USING THE ORDINARY CAMERA 193 



Suppose we take a typical instance of the use of 

 the tree-apparatus, which may best show how to 

 work with it. I found a broad-winged hawk occu- 

 pying the last year's nest of the Cooper's hawk, lo- 

 cated in a hemlock tree, forty feet from the ground. 

 Ascending, I found that it contained two handsomely 

 marked eggs, the full set. Had the tree been an 

 oak, with spreading forks, I could have rigged the 

 camera in the same tree, preferably about six feet 

 away, as these nests are large platforms of sticks, big 

 enough to more than fill the plate unless one can get 

 well off. In the hemlock, though, one must stay by 

 the main trunk, and a picture of the nest from 

 directly above is very unsatisfactory. So I climbed 

 the next tree, about six feet away, and, tying up the 

 focus-cloth on the farther side of it, on a level with 

 the nest, left it for a day or two, that the shy bird 

 might become accustomed to the strange article. 

 When I returned she was on the nest, showing that 

 she was ready to be photographed. 



The next thing to do was to screw the bolt into 

 the trunk of the tree on which I had left the cloth, 

 a little above the level of the nest and at right angles 

 to it, the padded end of the shank away from the 

 nest, but so that this arm would point directly at it. 

 Then I clamped the camera to the pad, aiming it at 

 the nest and allowing the front end to rest upon the 

 front shank or arm of the bolt. Having aimed and 

 focused, I tied the camera in that position with a 

 cord so it could not budge and inserted the plate- 



