seat by ropes attached to double rudders. This boat will
run at considerable speed and is very steady in rough water as it
goes directly through large waves instead of going over them.
--Contributed by Ernest Schoedsack, Council Bluffs, Iowa.

** How to Make a Lead Pencil Rheostat [145]

Take an ordinary lead pencil and cut seven notches at equal
intervals on the pencil down to and around the lead, leaving it
bare. A seven-point switch is constructed on a board of suitable
size making the points by using screws that will go through the
board. A small piece of tin or brass will do for a switch and is
fastened as shown. The connections are made on the back side of
the board as shown by the dotted lines. This will reduce 40 to 50
volts down to 5 or 10 volts for short lengths

[Illustration: Simple Rheostat]

of time.
--Contributed by Roy Newby, San Jose, Cal.

** Homemade Shoe Rack [146]

The accompanying sketch explains how a boy can make his own shoe
rack that can be placed on the wall in

[Illustration: Shoe Rack]

the clothes closet. Figure 1 shows the construction of the bottom
to permit the dirt to fall through. Two boards, 9 in. wide and
about 3 ft. long, with six partitions between, as shown, will make
pockets about 6 in. long. The width of the pockets at the bottom
is 2 in. and at the top 5 in.
--Contributed by Guy H. Harvey, Mill Valley, Cal.

** How to Waterproof Canvas [146]

The method used by the British navy yards for waterproofing and
painting canvas so it will not become stiff and cracked is as
follows: One ounce of yellow soap and 1/2 pt. of hot water are
mixed with every 7 lb. of paint to be used. The mixture is applied
to the canvas with a brush. This is allowed to dry for two days
and then a coat of the same paint, without the soap, is laid on.
When this last coat is dry the canvas may be painted any color
desired. After three days of drying the canvas may be folded up
without sticking together, and is, of course, waterproof. Canvas
waterproofed in this manner makes an excellent covering for
portable canoes and canvas boats. The color mixture for the soap
and second application is made from 1 lb. of lampblack and 6 lb.
of yellow ocher, both in oil; the finish coat may be any color
desired. When no paint is to be used on the canvas it may be
waterproofed with a mixture made from soft soap dissolved in hot
water, and a solution of iron sulphate added. Iron sulphate, or
ferrou