PROPORTIONAL DIVIDERS.
These dividers differ from the ordinary ones shown in [figs. 169 and 170] in that they are provided with four steel points, one pair of which being set to the full dimension will be reproduced by the other pair, but in a smaller, or reduced size.
[Fig. 171] are “bisecting” dividers, being proportional dividers, which, when open, one end measures double the distance of the other.
[Fig. 172] are proportional dividers; the points at one end are capable of being changed, to measure practically any desired proportion at the other end, by altering the position of the pivot where the legs cross one another. The lower connecting link is a micrometer adjustment, for minute measurements.
[Fig. 173] are proportional dividers which are marked for the proportions of lines and radii of circles, being provided with a rack movement for adjustment.
[Fig. 174] represents three-leg dividers, used for taking the position of three points; this instrument is very useful in finding the position of a point in a figure.
Fig. 171.—Fig. 172.—Fig. 173.—Fig. 174.
Fig. 175.—Fig. 176.—Fig. 177.—Fig. 178.—Fig. 179.