64 BULLETIN OF THE BUREAU OF FISHERIES. 



to be pointed at a considerable angle upward or downward. The operator has now 

 merely to direct the camera at the fish, while he focuses with his right hand. He 

 must often wait some time before the fish come to the point selected or assume 

 the desired attitude. Often they may be enticed by throwing in a bait of crushed 

 sea urchins or pieces of crawfish. They are in constant motion so that he must 

 as constantly focus. He often misses a long-awaited opportunity because the fish 

 moves on or takes a wrong attitude before he has had time to focus sharply; but 

 when the favorable time comes he presses the release stem and the exposure is made. 



The apparatus must then be lifted into the boat, the cover removed from the 

 box, and the camera taken out in order to reset the shutter and change the plate. 

 It is best that all this be done by the attendant who remains in the boat, as the 

 operator is thus left free to watch the fish, while at the same time the fish are not 

 unduly frightened by the sudden movements that he would make in lifting the 

 camera. With care, however, one person may do all the work necessary. He 

 may anchor the boat near, pull it to him by means of a line, lift in the camera, and 

 make all the necessary adjustments while he himself remains in the water. If the 

 work is done near shore, the camera may be carried to shore after each exposure. 

 In that case an assistant is very desirable, since the return of the operator after 

 each absence disturbs the fish. Moreover, when near shore he is moving over the 

 rock or sand bottom, not over the clean upper surface of the reef, and every con- 

 siderable movement stirs up the bottom sediment so that some time must pass 

 before the water is again clear enough to permit an exposure to be made. If an 

 assistant is available, he may stand at a considerable distance from the operator, 

 who sends the camera box to him through the water by a quick shove. The assistant, 

 after he has carried it ashore and readjusted it, returns it in the same way. 



The opening of the box after each exposure occupies some little time, and 

 during this time favorable opportunities to make exposures are often lost. It 

 would be better if a mechanism were provided by which the plates might be changed 

 without opening the box, which would then remain in the water until twelve expo- 

 sures had been made. Nevertheless it is possible with the apparatus described to 

 make twelve exposures on coral-reef fish in about two hours, including the lifting 

 of the box from the water between exposures and opening it to change plates. 

 Any form of reflecting camera may be used and any form of plate holder. Films 

 may also be used in rolls or packs. In addition to the reflecting camera the operator 

 needs only a metal box of the structure described and of a form suited to his camera. 

 This may be made by any good tinsmith at a cost of a few dollars. 



A camera of this type inclosed in a suitable box may be held in the hand while 

 in use, or it may be set upon a tripod of heavy iron, such as is shown in figure 4. 

 Such a tripod would best have a top of the form shown in figure 2, but made of heavy 

 iron instead of wood. The operator may descend in a diving suit, as Boutan did, 

 and use the camera at the bottom in deep water either while holding it in the hand 

 or while it is supported on a tripod. There should be no difficulty in focusing 

 while looking through the plate-glass window of a diver's casque. For work on the 

 coral reefs of the Tortugas, however, the writer has found that everything may be 

 done from the surface, so that a diver's suit is quite unnecessary. He is told that 

 similar conditions exist at the Bermudas. From his own experience in fresh water 



