ed over its
upper end. Near the-floor is a valve which is normally held closed by
a spring, and which has attached to it a foot operated lever. In
washing sediment out of jars, the case is inverted over the pipe, and
the water turned on by means of the foot lever. A number of fine,
sharp jets of water are thrown up into the jar, thereby washing out
the sediment thoroughly.

If an ordinary sink is used, a settling tank should be placed under
it, as shown in Figure 75. Otherwise, the drain pipe may become
stopped up with sediment washed out of the jars. Pipe B is removable,
which is convenient in cleaning out the tank. When the tank is to be
cleaned, lift pipe B up very carefully and let the water drain out
slowly. Then scoop out the sediment, rinse the tank with water, and
replace pipe B. In some places junk men will buy the sediment, or
"mud," as it is called.

[Fig. 75 Settling tank to be used with sink shown in Fig. 74]

Figures 76 and 77 give the working drawings for more elaborate wash
tanks. The water supply shown in Figure 74 may be used here, and the
drain pipe arrangement shown in Figure 75 may be used if desired.

[Fig. 76 Working drawing of a wash tank]

[Fig. 77 Working drawing of a wash tank]

LEAD BURNING (WELDING) OUTFIT

In joining the connectors and terminals to the positive and negative
posts, and in joining plate straps to form a "group," the parts are
joined or welded together, melting the surfaces to be joined, and then
melting in lead from sticks called "burning lead." The process of
joining these parts in this manner is known as "lead burning."
Directions for "lead burning" are given on page 210.

There are various devices by means of which the lead is melted during
the "lead burning" process. The most satisfactory of these use a hot,
pointed flame. Where such a flame is not obtainable, a hot carbon rod
is used.

The methods are given in the following list in the order of their
efficiency:

1. Oxygen and Acetylene Under Pressure in Separate Tanks. The gases
are sent through a mixing valve to the burning tip. These gases give
the hottest flame.

2. Oxygen and Hydrogen Under Pressure in Separate Tanks, Fig. 78. The
flame is a very hot one and is very nearly as satisfactory as the
oxygen and acetylene.

[Fig. 78]

Fig. 78. Hydrogen-Oxygen Lead Burning Outfit. A and B are Regulating
Valves. C is the Safety Flash Back Tank. D is the Mixing Valve. E is
the Burning Tip