Fire

FIRE is so familiar that it scarcely needs definition. Its extraor dinary usefulness and equally extraordinary dangers impress practically every human being from infancy onward. Ordinary fire is the rapid chemical combination of oxygen with the carbon and other elements of organic substances in such a way that heat, flame and light are produced. In a broader sense fire is the process whereby the combination of one chemical element with another, when reduced to a gaseous condition, produces heat and flame.

Among all the discoveries and inventions made by men, only a few, such as speech, writing and agriculture, have borne such momentous fruit as has the discovery of how to make and use the type of combustion commonly known as fire. The use of fire is the basis of practically all forms of modern manufacturing and transportation; it has been a powerful agent in determining the spread and present distribution of mankind and of civilization; it has perhaps been a major, although indirect agent in causing racial differences in mentality. It is the background and basis of our modern industrial life.

Universality of Fire.

Traces of fire appear among the earli est human relics, far back at the beginning of Paleolithic times. During historic times it is doubtful whether any race or tribe has ever been completely without knowledge of fire. Early travellers, to be sure, have brought back tales like that of the missionary Krapf in East Africa. He heard from a slave that a tribe in southern Shoa lived like monkeys in the bamboo jungles and were totally ignorant of fire. That was in the middle of the i 9th cen tury, but no competent observer has yet seen such a tribe. In the same way Wilkes of the famous United States Exploring Expedi tion in the Pacific reported that no sign of places for cooking, nor any appearance of fire was found in Bowditch Island (Fakaafo), but Hale, the ethnographer of the same expedition, reports the native word for fire. We now know that these people not only talked about fire, but have a legend as to its origin and could kindle a blaze. Since other reports of fireless people fare in the same way, Sumner and Keller seem justified in saying that "it is certain that over the whole earth no fireless tribe of men has been found. . . . Man is scarcely man till he is in possession of fire." Original Use of Fire.—Although we have no real knowledge as to the original use of fire or as to man's discovery of the art of kindling a flame, primitive legends, the usages of primitive people and ancient religious ceremonials give some clue to the major facts. One of the most important conclusions derived in this way is that fire was used long before it could be artificially generated. Lippert even goes so far as to argue that the use of fire enabled man's ape-like progenitor to descend from the trees and walk erect because it gave him protection from other animals. Even if this idea is untenable, as it probably is, one of man's earliest discoveries must have been that he could make profitable use of the fires engendered naturally by lightning, falling meteors, the materials ejected from volcanoes, friction developed by ava lanches and boulders and other natural occurrences. He probably soon realized the value of a blaze not only for warmth, but for cooking food, warding off wild beasts and driving game out of the jungle. Thus early man presumably cherished fire long before he learned how to make it.

Preservation of Fire.

Even in modern times many tribes have been observed which carefully preserve their fire year after year and suffer serious loss if it is extinguished. The people of the Andaman islands, who are said to be ignorant of the art of pro ducing fire, take a smouldering stick with them and keep it burn ing if they go away from their huts for more than a few hours on a hunting or fishing expedition. Among certain Papuans who have no means of kindling a blaze, live coals of a very slow-burning wood are constantly preserved in the huts. If by chance the fire goes out, these coast dwellers have to go to the mountains where the inhabitants understand the art of fire-making, and bring thence some live coals. Even where the art of kindling a fire is understood, the technique is often so crude or the difficulties because of damp weather are so great that the fire is preserved with extraordinary care. The Australian aborigines prefer to make long journeys to get fire from another tribe rather than undertake the labour of making it themselves. Among the Herero, to cite one of the many examples given by Sumner and Keller, the diffi culty of making fire by friction was formerly so great that the daughters of the household were regularly charged with the care of the flame. If the fire went out, it was regarded as an evil omen.

Fire and Religious Rites.

