specialized fields such as aviation or finance typically feature additional scales that aid in calculations common to those fields.

At its simplest, each number to be multiplied is represented by a length on a sliding ruler.

As the rulers each have a logarithmic scale, it is possible to align them to read the sum of the logarithms, and hence calculate the product of the two numbers.

The Reverend William Oughtred and others developed the slide rule in the 17th century based on the emerging work on logarithms by John Napier.

Before the advent of the elecronic calculator, it was the most commonly used calculation tool in science and engineering.

The use of slide rules continued to grow through the 1950’s and 1960’s even as computers were being gradually introduced; but around 1974 the handheld electronic scientific calculator made them largely obsolete and most suppliers left the business.

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Slide_rule

Hemmi Bamboo Slide Rule Company

Bamboo Slide Rule Company Ltd. in Japan is the oldest and most well known Japanese manufacturing company making slide rules.

Jirou Hemmi and Company was founded in 1895 and, in 1912, was granted by the Japanese Patent Office Patent No. 22129 for their laminated bamboo construction method for slide rules.

As a young company wanting exposure to a larger market, they started by selling distribution licenses to three other companies: the Fredrick Post Company of Chicago, Illinois, the Hughes-Owen Company of Canada and Tamaya & Company of Tokyo, Japan.

Tamaya, an already a well-established and well-known firm in Japan, began selling Hemmi Slide Rules in 1913.

The Hughes-Owen Company of Canada (another old firm), began selling the Hemmi Slide Rules in Canada in 1914 and in 1931, the Fredrick Post Company, of Chicago, Illinois, began selling them in the United States.

All of three of these companies were selling Hemmi-manufactured Slide Rules under their own and Hemmi's name.

Sun Hemmi also supplied re-branded OEM slide rules to other North American companies like Lafayette, Lietz, and Geotec.

Early examples may have had the "Made in Japan" or "Made in Occupied Japan" sanded off due to anti-Japanese sentiments after WWII.

It is estimated that Hemmi produced about 15 million slide rules altogether.

https://www.sliderulemuseum.com/Hemmi.htm