One great fundamental advantage that man has won over the other animals is that although by nature a diurnal animal he has made night almost equally subject to his dominion through the use of artificial light. He thus establishes an average day of sixteen or eighteen hours in place of the twelve-hour day within which his activities would otherwise be restricted. Of course this conquest of the night began at an early stage of the human development, since a certain familiarity with the uses of fire was attained long before man came out of the ages of savagery. But when the transition had been made from the primitive torch to the simplest type of lamp, there was for many centuries a cessation of progress in this direction, and it remained for comparatively recent generations to provide more efficient methods of lighting. Indeed, the culminating achievements are matters which make the most recent history. It is the purpose of the ensuing pages to narrate the story of the successive practical achievements through which man has been enabled virtually to turn night into day. PRIMITIVE TORCH AND OPEN LAMP To moderns, in an age when even the time-honored gas jets and kerosene lamps are regarded as obsolescent, that ancient form of illuminant, the candle, seems about the most primitive form of light-producing apparatus. In point of fact, however, the candle holds no such place in the chronological order of lighting-device discovery, being a relatively late innovation. Indeed, lamps of various kinds, even those burning petroleum, were used thousands of years before the relatively clean and effective candle was invented. The camp fires of primitive man must have suggested the use of a fire-brand for lighting purposes almost as soon as the discovery of fire itself; but the development of any means of lighting his caves or rude huts, even in the form of torches, was probably a slow process. For our earliest ancestors were not the nocturnal creatures their descendants became early in the history of civilization. To them the period of darkness was the time for sleeping, and their waking hours were those between dawn and dusk. It was only when man had reached a relatively high plane above the other members of the animal kingdom, therefore, that he would wish to prolong the daylight, and then the use of the torch made of some resinous wood would naturally suggest itself.