VINTAGE 1975s LOGARITHMIC SLIDE RULE Logarex USSR SOVIET

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Will I bring it to your attention LOGARITHMIC SLIDE RULE Logarex USSR SOVIET
In 1622, William Oughtred (March 5, 1575 - June 30, 1660) created perhaps one of the most successful analog computing mechanisms - the slide rule. Otred is one of the founders of modern mathematical symbolism - the author of several notation and operation signs, standard in modern mathematics:
The multiplication sign is an oblique cross: ×
The division sign is a forward slash: /
Parallelism symbol: ||
Short notation of functions sin and cos (previously written in full: Sinus, Cosinus)
The term "cubic equation".
"All his thoughts were focused on mathematics, and he was constantly pondering or drawing lines and shapes on the ground ... His house was full of young gentlemen who came from everywhere to learn from him."
Unknown contemporary of Otred
Otred made a decisive contribution to the invention of an easy-to-use slide rule by proposing the use of two identical scales sliding along one another. The very idea of ​​a logarithmic scale was previously published by the Welshman Edmund Gunther, but in order to perform calculations, this scale had to be carefully measured with two compasses.
Gunther also introduced the now generally accepted notation log and the terms cosine and cotangent. In 1620, Gunther's book was published, where a description of his logarithmic scale was given, as well as tables of logarithms, sines and cotangents. As for the logarithm itself, it was invented, as you know, by the Scotsman John Napier. Seeing the bewilderment of Forster, who highly appreciated this invention, Otred showed his student two calculating instruments he had made - two slide rule.
Gunther's slide scale was the progenitor of the slide rule and has undergone multiple revisions. So in 1624, Edmund Wingate published a book in which he described a modification of the Gunther scale, which makes it easy to square and cube numbers, as well as to extract square and cubic roots.
Further improvements have led to the creation of a slide rule, however, the authorship of this invention is disputed by two scientists, William Oughtred and Richard Delamain.
The first Otred's ruler had two logarithmic scales, one of which could be displaced relative to the other, stationary. The second tool was a ring, inside which a circle rotated on an axis. On the circle (outside) and inside the ring, logarithmic scales “rolled into a circle” were depicted. Both rulers made it possible to do without compasses.
In 1632, Otred and Forster's book "Circles of Proportions" was published in London with a description of a circular slide rule (of a different design), and a description of the rectangular slide rule by Outred was given in Forster's book "An Addendum to the Use of a Tool Called" Circles of Proportions ", published in the following year.
The ruler of Richard Delamaine (who was at one time Otred's assistant), described by him in the pamphlet "Grammelogy, or Mathematical Ring", which appeared in 1630, was also a ring, inside which a circle revolved. Then this brochure with changes and additions was published several times. Delamaine described several variants of such rulers (containing up to 13 scales). In a special recess, Delamain placed a flat pointer that could move along a radius, making it easier to use a ruler. Other designs have also been proposed. Delamain not only presented the descriptions of the rulers, but also gave a calibration methodology, suggested ways to check accuracy and gave examples of using his devices.
And in 1654, the Englishman Robert Bissaker proposed the construction of a rectangular slide rule, the general view of which has survived to our time ...
In 1850, a nineteen-year-old French officer, Amedeus Mannheim, created a rectangular slide rule, which became the prototype of modern rulers and provides accuracy to three decimal places. He described this tool in the book "Modified Ruler", published in 1851. For 20-30 years, this model was produced only in France, and then it began to be produced in England, Germany and the USA. Soon, Mannheim's lineup became popular around the world.
For many years the slide rule remained the most massive and accessible device for individual computing, despite the rapid development of computers. Naturally, it had a low accuracy and speed of solution in comparison with computers, however, in practice, most of the initial data were not accurate, but approximate values ​​determined with varying degrees of accuracy. And, as you know, the results of calculations with approximate numbers will always be approximate. This fact and the high cost of computing technology allowed the Slide rule to exist almost until the end of the 20th century.
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