lear that the various of different kinds of figures can be wheels may be designated by im- automatically traced. aginary letters for the sake of easy | Within the range of this instru- reference. When paired wheels are he _ = ment are all the figures'of a one- mentioned, the letter indicating the… … mesh with the wheel B, that wheel system from getting a monopoly A PERSPECTIVE VIEW OF THE CAMPYLOGRAPH. and rendering the employment of turns at half the speed of the wheel other systems impossible, was open- A. This pair of wheels may be (EB), (£f),.(C), then the wheel C turns four times ed on…
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