Lamps - Firebrand

Primitive man was probably more concerned with fire as a source of warmth and as a means of cooking food than as a source of light. Before he discovered fewer laborious ways of making fire, he had to preserve it, and whenever he went on a journey he carried a firebrand with him. His discovery that the firebrand from which the torch may well have developed could be used for illumination was probably the incidental purpose of preserving a flame. Lamps, too probably developed by accident. Early man may have had his first conception of a lamp while watching a twig of fiber burning in the molten fat dropped from the roasting carcass. All he had to do was to fashion a vessel to contain fat and float a lighted reed in it. Such lamps, which were made of hollowed stones or seashells, have persisted in the identical form up to quite recent times. Which of the following statements can be derived from the text?