The Boy Mechanic Part 53

In general, a drop in the mercury indicates a storm and bad weather, while a rise indicates fair weather and in winter a frost. Sudden changes in the barometer are followed by like changes in weather. The slow rise of the mercury predicts fair weather, and a slow fall, the contrary. During the frosty days the drop of the mercury is followed by a thaw and a rise indicates snow.

** Home-Made Post or Swinging Light [189]

Remove the bottom from a round bottle of sufficient size to admit a wax or tallow candle. This can be done with a gla.s.s cutter or a hot ring; the size of the outside of the bottle, which is slipped quickly over the end. Procure a metal can cover, a cover from a baking powder can will do, a lid fit it on the end where the bottom was removed. The cover is punched full of holes to admit the air and a cross cut in the center with the four wings thus made by the cutting turned up to form a place to insert the candle. The metal cover is fastened to the bottle with wires as shown in the sketch. This light can be used on a post or hung from a metal support.

[Ill.u.s.tration: Swinging Light]

** A Checker Puzzle [189]

Cut a block from a board about 3 in. wide and 10 in. long.

Sandpaper all the surfaces and round the edges slightly. Mark out seven 1-in. squares on the surface to be used for the top and color the squares alternately white and black. Make six men by sawing a curtain roller into pieces about 3/8 in. thick. Number the pieces 1, 2, 3, 5, 6 and 7, and place them as shown in Fig. 1.

The puzzle is to make the first three change places with the last three and

[Ill.u.s.tration: Position of the Men]

move only one at a time. This may be done as follows:

Move 1-Move No. 3 to the center.

Move 2-Jump No. 5 over No. 3.

Move 3-Move No. 6 to No. 5's place.

Move 4-Jump No, 3 over No. 6.

Move 5-Jump No. 2 over No. 5.

Move 6-Move No. 1 to No. 2's place.

Move 7-Jump No. 5 over No. 1.

Move 8-Jump No. 6 over No. 2.

Move 9-Jump No. 7 over No. 3.

Move 10-Move No. 3 into No. 7's place.

Move ll-Jump No. 2 over No. 7.

Move 12-Jump No, l over No. 6.

Move 13-Move No. 6 into No. 2's place.

Move 14-Jump No. 7 over No. 1.

Move 15-Move No. 1 into No, 5's place.

After the 15 moves are made the men will have changed places. This can be done on a checker board, as shown in Fig. 2, using checkers for men, but be sure you so situate the men that they will occupy a row containing only 7 s.p.a.ces.

--Contributed by W. L. Woolson, Cape May Point, N.J.

** Gold Railroad Signals [189]

Covering railroad signals with gold leaf has taken the place of painting on some roads. Gold leaf will stand the wear of the weather for 15 or 20 years, while paint requires recovering three or four times a year.

** How to Make a Bell Tent [190]

A bell tent is easily made and is nice for lawns, as well as for a boy's camping outfit. The ill.u.s.trations show a plan of a tent 14-ft. in diameter. To make such a tent, procure unbleached tent duck, which is the very best material for the purpose, says the Cleveland Plain Dealer. Make 22 sections, shaped like Fig. 3, each 10 ft. 6 in. long and 2 ft. 2 in. wide at the bottom, tapering in a straight line to a point at the top. These dimensions allow for the laid or lapped seams, which should be

[Ill.u.s.tration: An Inexpensive Home-Made Tent]

double-st.i.tched on a machine. The last seam sew only for a distance of 4 ft. from the top, leaving the rest for an opening.

At the end of this seam st.i.tch on an extra gusset piece so that it will not rip. Fold back the edges of the opening and the bottom edge of the bell-shaped cover and bind it with wide webbing, 3 in.

across and having eyelets at the seams for attaching the stay ropes. Near the apex of the cover cut three triangular holes 8 in.

long and 4 in. wide at the bottom and hem the edges. These are ventilators. Make the tent wall of the same kind of cloth 2 ft. 2 in. high. Bind it at the upper edge with webbing and at the bottom with canvas. Also st.i.tch on coa.r.s.e canvas 6 in. wide at the bottom, and the s.p.a.ce between the ground and the wall when the tent is raised, fill with canvas edging. St.i.tch the upper edge of the wall firmly to the bell cover at the point indicated by the dotted line, Fig. 2.

For the top of the tent have the blacksmith make a hoop of 1/4-in.

round galvanized iron, 6-in. diameter. St.i.tch the canvas at the apex around the hoop and along the sides. Make the apex into a hood and line it with stiff canvas. Have the tent pole 3 in. in diameter, made in two sections, with a socket joint and rounded at the top to fit into the apex of the tent.

In raising the tent, fasten down the wall by means of loops of stout line fastened to its lower edge and small pegs driven through them into the ground, Fig. 5. Run the stay ropes from the eyelets in the circular cover to stakes (Fig. 5) stuck in the ground. Use blocks, as in Fig. 6, on the stay ropes for holding the ends and adjusting the length of the ropes.

** Simple X-Ray Experiment [190]

The outlines of the bones of the hand may be seen by holding a piece of rice paper before the eyes and placing the spare hand about 12 in. back of the rice paper and before a bright light. The bony structure will be clearly distinguishable.

--Contributed by G.J. Tress, Emsworth, Pa.

** How to Make a Candle Shade [191]

Layout the pattern for the shade on a thin piece of paper, 9 by 12 in., making the arcs of the circle with a pencil compa.s.s. As shown in the sketch, the pattern for this particular shade covers a half circle with 2-3/4 in. added. Allowance must be made for the lap and as 1/4 in. will do, a line is drawn parallel 1/4 in. from the one drawn through the center to the outside circle that terminates the design.

Nail a thin sheet of bra.s.s, about 9 in. wide by 12 in. long, to a smooth board of soft wood, then trace the design on the bra.s.s by laying a piece of carbon paper between the pattern and the bra.s.s.

After transferring the design to the bra.s.s, use a small awl to punch the holes in the bra.s.s along the outlines of the figures traced. Punch holes in the bra.s.s in the s.p.a.ces around the outlined figures, excepting the 1/4-in. around the outside of the pattern.

When all the holes are punched, remove the bra.s.s sheet from the board and cut it along the outer lines as traced from the pattern, then bend the bra.s.s carefully so as not to crease the figures appearing in relief. When the edges are brought together by bending, fasten them with bra.s.s-headed nails or brads.

If a wood-turning lathe is at hand, the shade can be made better by turning a cone from soft wood that will fit the sheet-bra.s.s shade after it is shaped and the edges fastened together. The pattern is traced as before, but before punching the holes, cut out the bra.s.s on the outside lines, bend into shape, fasten the ends together and place on the wood cone. The holes are now punched on the outlines traced from the pattern and the open s.p.a.ces made full of holes. The holes being punched after the shade is shaped, the metal will stay and hold the perfect shape of a cone much better.

The gla.s.s-beaded fringe is attached on the inside of the bottom part with small bra.s.s rivets or brads placed about 3/4 in. apart.

The thin sheet bra.s.s may be procured from the local hardware

[Ill.u.s.tration: Punching the Holes; Completed Shade; Pattern]

dealer and sometimes can be purchased from general merchandise stores.

--Contributed by Miss Kathryn E. Corr, Chicago.

** A Putty Grinder [191]

Having a large number of windows to putty each week, I found it quite a task to prepare the putty. I facilitated the work by using an ordinary meat cutter or sausage grinder. The grinder will soften set putty and will quickly prepare cold putty. It will not, however, grind old putty or make putty from whiting and oil.

--Contributed by H. G. Stevens; Dunham, Que.