Then solder the cover to the can
and punch a number of holes about 1/4 in. apart along the opposite
side from where the large hole was cut. Place this can on one end
of the trough, as shown, with the large hole up.
Some heavy wire bent in the shape of a U and fastened to the under
side of the trough at the can end will furnish supports to keep
that end of the trough the highest and place the opening in the
can close beneath the water faucet. A common pin stuck through one
end of the film and then in the trough close to the can will hold
it in position for washing. Five minutes' washing with this device
is sufficient to remove all traces of the hypo from the film.
--Contributed by M. M. Hunting, Dayton, O.
** Wood Burning [331]
[Illustration: Burnt Wood]
Burnt wood work done with an ordinary reading glass and the sun's
rays.
** The Diving Bottle [331]
This is a very interesting and easily performed experiment
illustrating the transmission of pressure by liquids. Take a
wide-mouthed bottle and fill almost full of water; then into this
bottle place, mouth downward, a small vial or bottle having just
enough air in the bottle to keep it barely afloat.
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