** Fourth-of-July Catapult [447]

Among the numerous exciting amusements in which boys may participate during the Fourth-of-July celebration is to make a cannon that will shoot life-sized dummies dressed in old clothes.  Building the cannon, as described in the following, makes it safe to fire and not dangerous to others, provided care is taken to place it at an angle of 45 deg. and not to fire when anyone is within its range.  The powder charge is in the safest form possible, as it is fired with a blow from a hammer instead of lighting a fuse.  If the cannon is made according to directions, there cannot possibly be any explosion.

The materials used in the construction of the catapult may be found in almost any junk pile, and the only work required, outside of what can be done at home, is to have a few threads cut on the pieces of pipe.  The fittings can be procured ready to attach, except for drilling a hole for the firing pin.

[Illustration:  Homemade Cannon Which will Hurl a Life-Size Dummy 100 Ft. through the Air]

Secure a piece of common gas pipe, 4 to 6 in. in diameter, the length being from 18 to 24 in.  Old pipe may be used if it is straight.  Have a machinist cut threads on the outside of one end, as shown in Fig. 1, and fit an iron cap, Fig. 2, tightly on the threaded end of the pipe.  The cap is drilled and tapped in the center for a 1-in. pipe.  Thread both ends of a 1-in. pipe that is 4 in. long, Fig. 3, and turn one end securely into the threaded hole of the cap.  This pipe should project 1/4 in. inside of the cap.  Fit a cap, Fig. 4, loosely on the other end of the 1-in. pipe.  A hole is drilled into the center of this small cap just large enough to receive a 6-penny wire nail, B, Fig. 4.

This completes the making of the cannon and the next step is to construct a dummy which can be dressed in old clothes.  Cut out two round blocks of wood from hard pine or oak that is about 3 in. thick, as shown in Fig. 5.  The diameter of these blocks should be about 1/8 in. less than the hole in the cannon, so they will slide easily.  In the center of each block bore a 1/4-in. hole.  Secure an iron rod, about 4 ft. long, and make a ring at one end and thread 4 in. of the other.  Slip one of the circular blocks on the rod and move it up toward the ring about 14 in.  Turn a nut on the threads, stopping it about 3-1/2 in. from the end of the rod.  Slip the other circular piece of wood on the rod and up against the nut, and turn on another nut to hold the wooden block firmly in its place at the end of the rod.  If the rod is flattened at the place where the upper block is located, it will hold tight.  These are shown in Fig. 5.  Take some iron wire about 1/8 in. in diameter and make a loop at the top of the rod for the head.  Wire this loop to the ring made in the rod and make the head about this loop by using canvas or gunny cloth sewed up forming a bag into which is stuffed either excelsior, paper