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Dividing engine at the Museo Galileo in Florence.. There has always been a need for accurate measuring instruments. Whether it is a linear device such as a ruler or vernier or a circular device such as a protractor, astrolabe, sextant, theodolite, or setting circles for astronomical telescopes, the desire for ever greater precision has always existed.
The large "bubble" marks are legacy technology from very early OMR machines that were so insensitive a large mark was required for reliability. In most Asian countries, a special marker is used to fill in an optical answer sheet. Students, likewise, mark answers or other information by darkening circles marked on a pre-printed sheet.
The handbook was originally published in 1928 by the Chemical Rubber Company (now CRC Press) as a supplement (Mathematical Tables) to the CRC Handbook of Chemistry and Physics. Beginning with the 10th edition (1956), it was published as CRC Standard Mathematical Tables and kept this title up to the 29th edition (1991).
All premium slide rules had numbers and scales deeply engraved, and then filled with paint or other resin. Painted or imprinted slide rules were viewed as inferior, because the markings could wear off or be chemically damaged. Nevertheless, Pickett, an American slide rule company, made only printed scale rules.
The most efficient way to pack different-sized circles together is not obvious. In geometry, circle packing is the study of the arrangement of circles (of equal or varying sizes) on a given surface such that no overlapping occurs and so that no circle can be enlarged without creating an overlap.
This machine was composed of four modified Triumphator calculators. [31] [32] [33] Leslie Comrie in 1928 described how to use the Brunsviga-Dupla calculating machine as a difference engine of second-order (15-digit numbers). [28] He also noted in 1931 that National Accounting Machine Class 3000 could be used as a difference engine of sixth-order.
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T/Maker took a different approach to most other spreadsheets: instead of embedding formulas in each cell, formulas were defined on a per-row and per-column basis in the margins. [2] Although T/Maker was released six months after VisiCalc, it was perhaps [vague] the first application to provide an 'office' suite approach to data. Tables could be ...