On the top of this mixture a cast-iron perforated plate, weighing 95 lbs ... it was raised to a welding heat, and forged into four blooms under the steam hammer, then rolled into square billets ...

The power requirement for the heating element is significant — 13 amps — so the plate uses a solid state relay to turn things on and off. The iron has a ceramic bottom which is good for heat flow.

Cast iron is dense and retains heat for a long period ... meat defrost faster than if it was simply left on top of a dinner plate made of, say, glass, wood, or ceramic material.