48 BULLETIN OF THE BUKEAU OF FISHERIES. 



in a plane vertical to that piece. When the two pieces are separated by moving the 

 upper one on the hinge which connects them the rod slips through the opening in 

 the block and may be firmly clamped at any point in its length by means of a 

 set screw. Thus the upper piece may be held firmly at any angle to the lower 

 piece from to 90, and the camera may be pointed at the water at any 

 desired angle. The position in which the legs of the tripod are attached permits the 

 camera to be pointed directly downward in the space between the two front legs, 

 whereas if the legs were attached in the usual manner with one leg in front it would 

 be impossible to bring the camera into the vertical position. Tripods of this type 

 are to be found in the market or may be made from an ordinary tripod by any 

 mechanic. 



When the operator has placed his camera and roughly adjusted it, he should 

 set up a screen to cut off the light reflected from the surface of the water into the 

 camera. Any piece of dark fabric, a blanket, shawl, or for small objects even a 

 coat, may be used. It may be supported by hand or tied to poles stuck in the 

 bottom. The writer carries into the field a screen made by sewing together pieces 

 of black calico to form a sheet either 6 or 9 feet square. To three of the edges 

 of this, at intervals of about a foot, are sewn pieces of tape each about a foot long and 

 attached at its middle so as to leave 6 inches projecting on each side. One piece 

 of tape should be attached to each corner of the screen. Two poles are cut of 

 sufficient length to project 6 to 10 feet above the w r ater when firmly set in the 

 bottom. The poles are sharpened at one end, and beginning at the unsharpened 

 end the square of calico is tied to them by the opposite edges by means of the 

 tapes. The third side to which tapes are attached is the upper, between the 

 unsharpened ends of the poles. The poles are now thrust into the bottom on that 

 side of the camera opposite the object to be photographed and so that they slant 

 toward the camera. The screen (s s', fig. 1) is thus stretched upward from the 

 surface of the water in a slanting position, so that its upper edge is nearer the camera 

 than its lower. If the two poles are pulled together by the weight of the cloth or the 

 action of the wind so that the screen sags, a third pole tied between their upper 

 ends will keep them apart, while the tapes on the upper edge of the screen will 

 serve to attach it to the cross-pole. 



If the operator now returns to the camera he will see the screen mirrored in 

 the surface of the water. The object to be photographed should fall within the 

 limits of this mirrored image as seen from the camera. a If it does not, the screen 

 or the camera must be shifted until it does. The operator will see also the shadow 

 of the screen. This should not fall on the object to be photographed. The screen 

 should, if possible, be adjusted by slanting it or by moving one of the poles so that 

 the sun strikes it nearly edgewise, but yet does not strike that face of it which is 

 toward the camera. If this adjustment is properly made the shadow of the screen 

 is a very narrow band, which lies beneath the screen and a little nearer the camera 

 than its lower edge. The full sunlight then falls on the object while the rays from 



a Saville-Kent (1893) apparently utilized this principle when photographing with a vertical camera on the Australian 

 barrier reefs, but Rudaux (1908) stated the principle explicitly as applied in photographing in natural waters with a 

 vertical camera objects within the reflected image of the tripod top. Neither recognized the broad application of the 

 principle here described. 



