In this appliance, a jet of mercury is forced out of a small aperture by means of a centrifugal pump, and is made to squirt against a metal plate, and interrupted intermittently by a toothed wheel made of insulating material rotated by the motor which drives the pump.
"Hertzian Wave Wireless Telegraphy"
John Ambrose Fleming
I have rotated them as scientifically as my ability permits.
"Epistles-from-Pap-Letters-from-the-man-known-as-The-Will-Rogers-of-Indiana"
Durham, Andrew Everett
The tubing is now rotated rapidly about its axis, and lowered so that the flame is just tangent to its lower side.
"Laboratory Manual of Glass-Blowing"
Francis C. Frary