A great number of facts of this kind agree with some of the most widespread and primitive legends and religious practices. According to the familiar Greek legend, Prometheus brought fire to earth. Sometimes he is said to have lighted a torch at the sun's chariot, and sometimes to have gone underground. In the Cook islands near New Zealand, the Poly nesian hero Maui is said to have obtained fire for man by going down to hell where he learned to generate a spark by rubbing two pieces of wood together. Perhaps the multitudinous legends of this sort are reminiscent of the period when the art of making fire was unknown. In such circumstances there must have been repeated periods when prolonged rainy spells or other accidents put out all the fires among the very scanty population of a large area. In such a case no fire may have been available for many years, and the bringer of new fire would be a hero. Perhaps a late relic of the periodic loss of fire is found in certain ceremonies of both the Roman Catholic and Greek Orthodox churches. Accord ing to the traditional method, all the lights in the churches are gradually extinguished during Passion Week. When the last light has been extinguished, "new fire" is made ; formerly this was done by some primitive means, such as friction of wood, long after flint and steel were understood. From this "new fire" all the lights to be used throughout the next year are supposed to be kindled. At Jerusalem the rush of the Eastern Orthodox pilgrims to light their candles at the newly created blaze has often made it necessary to employ soldiers to preserve order. Another reminiscence of the early necessity for extreme care in preserving fire is found in the Vestal Virgins who tended the undying fire in Rome. Elsewhere, as in ancient Peru, a similar custom is reported.

Worship and ceremonies connected with fire play at least a subordinate part in almost every religion, they sometimes become dominant. In the ancient Jewish religion and many others fire is the means whereby offerings are transmitted to the deity or to departed souls as among the Greeks. In many cases fire itself is worshipped, and often the worship of the sun can scarcely be distinguished from that of fire. The ancient Mexi cans had a fire-god Xiuheuctli, closely related to the sun-god; the Kamchadals and Ainus of north-eastern Asia make fire their chief deity. Among more civilized people the ancient Assyrians, Chal daeans and Phoenicians practised fire-worship; Abraham was perhaps a reformer who refused to sacrifice his son Isaac in the consuming fire ; the Israelites of later times were often scourged by their prophets for offering their children as sacrifices to Moloch, the god of fire. Among the ancient Aryans, if we may use so indefinite a term, Agni (Latin ignis) was the chief god. Even to-day fire-worship is a notable feature of Hinduism, which is an offshoot of the old Aryan cult, and is the dominant factor in the religion of the Zoroastrians or Parsees. Among the oppressed rem nant of the Parsees who still survive in the parts of Persia near Yezd and Kirman, and among many more primitive people, it is considered most irreverent to throw into the fire anything impure or disagreeable or to spit into it. The modern Parsees do indeed regard fire as merely a symbol, but in the beginning fire itself was probably the real object of worship. This is not surprising for there is probably no agency more powerful for good and ill, and motives of both gratitude and fear must have mingled in the minds of the early worshippers.

Although the worship of fire has largely disappeared in our day, its symbolism is still widely spread. The fire of love, the fire of ambition, are common similes.

Discovery of the Art of Fire Making.—In many of the legends which centre around the origin of fire, the interesting figure of the serpent-fighter occurs. The native Australians of Victoria say that a certain Karakorok, the good daughter of the good old man Pundyil, went abroad to kill the serpents which filled the land. Before she had killed them all, her staff snapped and a flame burst out of it. According to the ancient Shahnama of Persia, a hero called Hushenk hurled a prodigious stone at a snake ; the snake escaped, but the stone struck a rock whereupon "light shone from the dark pebble, the heart of the rock flashed out in glory, and fire was seen for the first time in the world." A North American legend states that the buffalo gave fire to man ; as he raced in great herds across the plains at night, he lighted up the darkness with sparks and set the brush ablaze as his hoofs hit the rocks. The Dakota Indians replace the buffalo by a friendly panther which struck fire from its claws as it scampered up a stone hill. In South America the Quiches claim to have received fire from Tohil who produced it by shaking his sandals. His sign, like that of the Mexican god, Quetzalcoatl, is a flint. The vital point in all these legends is that the movements of men or animals cause stones to crash together, thus producing a spark which gives rise to fire. Such occurrences, together with his own experience in breaking rocks in order to discover which make the ' best tools, may have led some savage genius to discover that when flint and iron pyrites are struck together they produce sparks which will ignite dry grass or leaves. That mode of making fire is especially likely to originate in regions where rocks and dry grass are abundant.

