** How to Make a Lead Cannon [338]

Any boy who has a little mechanical ability can make a very reliable cannon for his Fourth-of-July celebration by following the instructions given here: 

[Illustration:  Lead Cannon Construction]

Take a stick—­a piece of curtain roller will do—­7 in. long.  Make a shoulder, as at A, Fig. 1, 4 in. from one end, making it as true and smooth as possible, as this is to be the muzzle of the cannon.  Make the spindle as in Fig. 1, 1/4 in. in diameter.  Procure a good quality of stiff paper, about 6 in. wide, and wrap it around the shoulder of the stick, letting it extend 3/4 in. beyond the end of the spindle, as at B, Fig. 2.  Push an ordinary shingle nail through the paper and into the extreme end of the spindle, as at A, Fig. 2.  This is to form the fuse hole.

Having finished this, place stick and all in a pail of sand, being careful not to get the sand in it, and letting the opening at the top extend a little above the surface of the sand.  Then fill the paper cylinder with melted lead and let cool.  Pull out the nail and stick, scrape off the paper and the cannon is ready for mounting, as in Fig. 3.  —­Contributed by Chas. S. Chapman, Lanesboro, Minn.

** Homemade Electric Bed Warmer [338]

The heat developed by a carbon-filament lamp is sufficiently high to allow its use as a heating element of, for instance, a bed warmer.  There are a number of other small heaters which can be easily made and for which lamps form very suitable heating elements, but the bed warmer is probably the best example.  All that is required is a tin covering, which can be made of an old can, about 3-1/2 in. in diameter.  The top is cut out and the edge filed smooth.  The lamp-socket end of the flexible cord is inserted in the can and the shade holder gripped over the opening.  A small lamp of about 5 cp. will do the heating.

A flannel bag, large enough to slip over the tin can and provided with a neck that can be drawn together by means of a cord, gives the heater a more finished appearance, as well as making it more pleasant to the touch.

** Making a Fire with the Aid of Ice [338]

Take a piece of very clear ice and melt it down into the hollow of your hands so as to form a large lens.  The illustration shows how this is done.  With the lens-shaped ice used in the same manner as a reading glass to

[Illustration:  Forming the Ice Lens]

direct the sun’s rays on paper or shavings you can start a fire.  —­Contributed by Arthur E. Joerin.

** How to Make a Crossbow and Arrow Sling [339]

In making of this crossbow it is best to use maple for the stock, but if this wood cannot be procured, good straight-grained pine will do.  The

[Illustration:  Details of the Bow-Gun and Arrow Sling]

material must be 1-1/2 in. thick, 6 in. wide and a trifle over 3 ft. long.  The bow is made from straight-grained oak, ash, or hickory, 5/8 in. thick, 1 in. wide and 3 ft. long.  A piece of oak, 3/8 in. thick, 1-1/2 in. wide and 6 ft. long, will be sufficient to make the trigger, spring and arrows.  A piece of tin, some nails and a good cord will complete the materials necessary to make the crossbow.