PHOTOGRAPHY OF AQUATIC ANIMALS. 63 



two-pronged fork. The stem may be pulled in and out in the stuffing box through 

 a distance of about three-quarters of an inch. When the stem is pushed in, the 

 prongs of the fork engage hi two holes drilled hi the focusing head of the camera. 

 By turning the milled head on the outside of the box the camera may then be 

 focused. On the opposite side of the box is a second but smaller brass head from 

 which a stem passes through a stuffing box to the interior of the box, and termi- 

 nates in a flat disk. The disk lies opposite the release pin of the camera by which 

 the mirror and shutter are set in motion. A light spiral spring wound about the 

 stem between the outer head and the stuffing box keeps the stem thrust outward 

 to its full extent. Pressure on the outer head causes the metal disk to strike the 

 release pin so as to make the exposure. 



In order to use the box, it is necessary to attach to it a weight heavy enough 

 to submerge all but about the upper 6 inches of the hood. In the experimental 

 apparatus used this weight was made by folding sheet lead to form a flat mass of 

 the dimensions of the bottom of the box. The weight (not shown hi the figure) 

 was made slightly wedge shaped lengthwise and was attached to the bottom of 

 the camera by wires passing beneath it and soldered at their ends to the sides of the 

 box. As the camera would, in use, usually be pointed slightly downward, the 

 thicker end of the weight was placed in front, so that the box floated with its front 

 end somewhat lower than its back end. 



USIN'G THE APPARATUS. 



The apparatus was used hi the following manner: The magazine plate holder 

 containing twelve plates was attached to the camera, the mirror depressed, the 

 shutter set at the desired speed and width of slot, and wound. The dark slide was 

 then drawn from the magazine holder, and the camera, thus made ready for an 

 exposure in air, was placed in the box. Metal cleats soldered to the bottom of the 

 box brought it always to the same position. The head on the right of the box 

 was then pushed in until the fork engaged in the holes in the focusing head of the 

 camera. The top was then put on the box and clamped down by the wing nuts as 

 firmly as possible. The apparatus thus made ready was, when in air, as heavy a 

 load as one man could conveniently carry. It was carried to a boat or, if it was to 

 be operated near shore, to the shore. In working with the help of a boat the 

 operator wades on or near the coral reef with his head and shoulders above the water. 

 The boat, with an attendant on board, is anchored near. The operator, with the 

 help of a water glass, now seeks a favorable place for operations. As he moves about 

 the reef, the fish at first seek shelter in the dark recesses of the coral rock, but if he 

 selects a favorable place and remains quiet they soon reappear. They are at 

 first wary, but soon grow bolder and after half an hour or so pay but little atten- 

 tion to him. There is a great difference in wariness among different species of fish. 

 At first only one or two species appear, demoiselles and slippery-dicks usually, then 

 the number of species gradually increases until the shyest butterfly-fish and parrots 

 come within 6 or 8 feet of the operator. He then has the camera passed to 

 him from the boat. It floats with the upper part of the hood protruding and 

 (fig. 1 , pi. v) may be easily turned toward any point on the horizon or even tilted so as 