In moist regions where the soil is so deep and the vegetation so dense that rocks are rare, or in places where flinty rocks are not present, another kind of natural occurrence is more likely to have helped in the discovery of fire. Now and again in the dry season two dead branches, rubbing together in the wind, become so hot that they ignite. Such accidents are not common, but during the hundreds of thousands of years of man's early development they presumably occurred often enough to be observed by men who possessed not only the ability and vision to see their significance, but also the curiosity and energy to make experiments.

Methods of Making Fire.—These two methods, percussion and friction, have always been the chief ways of making fire, but concentration of the sun's rays and the electric spark have also come into use. Friction has been by far the most widespread method among primitive people. In one of the simplest frictional methods the blunt end of a stick is rubbed back and forth along another piece of wood lying on the ground. The stick makes for itself a groove, and ultimately a spark is developed. This method formerly prevailed among the savages in New Zealand, Hawaii, Tonga, Samoa and elsewhere. In Tahiti Charles Darwin saw a native produce fire thus in a few seconds, but he himself succeeded only after long effort. In a somewhat more advanced frictional method the movable stick is rotated as rapidly as possible in a stationary piece of wood that lies on the ground. Such a fire drill, as it is commonly called, is sometimes rotated by rubbing the ver tical stick between the palms of the hands. This device in one form or another has been observed among the primitive people in Australia, Kamchatka, Sumatra and the Caroline islands. It is common among the Veddahs of Ceylon and in much of southern Africa as well as in large parts of both Americas. Various improve ments have been devised in order to increase the speed of rotation. On the Pampas of South America the Gaucho formerly took an elastic stick about i8in. long, placed one end in a hole in a sta tionary piece of wood, pressed the other to his breast, leaned down to bend the stick, and then rapidly turned the curved part like a carpenter's bit. A better method is to wind a string around the rotating stick or drill and pull it back and forth. In order to make it possible for one man to do this effectively, the Eskimos place the upper end of the drill in a socket of ivory or bone which can be held firmly in the teeth. Other Eskimos, as well as some Indians, fasten the two ends of the string to a bow and saw the bow back and forth. In our own day a device of this kind, with sawdust or some such material in the bottom of the hole to make the sparks catch quickly, is one of the first things taught to boy scouts. Still more ingenious than the bow drill is the pump drill of the Onan daga Indians. Here a string is fastened in such a way that when a small board is repeatedly pushed down the drill stick twirls rap idly, first one way and then the other. Many modifications of these methods are described and illustrated in the works of Tylor and Pauschmann.

In all the simpler frictional methods the two great difficulties have always been to create a spark and then to bring it into imme diate contact with a sufficient amount of easily combustible tinder. In the most modern method—the match—both of these were first obviated by coating the ends of the movable stick with sulphur, which ignited at low temperature, and tipping the end with phos phorus which can be still more easily ignited by a single stroke. By the substitution of potash and non-poisonous forms of phos phorus for the earlier ingredients the modern safety match has at last been evolved as the latest successor of the two sticks rubbed together.

The method of making fire by percussion does not appear to have been of great importance until the Iron Age was so far advanced that steel was available. Its development was delayed by the difficulty in finding natural products such as pyrites which can be relied on to produce a spark when struck with a flint. After iron became common, the flint and steel became the best method of creating a fire. This method, however, was dominant for only a short time compared with the frictional method, for as soon as matches tipped with sulphur and phosphorus came into use (soon after 1830), it ceased to be of importance except in more backward regions. There it survives widely; in Central Asia flint-lock guns are still common.

