More from the 1934 book, "The Compleat Goggler".

"Cameras

"With half the world gone batty on the subject of photography, you may feel
impelled to try some shots at the fishes.  The easiest way to do it is with
a movie camera enclosed in a watertight brass or galvanised iron box with
with sights on the top.  At one end of the box is a hole with a piece of
ordinary glass in it, while on the right-hand side is another hole covered
with a sheet of rubber to form a sort of limp diaphragm.  By pressing on
this diaphragm, you can touch and release the camera trigger.  Focus and
aperture have to be set in advance.  I give no details, because they depend
on the type of camera and the transparency of the water.  The basic
principle is simple, but of course a certain amount of experimentation is
necessary before you can count on results.

"With a rig of this sort, Commandant Le Prieur has taken some fine pictures
of fish, divers, and naval salvage-operations.  He is now working on a box
for his Leica, with some remarkably ingenious devices for winding,
focussing, adjusting aperture and shutter speed, etc."

What hurts me is the fact that Le Prieur actually managed to capture images
on film, whereas I - with the benefit of almost seventy years of
technological advances - still struggle!  :-)

Strike