A small bottle of mercury is sent with each governor; also two small lead weights, which go on top of float B. The arrows show how the gas enters and leaves the governor.
Fig. 10.
Purifying the Metal.
The metal may be purified if, when in a molten state, a piece of green wood about 4 inches in diameter and 7 or 8 inches long, attached to an iron rod, is plunged into the molten metal and allowed to remain about 20 minutes, or until the boiling ceases.
The green wood causes the metal to boil violently, and the oxides contained in the interior of the molten metal are affectually reduced.
The metal should then be thoroughly stirred and the scum removed by an iron ladle.
The dross on the surface may be reduced by adding a few ounces of rosin to the molten mass.