Another method of making fire, namely, the concentration of the sun's rays by means of a lens or mirror, also belongs to a fairly high stage of civilization, but has never been used to any great extent. Aristophanes mentions a burning-lens in The Clouds; although the mirrors of Archimedes may not actually have set fire to the ships of the Roman besiegers of Syracuse, they show that the art of generating fire in this way was well understood. In Peru the sacred fire is said to have been kindled by means of a concave cup set in a great bracelet. In China the burning-glass has long been well known.

The latest important method of making fire is by means of the electric spark. According to one common device, a gas jet is arranged so that when it is opened an electric circuit is closed and then broken, and a spark passes through the escaping gas and ignites it. It should be noted in this connection that the intense heat generated by the electric current is beginning to displace fire not only in cases where an extremely high temperature is desired, but in various household appliances and elsewhere. This is only a partial displacement, however, for in most cases the electric current itself is generated by means of a fire in which coal is burned.

Fire and Material Progress.

When once the art of using and making fire became established, it must have altered human devel opment in at least three ways. First, it must have stimulated the inventive faculty, thereby leading to material progress ; second, it must have led to an increase in the density of population; third, it must have enabled primitive man to inhabit areas which had previously been too cold. These three changes must have had a profound effect upon the location of the centres of civilization and progress, and perhaps upon the mental development of the various human races.

One invention commonly leads to another. Fire must have been peculiarly important in this respect. Although no exact knowledge is possible, we can infer with considerable certainty that after people once mastered what was then the extremely difficult art of using fire, it required only a moderate degree of inventiveness to make many other important discoveries. The primitive fire-users must soon have learned that sticks which are partly burned in the fire become pointed and hardened, thereby becoming more serv iceable as weapons. Even if the effect of fire on food was not previously known, bits of flesh, green fruit, edible roots or other kinds of food must inevitably have fallen accidentally into the fire and been cooked as soon as fires became common. Their improved flavour and tenderness when rescued must have led persons with the keener type of mind to make experiments. The range of opportunities thus opened is enormous, for practically every grow ing thing which had the least semblance of edibility must have been subjected to the process of roasting. As time went on, and it became possible to. heat water in skin bags by means of hot stones or in earthen vessels, the art of boiling food must have been dis covered. At some time or other an earthenware jar which boiled dry, or some other accident must have suggested the possibilities of baking food by enclosing it within non-combustible receptacles. In our own day experiments in the use of fire for cooking are perhaps more numerous and vigorous than ever before.

Food is only one of the ways wherein fire obviously stimulated experiments. During the long period when the use of fire was known but the art of generating it unknown, the desire to create a blaze must have stimulated men's inventive faculties even more persistently than we are now stimulated by the desire to secure new and better sources of power. Again, having seen that animals are so averse to a blaze, he must have asked himself : "How can I best use fire to keep away animals during the night?" Then he presumably found that a flaming torch is a most effective weapon when thrust into the face of a wild animal. Thus the stimulus to invention must have gone on so that men discovered that fire brands hurled into the huts of their enemies are a good weapon, or that when a patch of jungle is burned, the wild animals can be driven out and easily caught. In later days when civilization had advanced far higher, similar reasoning and experiment showed that flaming pitch, red hot balls of metal or explosive projectiles are effective ways of lighting fires in the midst of the enemy.

In connection with metallic ores fire has been a main agency in stimulating the inventive faculty. The first inkling as to the pos sibility of smelting presumably arose from the accidental melting of bits of ore in a hot fire. When once the significance of that fact was grasped by some genius, and when the highly valuable qualities of the resultant metals were realized, the stimulus toward melting all sorts of stones must have been enormous. Here, too, we see a line of experiments which has continued with in creasing intensity to our own day. Thousands upon thousands of skilled inventors have worked upon the problem of making hotter and hotter fires. Thus we have melted more and more refractory stones, thereby enormously increasing the number of available metals and other valuable compounds. In this respect, as in many others, fire and its possibilities are still among the greatest agencies in stimulating human progress.

