Note Footnote 8 — CHAPTER TEN
Reading edition
The "electrodes" are two 3/4'' pieces of platinum wire (#30), which are soldered to two pieces of insulated copper wire, each about 2 feet long.8 The other ends of the copper wire are bare. Fasten the bare end of one copper wire to one nail of the nail plug if you have direct current (d. c.) in the laboratory, and fasten the bare end of the other wire to the other nail; then turn on the electricity. If you do not have direct current in the laboratory, attach the copper wires to the two poles of a battery instead.