Fire were also kept going in the canoes when these were in use. There was little danger. Sea-water leaked through the seams and kept the interiors of the canoes perpetually damp. The fires were built on little heaps of sand and moist turf in the centre of the canoes. [...]
In the numberless sheltered nooks round the shores, at points where canoes could be safely beached, were Yaghan families living in their wigwams. If a distant sail appeared, or anything else occurred to startle those who had remained at home, they would send out a warning to those away fishing by piling green branches or shrubs on the wigwam fire. At the sight of the black signal smoke the fishers would hurry back home. The early explorers of that archipelago would see these countless columns of smoke rising at short intervals for miles along the coast. This is doubtless the reason why they named those regions Tierra del Fuego. It is possible, however, that some tract of grassland on the northern part of the island may have been seen burning."
Source: E. Lucas Bridge, Uttermost Part of the Earth - A History of Tierra del Fuego and the Fuegians