Greater perhaps than any of the preceding—or at least later and more striking in its effect—is the relation of fire to power. As soon as the first savage saw a yam or other bit of vegetation pop in the fire because steam was escaping, the principle of the development of power from fire was brought to man's attention. For hundreds of thousands of years thereafter many a boy pre sumably experimented by holding the lid down over a boiling ves sel of water until the steam puffed it violently up. Many a man in addition to Hero, who made what was really a steam engine more than 2,00o years ago, must have realized that the expansive force of steam possesses energy which might be of high value. But only in modern times did progress along other lines finally make the steam engine a practical invention. Then the attempt to use the energy liberated by fire suddenly gave an almost incredible stimu lus to the world's inventive faculties. Our whole modern system of manufacturing, transportation, lighting and heating is based on the utilization of fire.

Pyrotherapy and Sterilization.

One of the most extraor dinary features of fire is the way in which its use continues to increase even in our own day. This is especially true in the field of health. The value of cauterization in preventing harm from poisonous bites like those of snakes or mad dogs, and in preventing the spread of infection from wounds or sores has long been known, and was practised by the ancients. The value of hot baths in skin disease and in those of the joints has also been appreciated, at least since the days of the Romans. Only in modern times, how ever, have two other therapeutic uses of fire become known. One is the process of baking whereby a limb or other member is kept for a while at a temperature as high as it can endure with re sults which are said to be highly beneficial. The other is the use of fire for sterilization. The knowledge that heat, either in the form of flame or through the medium of steam or hot water, will kill bacteria has been one of the most revolutionary discoveries of modern times. To it, perhaps, as much as to any other single factor, is due the wonderful progress of modern surgery.

Dangers of Fire.—In spite of all the benefits derived from fire, the mere word "Fire !" is one of the most dreaded expressions in every language, for fire is as dangerous as it is useful. Some of the greatest disasters in all history have been fires such as those in Rome in the time of Nero, and the one which ravaged London for four days in i666 and gave Sir Christopher Wren a chance to plan many important improvements. Chicago suffered a similar fire in 1871 and i 00,00o people were rendered homeless; San Francisco experienced a similar fate after the great earthquake of 1906. Earthquakes have been the cause of some of the most terrible fires, as in Tokyo in 1923. There the style of architecture renders fires especially dangerous, for the houses are constructed of wood with paper walls and heavy thatch of straw. At Tokyo the fire killed 60,0oo or 70,000 people, burned 25 sq.m. and drove away nearly 1,000,000 persons. In all countries the annual losses by fire are enormous. In England they amount to about L12,000,000 annually. In the United States, partly because wooden houses are more common than in Europe, the losses are far greater, amounting to over half a billion dollars every year from 1922 onward, and to $560,000,000 in 1926, or approximately $5 per person. In that same year the fear of fire led the people of the United States to pay $635,000,000 in premiums to fire in surance companies, while $352,000,000 was returned to cover losses. Forest fires are amazingly frequent and some of them lay waste thousands of square miles. From 1916 to 1925 the average number of such fires in the United States alone was about 51,000. Nearly half of these devastated at least ten acres ; the average damage to trees and property amounted to about $21,000,000, but the real damage was enormously greater because the fires kill the young growth, expose the soil to erosion, and alter the char acter and density of the new growth. In 1825 one of the greatest forest fires burned an area of 3,000,000ac. in Maine and New Brunswick, while fires that burned more than 1,000,000ac. in the United States and Canada occurred in 1853, 1871 (two totalling 3, 28o,000ac. ), 1881 and 1910. Such fires may still occur in re gions like Siberia, but are impossible in the more advanced countries because of the improved methods of fire-protection. • The Effect of Fire on Density of Population.—One of the most noteworthy facts in the history of civilization is the way in which many of the greatest inventions increase the density of population. Inventions connected with fire are pre-eminent in this respect. One of the first effects of the original discovery of the art of using fire must have been to increase the available food supply. It did this directly through the art of cooking, whereby many previously inedible or indigestible products became good articles of diet, and also by making it possible to smoke and pre serve food that otherwise would have been wasted. Indirectly the use of fire still further increased the food supply by improving man's tools. It not only enabled him to use sharpened sticks as described above, but helped him to break up the stones from which he procured flint implements, and kept him warm and dry so that he could work more effectively in cool weather. It enabled him to smelt metals and ultimately to make machines of all sorts. Thus fire has been a major agent in the process whereby man has multiplied his labour so that one man with the help of fire-made and fire-driven machinery can do as much work as scores or hun dreds who have only their naked hands and no help from fire. In recent centuries no factor has exceeded the use of coal in f os tering the growth and concentration of population; in earlier times the use of fire in other ways produced similar although less obvious results.

