attached will not attract the attention of any one who is unacquainted
with the Deming twin bolt.

XXXV

THE AURES LOCK LATCH

THE Aures lock differs from the preceding ones in the use of metal
springs, but wooden ones may be substituted; for instance, a wooden spring
like the one in Fig. 209 may be put under the bolt or latch shown in Fig.
219, which is practically the same latch; that is, if you turn the latch
in Fig. 209 upside down it will make the latch shown in Fig. 219; also, if
you take the bolt or lock _B_ in Fig. 219 and make it of one piece of wood
with a spring to it, like the one shown in Fig. 208 or Fig. 209, or make
it exactly like the one shown in Fig. 201, the Aures lock can be made
altogether of wood. But with this lock, as described below, metal springs
were used (Figs. 219, 220, and 221).

The Door

The door shows the two strings _H_ and _K_ coming through gimlet holes
near the top. Fig. 218 represents the outside of the door. The strings may
be concealed by covering their ends with a board as shown in this diagram,
but even if they are not concealed, one unacquainted with the lock will
not know how to work them in order to open the door.

_A_ in Figs. 219, 220, and 221 is the latch which is made of a piece of
wood about eight or nine inches long by about one and one half inches wide
by an inch or three quarters of an inch thick. A hole is drilled near the
centre of the latch and a screw placed through which is screwed into the
door so that the latch will extend about two or three inches beyond the
end of the door.

_D_ (Figs. 219, 220, and 221) is a catch or stop which is fastened to the
door-jamb and keeps the end of the latch from flying too far up to lock
the door.

_B_ (Fig. 219) is the key which is made of the same sort of wood as the
latch; a hole is drilled in this also but it is here placed about one inch
from the top. A screw is run through this, as in the hole in the latch,
and screwed into the door (Fig. 219).

Fig. _C_, 219 is a small block of wood on which a steel-band spring has
been screwed to keep the key in its proper place. The block is screwed to
the door a short distance above the top of the key.

Fig. _J_, 219 is a nail or peg placed in the door close beside the key
when the key is vertical; this is intended to prevent the key from being
shoved over too far by the force of the band spring _F_.

Fig. 219 _L_ is a steel wire spring (a window-shade spring wi