s freely, so that when the weight
of the foot is placed upon the trigger outside the door that end is forced
down which pushed the end attached to the shaft up; this pushes the shaft
up and the shaft pushes _the latch up_; thus the door is unfastened. The
diagram to the left in Fig. 200 shows the edge of the door with the
trigger on the outside, the shaft upon the inside. The diagram to the
right in Fig. 200 shows the inside of the door, the end of the trigger,
the shaft, the latch, and the catch.

The Latch-String

In the preceding locks and fastenings, no matter how generous and
hospitable the owner may be, his latch-string never "hangs on the
outside," but in this one the latch-string literally hangs outside and any
one may enter by pulling it (Figs. 193 and 194). But when the owner is in
and does not want to be interrupted he pulls the string in, which tells
the outsider that he must knock before he can be admitted. This simplest
form of latch has been here put upon the simplest form of a door, a door
with a wooden hinge made by nailing a round rod to the edge of the door
and allowing the ends of the rod to project above and below the door. In
the sill log below the door a hole about two inches deep is bored to
receive the short end of the hinge rod; above a deeper hole is bored to
receive the long end of the hinge rod. To hang the door run the long end
up in the top hole far enough to lift the door sufficiently to be able to
drop the lower end of the hinge rod in the lower hole. Your door is then
hung and may swing back and forth at your pleasure. Notwithstanding the
fact that such a door admits plenty of cold air, it is a very popular door
for camps and is even used for log houses.

Fig. 193. Fig. 194. Fig. 195. Fig. 196. Fig. 197. Fig. 198.

Fig. 199. Fig. 200.

[Illustration: Foot and thumb door-latches.]

Simple Spring-Latch

A simple form of spring-latch is shown by Fig. 196, as you may see, _A_ is
a peg driven into the door-jamb. It has a notch in it's outer end so that
_B_, a piece of hickory, may be sprung into the notch; _B_ is fastened to
the door by a couple of screws. By pushing the door the latch will slide
out of the rounded notch and the door opens. When you pull the door to
close it the end of the spring strikes the rounded end of the _A_ peg and,
sliding over it, drops naturally into the slot and holds the door closed.
This form of latch is also a good one for gates.

Better Spring-L