| 摘要 |
A disc computer having a lower disc with a peripheral scale at the edge of its upper face and an upper disc rotatably and concentrically secured at its center to the first disc. The upper disc being smaller in diameter than the lower disc and having a peripheral scale at the edge of its upper face for use in conjunction with the scale on the lower disc. The upper disc has a pair of diametrically opposed, transparent lugs extending from its peripheral edge substantially to, but not beyond the peripheral edge of the larger bottom disc to facilitate manipulation of the upper disc.
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