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One of the most valuable instrumen

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Dimensione file: 428 KB (1257x994 pixel)

Tipo del contenuto: pagina di rivista o giornale

Fonte pubblicazione: Popular Mechanics

Data della fonte: October 1909

Linguaggio: en (English)

Marca del contenuto: George W. Richardson  

Caricato da: Maverich il 30-05-2020
Testo originale: NEW SLIDE RULE
One of the most valuable instruments ever offered to mankind for the calculation and solution of technical problems mechanically, is the SLIDE RULE.
It was invented a half century ago, but, unfortunately (speaking from a practical standpoint) it has lain dormant since its conception, except its use amongst college students and others who have to do with advanced engineering projects.
Improvements in slide rule construction in the past has not advanced to any great extent, except it was the adoption of the runner by Mannheim; and also the advance in price. Until recently the price of a slide rule ranged from $4 to $5 and the book of instruction accompanying the rule was generally too technical for the average mechanic, engineer, or business man to comprehend. The result was that the high price made the rule prohibitive to the one class while to the other the book was not "written so you could understand it," therefore its universal adoption as a rapid calculator was not forth coming.
Mr. Geo. W. Richardson, a consulting engineer of Chicago, Ill., has wrestled with the problem for several years; believing that if he could produce a slide rule that would not be prohibitive by price, and also a book of instruction that the average person could comprehend, the demand for such a rule and book would repay him for the time spent in its development, and has not only produced a slide rule that fulfils the above requirements, but he went one step further and produced a Direct Reading slide rule. To accomplish the direct reading feature of the rule it was necessary to depart from the usual form of construction, therefore aluminum was substituted for wood and in this substitution the sticking of the slide due to changes in the condition of the atmosphere was eliminated.
A much wider slide is made permissible, and the "keys" for the solution of the different problems are printed in red upon the margins of the slide, and the upper and lower scales usually termed the A and B scales have over-lapping edges with "key holes" (sight openings) punched therein, in such a manner that when the slide is moved any selected "key" may appear in the "key hole" and when such is the case the slide rule is direct reading for that particular problem. Upon the back of the rule is printed the different problems, that may be solved directly upon the face of the rule, and the "key" for its solution is also printed in red, thus facilitating the operation. The direct reading feature of the slide rule is not limited to the problems and "keys" printed upon the back of the rule. But instead any additional "keys" or problems may be added to suit the wishes of the person operating the rule.
The "keys" or problems selected, are only those in which Mr. Richardson, has, by long experience found to most frequently come up for calculation in the office, field, or engine room, but as stated before the direct reading feature is unlimited. The operation consists simply of placing the "key" in the "key hole" and reading the answer direct without any other manipulation of the rule. For checking up your work in civil service examinations, in the shop, office, field, or engine room it has no equal. Space will not permit of going into details and naming the problems that are made direct reading, yet it is hoped that it will be sufficient to mention the fact that there are over 40 problems printed on the back of the rule which are direct reading by use of the "keys."
The book of instruction which goes with each rule is neatly gotten up, and written in plain language so you can understand it. Each problem is explained in as few words as possible, and in addition to the explanation of the direct reading feature of the rule. Much space is devoted to the explanation of how to perform the following upon the slide rule:
How to square a number.
How to find the vulgar fraction of an equivalent decimal.
How to extract the square root.
How to work proportion.
How to cube a number.
How to solve multiplication.
How to extract the cube root.
How to work division.
How to find the decimal equivalent of any vulgar fraction.
How to work the combination of multiplication and division.

The horse power of an engine.
The horse power of a water fall.
The weight to be placed upon a safety valve.
The size of a duct for ventilation.
The size of a motor to run a pump.
The horse power of double and single belting.
The size of change gears for screw cutting lathes.
The diameter of steam mains.
The percentage a customer's recording watt-meter is either "slow" or "fast."
And many others.

As Mr. Richardson is the sole inventor, patentee, and manufacturer of this direct reading slide rule he is placing the same upon the market at the extremely low price of $1.50 which includes the book of instructions.

GEORGE W. RICHARDSON, 4212 Twenty-fourth Place, CHICAGO, ILL.

george w. richardson regolo calcolatore