"A copper wire coiled, by winding it around a piece of wood. The turns of the wire should be close together for actual experiment, they being parted in the figure to show the place of the iron to be magnetized. The best method is, to place the coiled wire, which is called the electrical helix, in a glass tube, the two ends of the wire, of course, projecting. Then placing the body to be magnetized within the folds, send the galvanic influence through the whole by placing the poles of the battery in the cups." —Comstock, 1850

Electrical Helix

"A copper wire coiled, by winding it around a piece of wood. The turns of the wire should be close together…