C.H. Webb:The Adder - Circular Calculator - Slide Rule

C.H. Webb "The Adder"
Circular Calculator
"Saves Time and Brain Labor"
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**Great Condition**Nice Patina**
Auction winner will also receive nicely printed copies of the patent diagrams and advertisements that we found.
Check out our other auctions for more slide rules
From the Journal of the Franklin Institute, 1870
Machine for Addition.--By C. H. Webb, of New York.-- This very simple and efficient piece of mechanism is represented by Fig. 1 in its exterior appearance, and by Fig. 2 as regards its internal mechanism. In the first place, as regards the exterior, A, Fig. 1, represents a plate with 100 holes around its periphery within a divided circle having 100 degrees in its circumference. A small steel point being inserted in one of the holes, enables us to rotate the disk in the direction of the arrow until motion is arrested by the steel point coming to the stop at 0, w the small hand points in the figure. Suppose the disk set with this hand and 0 point of the disk opposite the 0 of the divided circle, and suppose that the steel point is now inserted opposite the figure 10 of the outer circle, and the disk moved until the point strikes the stop. The disk will clearly be moved around a distance corresponding to 10 holes or divisions, and an outer rim of the same which lies under the divided
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