The scums forming on the top of the continuous defecator become so hard and dry that they have to be removed from time to time with a specially constructed instrument like a flat spade with three flat prongs in front.
Imagine now that a fork with black prongs is held near the cylinder with its prongs vertical and the plane of vibration parallel to.
In a common form of electrically maintained fork, the fork is set horizontal with its prongs in a vertical plane, and a small electro-magnet is fixed between them.
43 of the oppositely vibrating prongs of the fork.
Monte Santo), the most eastern of the three peninsular promontories which extend, like the prongs of a trident, southwards from the coast of Macedonia (European Turkey) into the Aegean Sea.