Isn't it amazing how the romans could heat rooms and baths far before electeric heaters were invented? The ingenius method of heating water in the roman baths was made possiple by the constant work of slaves. You see, slaves were constantly feeding a fire with wooden logs, that kept the fire going. The hot air created by the fire was transmitted through the coulumns, that held the floor of the baths up off the ground, and into the rooms. The hot air also travled through tunnels in the hollow walls of the bath, heating the room as well as the floor, for this reason, romans often wore shoes with very thick soles inorder to keep their feet from getting burned on the hot ground. Water also had to besuppliedto the baths. This water was pumped from hot underground springs, and broght to the baths through the 460 km. of aquaducts through out Rome. To heat this water, hot air from the basement was was seant up and around the bath