77. Fire
One of the most fundamental of human arts is the use of fire. It is also one of the most ancient. Its occurrence is easily traced, at any rate in deposits that have not been disturbed by nature, through the presence of charred bones, lumps of charcoal, and layers of ash. Charcoal crumbles easily, but its fragments are practically imperishable. Its presence in considerable quantities in any station, particularly if the coal is accumulated in pockets, is therefore sure proof that the people who occupied the site burned fires for warmth, or cooking, or both purposes. The use of fire has been established throughout the part of the Palæolithic when men lived in caves and under rock shelters; that is, during the Mousterian and Upper Palæolithic.
The Chellean and Acheulean deposits are so much older and more open, and in many cases have been washed over so much by rainfall and by streams, that, if the men of these periods did use fire, as they may well have done, its evidences might have been pretty generally obliterated.
Whether early Palæolithic men knew how to make fire, or whether they only found it and kept it alive, is more difficult to say. They could easily have acquired it in the first place from trees struck by lightning or from other occasional natural agencies. Then, recognizing its value, they may well have nursed it along, lighting one hearth from another. Yet at some time in the Palæolithic the art of producing fire at will, by friction between two pieces of wood, is almost certain to have been invented. One may infer this from the general similarity of level of Magdalenian civilization to that of modern savages, all of whom practise the art of ignition. But in the nature of things it would be difficult to find evidence bearing on this point from more than ten thousand years ago. It can be assumed that man is likely to have lived first for a long period in a condition in which he knew and used and preserved fire, yet was not able to produce it.