Fire and the Coldward March of Civilization.—One of the most extraordinary results of the use of fire is the way in which it has enabled the centres of human progress to move from warmer to cooler regions. According to the most recent studies the best climate for primitive savages without fire, clothing or shelter, is one where the temperature averages not far from 7o° at all seasons, but yet has a fair degree of variability. The nearest approach to such a climate is by no means found in equatorial regions but at a distance of 25° or more to the north or south. Even there, however, although the winters are admirable, the sum mers are much too long and warm for the best health and greatest efficiency. Now man is so constituted that up to a certain point he can endure too much heat more easily than too little. Among naked savages, for example, a temperature of 9o° is far less un comfortable than one of 6o°. Therefore unless people possess artificial means of warming themselves they tend to live in re gions that are too warm rather than too cold. This retards prog ress, for people usually overcome the adverse effect of high tem perature by inactivity rather than activity.

The introduction of fire changed all this. In conjunction with discoveries as to clothing and shelter, it enabled people to be com fortable in cool climates. Each new discovery meant a step away from low latitudes. The invention of the hearth to replace the bare ground as a place for a fire was one of the earliest reasons for such a step. The invention of a protected opening in the roof to carry off the smoke was another. Still another was the com bination of the hearth with a chimney in such a way as to give an efficient draft, eliminate smoke and throw the heat out into the room ; then came the enclosed oven or stove of mud as in China; later the stove of metal; then central heating by means of fur naces supplying hot air, steam or hot water and heated first by wood, then by coal, and lately by oil or gas. Each of these im provements in the use of fire, together with the corresponding advances in clothing and architecture, reduced the difficulties due to low temperature, for they helped to create an artificial climate in which people were approximately as comfortable, healthful and energetic as in the ideal climate. Thus to-day we can live com fortably and in good health in climates so cold that people without fire would perish.

One of the greatest benefits of man's conquest of fire has been that the human race has gradually been able to migrate into the cooler and hence more healthful and energizing parts of the world. At every stage of this process of expansion there has been a definite zone of highest comfort, best health and greatest activity. Beginning not far beyond the tropics, the zone shifted to Mediter ranean lands, and then to higher latitudes. To-day it is coinci dent with the zone of greatest progress, highest civilization and world dominance, a condition which also appears to have been true in the past. A further advance in the use of fire may pos sibly carry the zone of greatest progress as far north as southern Scandinavia and southern Canada, but not beyond, for there the summers as well as the winters become too cool. The ultimate location of this most favoured zone will doubtless be the regions where the following three conditions are most nearly fulfilled: (I) the summer climate is ideal for civilized people who wear clothes and live in houses; (2) the use of fire creates ideal atmos pheric conditions within doors during the rest of the year; and (3) the degree of variability arising from the weather on the one hand and the use of fire on the other produces the maximum stimulus, but does not injure health. With our present skill in the use of fire a climate like that of London comes as near as any to satisfy ing these three conditions, but the regions surrounding Paris, Ber lin, New York and Chicago do not lag far behind.

