Abstract
MESSRS. J. J. GRIFFIN AND SONS, LTD., of Kingsway, London, have sent examples of two slide-rules which they are introducing at a very low price—the longer one, which is 25 cm. in length, at 2s., and the shorter, which is 12·5 cm. in length, at is. These rules with their slides are made of card, and the divisions are printed. In point of clearness and accuracy they are nearly equal to the best rules divided on celluloid, and they are vastly superior to the old-fashioned box-wood rules of thirty or forty years ago. In each case the upper lines of the slide and of the rule go from 1 to 10 twice over or from 1 to 100, being what are called “A” and “B” lines, while the lower lines of the slide and of the rule are on twice the scale, being “D” lines. Each is provided with a cursor with chisel pointers both to right and left. The back of the slide and all the remaining spaces on the rule are left plain. The accuracy of the surfaces of juxtaposition is specially noteworthy, and is greatly in excess of what is generally associated with card structures. Each is provided with a paper imitation-leather case. With rules such as these, the real utility of the slide-rule may, it is hoped, be brought home to thousands to whom the expense of the now nearly universal celluloid rule is prohibitive; it may even be hoped that some daring mathematical master in a public school may see fit to; inculcate the wholesome practice of making calculations not vastly more accurate than any possible knowledge of the data can be, and use rules such as these both to exemplify the idea and to let schoolboys know how the daily arithmetic of the laboratory and of the workshop is carried out. Masters should also find them useful for curve tracing on squared paper, as the coordinates of any parabola or rectangular hyperbola, or of any curve representing the law of inverse squares, can be read off from the rule with a single setting of the slide.
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New Slide-Rules . Nature 77, 500–501 (1908). https://doi.org/10.1038/077500b0
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DOI: https://doi.org/10.1038/077500b0