PHOTOGRAPHING NESTS AND EGGS 31 



subject will not show one the actual actinic power 

 of the light at the time of making the exposure. 

 Neither will it show how fast is the plate we are 

 using, for plates, especially the isochromatic, vary 

 greatly in their rapidity. 



To go back to our subject. Any nest placed in a 

 bush within four or four and a half feet of the ground 

 is usually an easy subject, but when the distance is 

 greater the difficulties increase. Extension legs to 

 the tripod will be of great help if the nest is not 

 more than six or seven feet from the ground. When 

 higher than that it is usually necessary to attach the 

 camera to a branch. This is done either by means 

 of a ball-and-socket arrangement, such as is used for 

 attaching the camera to a bicycle, or by fastening the 

 tripod to the branches ; the latter, however, is an awk- 

 ward and troublesome thing to do. In case there is no 

 branch in a suitable position, the difficulty can be 

 overcome by lashing a stout stick, which should be 

 forked at one end, across from branch to branch, and 

 attaching the ball and socket to this. Or if this is 

 not possible, set an upright forked stick into the 

 ground so that the crotch is at the desired height. 

 Then the horizontal pole may be attached to a con- 

 venient branch at one end, while the other end rests 

 in the upright crotch, or, if more convenient, two of 

 these forked sticks may be used. In this way, if the 

 camera is above our reach, the difficulty of arranging 



