This is because Hg is an abbreviation of the Latin name of the element, which was hydrargium. With this name the Greeks were referring to the fact that mercury is a silvery liquid at room temperature, rather than a solid like other metals.
We've looked at the three types of heat transfer. Conduction and convection rely on temperature differences; radiation does, too, but with radiation the absolute temperature is important.
Heat transfer refers to the physical process by which heat energy moves from one area to another. The Heat Transfer Methods figure above illustrates various heat transfer methods. Branches above the fire are receiving heat by convection and radiation.