THE METHOD OF HOMING PIGEONS. 



769 



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 dis- 

 tance from every other. A number of rectilinear figures were 



Fig. 5 



Fig. 6 



Flg ' 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 backioard or deviating from tlie 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 



VOL. XLIV. 57 



