PHOTOGRAPHY OF AQUATIC AWIMAU8, 59 



seen that the lamps were working, the shutter was operated from the boat. In 

 this way good photographs of gorgonias were obtained at night at a depth of 6 

 meters, with an exposure of five seconds. It is not necessary that the diver should 

 descend to place the lamp in position. The same apparatus was worked successfully 

 at a depth of 50 meters, in this case the apparatus not being allowed to rest on the 

 bottom, but being held suspended from a cable at some distance from the bottom. 

 The object photographed was a canvas screen rigidly attached by rods to the camera 

 support at such a distance from the lens as to be sharply focused. When the 

 apparatus was brought to the surface it was found that one of the lamps had failed 

 to withstand the pressure so that its jacket was filled with water. With lamps 

 and camera constructed to withstand the pressure at great depths, Boutan believes 

 that an apparatus of this sort may be used at depths to which light does not 

 penetrate. The apparatus may of course be used by a diver at depths of 40 meters 

 or less, and the camera may then be directed at any desired object; but at greater 

 depths a diver can not work, and the apparatus must then of course be let down at 

 random, to photograph only what chances to be in the range of its lens. 



Boutan's work has the great merit of having demonstrated that it is possible 

 at a depth of 3 meters to obtain good instantaneous pictures by the light of the 

 sun and without the use of artificial light. He showed further that his apparatus 

 with electric illumination could be immersed and operated from outside the 

 water at depths as great as 50 meters. For work at great depths or by artificial 

 light no better apparatus is known. The faults of it, for work in shallow water or 

 at any depth to which a diver can descend, are (1) its great bulk and weight, and (2) 

 the fact that it can not be focused under water. It can not be carried about freely, 

 and for use it must be set on the bottom at a known distance from the object to be 

 photographed and must then be sighted at that object. It is unfortunate that 

 for work in shallow water Boutan did not make use of the principle of the twin 

 camera or the reflecting camera, for by using either of these devices he could have 

 made an apparatus that was portable and that could have been focused under water. 

 He could thus have carried his camera about as one carries detective cameras and 

 could have photographed submarine objects either while wading with his head 

 above water or hi moderate depths while on the bottom in a diver's suit. 



BRISTOL'S SUBAQUATIC CAMERA. 



That such a method is feasible and that it may yield better results than 

 those obtained by Boutan was suspected as early as 1898 by Prof. C. L. Bristol, 

 who immediately began work on a submarine photographic apparatus. Nothing 

 has as yet been published concerning this apparatus, and the details of its con- 

 struction are quite unknown to me. Professor Bristol kindly permits me, however, 

 to make the following quotation from a letter to me on the subject: "From the 

 first I have used a water- tight camera capable of submersion hi from 10 to 15 

 fathoms, mounted on a tripod with a universal motion, arranged so as to show the 

 picture on the ground glass as well as to focus the lens and make the exposure. 

 Moreover, a magazine attachment permits me to carry down several plates and to 

 change them after each exposure while under water. After several seasons' efforts 

 the apparatus is now very efficient and has produced excellent results. I am not 

 yet ready to publish a detailed account." 



