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.
In short: the hotter you make your home and the colder it is outside, the more heat you're going to lose. To reduce that problem, you need to understand the three different ways in which heat can travel: called conduction, convection, and radiation. Sometimes you'll see these referred to as three forms of heat transfer. Conduction