E.
It fits into a socket in the shaft of the forward wheels.

Figure 2 shows the construction of the cart below. The cog is
keyed or set-screwed to the driving shaft of the wheels with
either key or set-screw used in original fastening, as the case

[Illustration: Fig. 3, 4 Driving Shaft and Disk for Steering Gear]

may be. The chain is marked F, and there is a slot cut in the
floor of the cart to let the chain pass up and through to the cog
on the propelling shaft crank. The disk which receives the
steering rod is at G. The forward shaft bears only at the center
upon a disk of metal, consisting of any circular piece found among
the pieces of iron or brass at the junk store. One can get nearly
all the mechanical parts in junk establishments that purchase
parts of out-of-date or cast-away bicycles. The detail of the
driving shaft is shown at Fig. 3. The sprocket wheel is at H and
this is just as it is taken from the original bicycle shaft. The
bearings consist of wires looped around the shaft and inserted
into holes bored in metal plates as shown. These plates are
screwed to the bottom of the cart. The shaft itself is found in
rods or even cast-away metal axles which are commonly found in
most any carriage works, cycle shops or junk dealer's. Figure 4
shows the disk that receives the steering gear. The disk is bored
around edges for the securing screws, while the center is open for
the steering rod. When put together, three boys usually ride. One
steers and the other two turn the crank. Freight can be carried
and some boys do quite an express business in their town with one
of the carts like this that they made.

** Ringing a Bell by Touching a Gas Jet [403]

The experiment of scuffling the feet over a carpet and then
producing a spark which will light the gas by touching the
chandelier is described on another page. One of our correspondents
says that if a wire is connected to the chandelier and led to one
terminal of the coherer of a wireless telegraph outfit the bell
will ring every time the

[Illustration: Touch the Gas Jet and Ring the Bell]

spark is produced by touching the chandelier, and that, as the
chandeliers are all connected by the gas-pipe, the bell will ring,
no matter in which room the spark is produced.

** Lead Kills Knots [403]

The covering quality will be greatly improved if some dry red lead
is added to the shellac varnish used for killing knots.

** How to Make a Wood Tu