]
[Illustration: Paddling in the Old Scow.]
[Illustration: Fig. 51. The Trigger.]
[Illustration: Fig. 52. The Trigger Set for Firing.]
[Illustration: Fig. 53. The Umbrella Rib Crossbow.]
Megaphone.
[Illustration: Fig. 54. The Megaphone.]
[Illustration: Fig. 55. Layout of the Megaphone.]
[Illustration: Fig. 56 Brass Fastener.]
[Illustration: Fig. 57. The Mouthpiece.]
Another device we made in preparation for the expedition was a megaphone.
A sheet of light cardboard 30 inches square was procured. At the center of
one edge a pin was stuck into the cardboard, then a piece of stout thread
was looped over the pin and the two ends were knotted together just 5
inches from the pin. Another knot was a also made 29 inches from the pin.
Now, with a pencil hooked into the loop, and resting first against the
inner knot and then against the outer one, two arcs were drawn on the
paper, one of 5-inch radius and the other of 29-inch radius. A line was
now drawn from the pin to the point where the longer arc met the right
hand edge of the paper, and a dotted line was drawn from the pin to a
point 1-1/2 inches from the edge at the other end of the arc. From a point
1 inch to the left of the pin we then drew a line to the left end of the
arc.
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