56 BULLETIN OF THE BUREAU OF FISHERIES. 
This apparatus, which used plates 18 by 24 em. (approximately 7 by 9 inches), 
was so heavy that it required three men to handle it easily mair. On shipboard it 
was handled by a tackle and swinging boom. It was first lowered into the hold, 
which could be closed light tight. There the plates were put into the plate holder and 
this was set at the division of the scale previously decided upon. The box was then 
closed water-tight by screwing the cover in place. To remove the moisture from 
the air within the box and thus prevent its condensation on the lens and other parts 
within, a wide-mouthed bottle containmg quick lime was kept in the box during 
the intervals when it was not immersed. The apparatus was then hoisted from the 
hold, swung outboard and lowered to the operator, who had meantime descended in 
the diving suit and selected the point at which the photograph should be made. It 
was not very difficult for the operator to handle the apparatus when it was sub- 
Fic. 6.—Showing Boutan’s method of obtaining instantaneous photographs of fish with his third ap- 
paratus. (Copy of fig. 7 in Boutan, 1898.) 
merged, since it was then buoyed up by the water. It was found easier to move it 
about when it was suspended by means of a rope to a cask floating at the surface. 
The method of using the camera for photographing fish is shown in figure 6. 
The camera, previously set for objects at a distance of 2.5 meters, was placed on 
a sand bottom at a depth of 3 meters. Here it was either allowed to rest on 
the bottom on the legs attached to it or was supported above the bottom on a 
heavy, four-legged iron frame. The camera rested on a platform within this frame 
and the platform might be so adjusted that the camera could be set at various 
heights and pointed at various angles up or down. At a distance of 2.8 meters 
from it was set up obliquely a large white screen of painted canvas stretched on an 
iron frame provided with feet. This screen served as a background for the fish. 
To attract the fish the operator then placed in front of the screen at a distance of 
about two meters a bait of crushed sea-urchins and annelids. He then pointed the 
camera by means of the sight on top and waited until the fish, attracted by the 
bait, were in such a position as to be in focus, when by means of the handle at the 
