PHOTOGRAPHY OF AQUATIO ANIMALS, 55 
of screws against a rubber packing on the end of the box, so that the joint between 
cover and box is made water tight. The rubber bag used in the first apparatus 
seems to have been found unnecessary and is at any rate omitted. At the back 
of the cover there projects a handle (M) by the manipulation of which the plates 
may be changed. On the top at V is a sight by means of which the camera may 
be directed at the desired object. Within the box at the back is a magazine plate 
holder for six plates. This is represented at the left at C Hin figure 9. It is so 
arranged that when a plate has been exposed it may be made to fall forward by 
turning the handle shown at M in the central figure. A second plate is at the 
same time pushed into place by springs. When this has been exposed a second 
turn of the handle allows the plate to fall and a third plate comes into place. Six 
plates may thus be exposed without opening the box. On each side of the plate 
holder are two cleats (gl). These glide upon two rails on the inside of the box, one 
on either side, so that 
the plate holder may be 
moved back and forth 
on the rails away from 
the lens or toward it. 
By means of a set screw 
the plate holder may be 
firmly clamped at any 
point on the rail. The 
camera is focused by 
means of this movement 
of the plate holder. To 
prevent reflection of 
light from the lower 
. s 7 . Fig. 5.—Boutan’s third apparatus (1898). A, metal camera box; M, handle control- 
side of the sur face film ling the changing of plates; MO, handle controlling the shutter; O, opening for 
of the water into the the lens; P, feet for supporting the apparatus; V, sight; X, points of attachment 
4 | d 5 . of the hood AB; CII, magazine holder for six plates; gl, cleats by means of 
camera there 1s pro- which the holder glides ona rail inside the box; pl, plates; f, pin which holds the 
vided a semicylindrical front plate in place. (Copy of fig. 3 in Boutan, 1898.) 
shade shown at A B on the right in figure 5. It may be attached to the front of 
the box above the lens by the arrangement shown at X. 
It is not possible to focus after the box has been closed in order to immerse it. 
Consequently one of the rails upon which the plate holder moves must be provided 
with a scale. The divisions on this scale correspond to different distances between 
the lens and the object to be photographed. When the plate holder is set at a 
certain division of the scale the camera is in focus for objects at a distance of 4 
meters: when set at another division for objects at 2 meters. It is therefore 
necessary to determine before the camera box is closed at what distance the object 
is to be photographed and to focus by setting the plate holder at the corresponding 
division on the scale. While the box is immersed this focus cannot be changed. 
The divisions to be marked on this scale were obtained by focusing on submerged 
objects while the front of the camera was also submerged. This necessitated the 
use of special devices, which need not be deseribed here. 
