Cylindrical Slide Rules & Calculators

Otis King Model K



Otis King's Patent Calculators were made by Carbic Ltd of 4 Dundonald Road London SW19.
The following notes are from the instructions:-

The holder carries a logarithmic scale 66 inches long, from 1 to 10, graduated as follows :-
By 0.001 from 1 to 1.12. By 0.002 from 1.12 to 2. By 0.005 from 2 to 4. By 0.01 from 4 to 10.

In order that the range of the scale may be unlimited, decimal points are not marked. Thus the reading 212, for instance also serves for 2120, 21200, 21.2, 2.12 etc: The position of the decimal point in the answer is found be inspection or by the application of the rules given on pages 7 and 8 of the manual.
The cylinder carries 2 scales in series which are identical in all respects to the above. The point at which these 2 scales meet half-way up the cylinder is denoted by the word 'One' and is referred to as 'Middle Unity' or 'Unity.'

Weight 215gm. Extended length 26cm



Scale 423