Henry, Joseph, 1797-1878 · Philadelphia, Printed by James Kay, Jun. & Brother · leaf 20
28 CONTRIBUTIONS TO ELECTRICITY AND MAGNETISM. „ . feet in diameter, and helix No. … they were quite severe. The effect, however, was still greater, when the helix was moved from the centre to the inner circumference, as at c: but when it was placed without the ring, in contact with the outer circumference, at b, the shocks were very slight; and when placed within, but its axis at…
Electromagnetic induction · Electromagnetism · Electric currents
Internet Archive · Smithsonian Libraries · Public domain (published before 1931). Free to use for anything.
![An illustration from [Graphophone patents] (1878)](https://img.insideoutlibrary.com/img/200/ia-graphophonepaten07unit-1033-658.webp)
