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"A current is caused to pass from the mercury through C along the radius of the disc A through the field of magnetic force due to the horse-shoe magnet NO. The result is that the wheel rotates in the direction indicated by the arrow." — Encyclopedia Britannica, 1893

Barlow Apparatus

"A current is caused to pass from the mercury through C along the radius of the disc A through the field…

The vision of the explorer Christopher Columbus.

The Vision of Columbus

The vision of the explorer Christopher Columbus.