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BIKD PHOTOGRAPHY 



of space than a circle, as a small end can face the nest, and there is ample room for the worker 

 to sit or stand behind the camera. 



I have another form of frame that makes a circular tent. It has three uprights, each 

 consisting of two parts three feet six inches long. The one a brass tube (A, Fig. 1), the other 

 an iron rod (B, Fig. 1) fitting into it. A thumb-screw (C, Fig. 1) fixes them so that the height 



B 



FIG. 1. 



of the tent may be anything from three feet six inches to nearly seven feet, according to 

 how much of the iron rod projects from the brass tube. One end of the rod is pointed to go 

 into the ground. Projecting from the top end of each upright is a piece of iron rod (D, Fig. 1) 

 screwed to take a butterfly-nut (E, Fig. 1). The three uprights are connected on top by 

 three lengths of flat spring steel about three feet long. These have at each end a fixed brass 

 loop or ring (F, Fig. 1). Two of these looped ends, one above the other, fit on to the screwed 



B 



FIG. 2. 



end-piece on each upright. Loosely put together the frame forms a triangle (A, Fig. 2), but 

 when the flat steel connecting pieces are sprung outwards in their centres and the butterfly- 

 nuts screwed down holding them firmly as sprung, the whole forms a circle (B, Fig. 2). I 

 describe these two portable tents as guides, but individual ingenuity will suggest many ways 

 of constructing frameworks. 