From all this it appears that the "coldward course of progress" as GilFillan has called it, or the "northward course of empire" to use Stefansson's phrase, has depended upon the use of fire more fully than on any other factor that is yet clearly defined. It has involved a migration of the centres of power from regions where the winter climate is ideal but the summers debilitating, to those where the summer climate is ideal, and the disadvantages of the winter can be obviated by the use of fire together with clothing and shelter.

Fire and Racial Inheritance.—The possible biological effect of fire upon mankind ought not to be overlooked, although it is highly speculative. At first, and perhaps for many generations, the users of fire probably comprised only a small group of un usually intelligent, competent and progressive people. The first persons to use almost any revolutionary discovery are usually of that sort, no matter whether the discovery be the aeroplane, the electric motor, the art of weaving or the alphabet. During the long period when the technique of fire was new and crude its users must have had great need of intelligence, skill, patience and material prosperity, for otherwise they would not and could not have devoted to the art the many hours each day that must inevitably have been required. Among primitive hunters who are constantly obliged to change their abode it is by no means easy to maintain a fire that must never be allowed to go out, and the new arts of cooking and drying food and making fire-hardened weapons must also have been difficult. But the people who were sufficiently wise, active and patient to master all these difficulties must have reaped great advantages. Their food supply, as we have seen, became more abundant, more reliable and more nu tritious, their improved weapons lessened the danger from both beasts and men, and their children must have enjoyed a freedom from hunger, exposure, disease and danger hitherto unknown. Such advantages, in a day when there was no such thing as birth control, must have caused the descendants of the fire-users to increase in number faster than did the people who lacked the wit, energy or resource to use the new invention. Thus, if there is any truth in the inheritance of mental traits, the inherent intel ligence and progressiveness of the population must have been improved.

The degree of improvement must have differed from place to place. Near the equator the people presumably made little use of fire ; the warmth of their climate not only prevented them from feeling much need of it, but made them loathe the necessary exer tion. Thus in such regions fire had little effect in causing the intelligent people to increase in numbers. In the cooler parts of man's primitive habitat, on the contrary, the use of fire presum ably caused the descendants of the more intelligent and progres sive people to be numerous in proportion to those of the more stupid and indifferent, thus altering the average level of innate in telligence. Beyond the limits of the old inhabited area the use of fire enabled people to migrate into regions previously too cold for occupancy. Since all the migrants must have been of the intelli gent fire-using class, whatever innate superiority they may have possessed must have been segregated and thereby perpetuated. Thus there must have been a gradation of innate ability from the unaltered people of the hottest regions to the selected new settlers in cooler regions. If such a differentiation occurred once, it must have occurred repeatedly when further progress in the mastery of fire enabled mankind to move into still cooler regions. The result would correspond exactly with the temperamental differences which now seem to be innate in the people of tropical as compared with temperate regions. All this is indeed speculative, but it ought not to be overlooked in considering the part played by fire in the development of mankind.

BIBLIOGRAPHY.-E.

B. Tylor, Researches into the Early History of Bibliography.-E. B. Tylor, Researches into the Early History of Mankind (i865), and Primitive Culture (1874) ; Julius Lippert, Kul turgeschichte der Menschheit (Stuttgart, 1886) ; J. A. G. Pauschmann, Das Feuer and die Menschheit (Erlangen, 1908) ; S. C. GilFillan, "The Coldward Course of Progress," Political Science Quarterly (5920) ; V. Stefansson, The Northward Course of Empire (1922) ; Walter Hough, "Fire as an Agent in Human Culture," U.S. National Museum Bulle tin 139 (1926) ; W. G. Sumner and A. G. Keller, The Science of Soci ety (New Haven, 1927) ; E. Huntington, "The March of Civilization," Harper's Magazine (1928) . (EL. HN.)