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Popular Mechanics Co.

"The Boy Mechanic: Volume 1 700 Things for Boys to Do"


Next procure what is known as a wire connector. This is a piece of
copper tube about 1-1/2 in. long having two thumb screws, one on
each end on opposite sides (Fig. 2). The upper screw is to connect
the battery wire, the lower one to raise and lower the zinc. The
battery is now complete, and the solution (Fig. 1) must be
prepared. Proceed as follows:
In 32 oz. of water dissolve 4 oz. potassium bichromate. When the
bichromate has all dissolved, add slowly, stirring constantly, 4
oz. sulphuric acid. Do not add the acid too quickly or the heat
generated may break the vessel containing the solution. Then pour
the solution into the battery jar, until it is within 3 in. of the
top. Thread the wire holding the zinc through the porcelain
insulator of the carbon cylinder and also through the wire
connector. Pull the zinc up as far as it will go and tighten the
lower thumb screw so that it holds the wire secure. Place the
carbon in the jar. If the solution touches the zinc, some of it
should be poured out. To determine whether or not the zinc is
touched by the solution, take out the carbon and lower the zinc.


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