Slide rule - the main counting device of the XX century

2024 Author: Priscilla Miln | [email protected]. Last modified: 2023-12-16 00:21

In the age of computer technology, most of the calculations in the design of equipment are fully automated, engineers can only enter the required parameters through a convenient interface.

The 20th century was called differently. It was atomic, cosmic, and informational. Aircraft designers improved aircraft, and they turned from clumsy biplanes into fast-moving supersonic MiGs, Mirages and Phantoms. Giant aircraft carriers and submarines began to surf the seas and oceans at all latitudes. An atomic bomb was tested in Los Alamos (New Mexico), and the first nuclear power plant began to provide energy in Obninsk, near Moscow. Rockets soared up…

How did the atomic bomb, rockets and jets count?

Historical chronicles show the process of working on these achievements. Scientists and engineers in white coats, standing at the drawing boards and sitting at tables littered with drawings, make the most complex technical and scientific calculations on adding machines. Sometimes in the hands of Tupolev, Kurchatov or Teller suddenly turned out to be a thing unfamiliar to a modern young man - a slide rule. A photothose whose youth passed in the post-war decades, up to the 80s, also fixed this simple object, which successfully replaced the calculator while studying at the institute or graduate school. Yes, and dissertations were also considered on it, on my own.

What is the principle behind the slide rule?

The main principle of this wooden object, carefully pasted over with celluloid white scales, is based on a logarithmic calculation, as the name implies. More precisely, on the decimal logarithm. After all, everyone who taught higher mathematics knows that their sum is equal to the logarithm of the product, and, therefore, by correctly applying divisions to moving parts, one can ensure that multiplication (and hence division), squaring (and extracting the root) become a simple matter.

The slide rule became popular back in the 19th century, when ordinary abacus was the main means for making calculations. This invention is a real find for the then scientists and engineers. It didn't take long for them all to figure out how to use the device. In order to learn all the intricacies and reveal its full potential, fans of the new counting mechanism had to read special manuals, quite voluminous. But it was worth it.

Rulers are different, even round ones

Nevertheless, the main advantage that a slide rule has is its simplicity, and therefore reliability. Compared to other methodscalculations (until there were calculators), operations were performed much faster. But there are also moments that should not be forgotten. Calculations can only be made with mantissas, that is, the integer (up to nine) and the fractional part of the number, with an accuracy of two (three, for those who have very good eyesight) decimal places. The order of the numbers had to be kept in mind. There was another drawback. Although the slide rule is small, it is difficult to call it a pocket device - 30 centimeters after all.

However, the size did not become an obstacle for inquisitive minds. For those who, by the nature of their activities, must always have a counting device with them, a compact slide rule was invented. A circular scale with hands gave it a watch-like appearance, and some models of expensive chronometers contained it on their dials. Of course, the capabilities of this device and its accuracy were somewhat inferior to the corresponding parameters of the classic line, but it could always be carried in a pocket. Yes, and it looked more aesthetic!