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 is a measure of the flow of thermal energy from one object or substance to another. Thermal energy typically flows from a warmer material to a cooler material. Generally, when thermal energy is transferred to a material, the motion of its particles speeds up and its temperature increases. There are three methods of thermal energy transfer: conduction, convection, and radiation. Conduction transfers thermal energy through direct contact. If two objects are placed in contact with each other, thermal energy flows from the warmer object (with faster-moving particles) to the cooler object (with slower-moving particles).