hold the structure up. It is doubtful whether such an arch could
be built of brick or stone without scaffolding, but with the snow
blocks it is a simple matter.



** Secret Door Lock [6]

The sketch shows the construction of a lock I have on a door which
is quite a mystery to those who do not know how it operates. It
also keeps them out. The parts of the lock on the inside of the
door are shown in Fig. 1. These parts can be covered so that no
one can see them.

[Illustration: Fig. 1, Fig. 2, Fig. 3; The Lock Parts]

The ordinary latch and catch A are attached to the door in the
usual manner. The latch is lifted with a stick of wood B, which is
about 1 ft. long and 1 in. wide, and pivoted about two-thirds of
the way from the top as shown. The latch A is connected to the
stick B with a strong cord run through a staple to secure a
right-angle pull between the pieces. A nail, C, keeps the stick B
from falling over to the left. The piece of wood, D, is 6 or 8 in.
long and attached to a bolt that runs through the door, the
opposite end being fastened to the combination dial. Two kinds of
dials are shown in Fig. 2. The piece D is fastened on the bolt an
inch or two from the surface of the door to permit placing a
spiral spring of medium strength in between as shown in Fig. 3.
The opposite end of the bolt may be screwed into the dial, which
can be made of wood, or an old safe dial will do. A nail is driven