"Around a vertical conductor carrying a heavy current, place a peice of paper and sprinkle iron filling on the paper. Notice that the iron particles arrange themselves in distinct circular whirls around the wire, as shown." -Avery 1895

Magnetic Field Due to Current

"Around a vertical conductor carrying a heavy current, place a peice of paper and sprinkle iron filling…

"Coil some No. 12 copper wire throuh holes in a board, as shown, and pass a strong current through it. Sprinkle iron filling as before and note the effect. Such a coil of conducting wire, wound so as to afford a number of equal and parallel circular electric circuits arranged upon a common axis, is called a solenoid." -Avery 1895

Solenoid

"Coil some No. 12 copper wire throuh holes in a board, as shown, and pass a strong current through it.…