256 Fortieth Annual Meeting 



angle of 45 degrees with the long axis of the caison. In the 

 front of the lower end would be placed a window made of 

 inch thick plate glass, to withstand the pressure of the 

 water and to add weight at the proper place. Beneath the 

 caison, which is perfectly water-tight, enough weight would 

 be attached to sink the camera-water-glass-caison until it 

 would rest lightly on the bottom. In the upper end I would 

 mount a grafflex camera provided with a long focus lens 

 and an automatic plate-shifting device and magazine to 

 carry at least half a dozen plates. The device would, of 

 course, give but a limited photographic field, but would be 

 simple in plan and should demonstrate whether or not the 

 theory was workable. If it should yield encouraging 

 results, I would attempt a still further improvement by 

 placing the plate glass window horizontally in the caison, 

 above the mirror, and arrange specially ground lenses in 

 front of the mirror so that both would be bathed in the 

 water and would bring into focus on the mirror a larger 

 field which would be sent by it through the plate glass win- 

 dow into the eye of the camera. Should it then develop 

 that the light on the bottom was insufficient for rapid ex- 

 posure, I would add to the equipment a specially designed 

 flashlight gun. It would be a stout, square, water-tight box 

 with a door in one side and a plate glass window in the 

 front. From the top would extend a pipe to the open air, 

 perhaps three inches in diameter, to allow the smoke to 

 escape. The marine flashlight would be weighted to cause 

 it to just rest on the bottom. The flash powder, held in a 

 safety magazine, would be ignited when desired by blowing 

 a jet of the powder over the small pilot light, the whole 

 being operated from above the surface of the water. 



Speculations such as the foregoing are opened here for 

 the inventor, photographer, and physicist who may have the 

 knowledge, interest, and funds with which to experiment in 

 this interesting field, that lies just beyond the border line of 

 what is known to be possible in aquatic photography. 



But to return from theory to achievement. Enough was 



