proportional dividers การใช้

Indirect carving is a way of carving by using an accurate clay, wax or plaster model, which is then copied with the use of a compass or " proportional dividers " or a pointing machine.
I attacked her with proportional dividers, planimeter, rotameter, Simpson's rule, Froude's coefficients, Dixon Kemp's formulae, series, curves, differentials, and all the appliances of modern yacht designing, and she emerged from the ordeal a theoretically perfect boat.