UNDER SEA WITH HELMET AND CAMERA 



or focus. The operation is as follows:— the camera is wound, diaphragm 

 set according to judgment of light condition, and focus set at, say ten 

 feet; then the camera is placed in the case, and the cover, which rests 

 on a rubber gasket, is screwed down securely. 



The diver takes the camera with him, selects his subject, places him- 

 self at a distance of ten feet, aims the camera by means of sights provided 

 on the case, and "shoots." He photographs as he pleases, bearing in mind 

 that he must stop when the camera has run down. 



Most sixteen millimetre cameras will run through about twenty-five 

 feet of film with one winding. The diver returns to his ship, wipes case 

 dry, extracts camera, inspects case for leakage, re-winds and replaces 

 camera, replaces cover, and is ready for a second descent. 



It would not be difficult to design and supply a means of re-winding 

 the camera while under water. This would save time and trouble. But 

 to have a means of changing focus and diaphragm would be too com- 

 plicated, for every outside adjustment requires a moving part to project 

 through the case. Each projection is a possible source of leakage. When 

 salt water gets into a motion picture camera it might as well be thrown 

 overboard. 



The still camera case shown in the illustration is of better construction 

 than the one above described. It was more costly because it is made of 

 cast brass and carefully machined. A Robot camera was chosen for 

 which this case was made because exposure and moving of film are both 

 under control of one button. It therefore was necessary to have but one 

 motion to operate the camera. For this purpose, a rod or plunger was 

 made to pass through the case, making contact with the button on the 

 camera. A stuffing box was provided to prevent leakage, and a spring to 

 bring the plunger back after it has been pressed down upon the button. 

 The spring should be a fairly strong one for the water pressure pushes 

 the plunger down. This difficulty occurred on the first still camera case 



