Page:Popular Science Monthly Volume 44.djvu/787

Fig. 6. This is a shade less ideal. The searcher, supposing him to be at the center, first looks around as far as he can see, then goes straight out twice the distance at which the object is visible, and begins following circles, each one being twice the visible distance from every other. A number of rectilinear figures were

Fig. 7	Fig.8
Fig. 5. Involute of a circle, the figure suggested by Professor Story as the ideal curve of search. Fig. 6. Curve of search given by a number of persons. Figs. 7 and 8. Rectilinear search lines. The shaded portions in Figs. 5 to 8 represent parts of the field not visible without looking backward or deviating from the search curve. Dotted arcs indicate limit of vision.

received, types of which are reproduced in Figs. 7 and 8. These are a stage above the fundamentally logical. They clearly belong to the realm of the practical. We might call them "Yankee" search curves. They are practical, of course, because it is easier to follow a straight line than a curve.

A simple experiment was next devised, in which a person