structures of our cities, the influence of local resources is plain.

Influences on Migration and Commerce

The movements of man show a clear response to nature. Down to the seventeenth century the oceans offered the greatest obstacle to the migratory hordes, and not until the advent of steam power in the nineteenth century did the oceans really become safe and easy highways. Yet the South Sea islanders had made wide voyages in their little canoes. As checks to man's movements deserts probably occupy the second place and, owing to their shifting sand and the danger of sudden washouts, are still great handicaps. Third in importance have been the great mountain ranges and they probably rank first to-day considered in relation to modern methods of transportation and the cost of lifting heavy trains over the divides. There have always been passes through the mountain ranges and man's route has always run through the pass, hence the pass has been of great importance in human history. The Brenner Pass through which the Germans made their way into the Po Valley was largely responsible for the commercial life of Augsburg, Ratisbon, Nuremberg, Leipzig, and, in part, Venice. Students of American history well know the importance of the Mohawk Valley, Cumberland Gap, South Pass and Truckee Canyon. Rivers have been both obstacles and highways. The course of development has been somewhat as follows. When man began a migration he followed the easiest road. Perhaps he ascended a river by boat until he reached the fall line and there, owing to necessity of changing to smaller boats, a town arose which became a city. It may be that he followed the general course of a stream with his stock keeping to the edge of the hills to avoid the marshes of the banks. If population grew and trade sprang up his permanent road followed his early trail, just as in America the white man followed the trail of the

Indian and as the Indian himself probably followed an earlier animal trail. The railroad was invented and it took the same general course. Through the low Mohawk Valley, 445 feet above the sea level, was the line of march to the Great Lakes and the West. Albany, Troy, Utica, Rochester and Buffalo come into being and the valley is densely populated while the Catskills near by are almost uninhabited. It is interesting to speculate what would have been the history of America had the St. Lawrence been navigable from the ocean to the lakes. Where, for instance, would the capital of the country have been located? The location of man's towns and highways is not, then, a matter wholly of accident. Political considerations have determined the site of a few cities like Petrograd, Washington, and Canberra, the new capital of Australia, and even with reference to these we might ask the cause of the political considerations. Migrants go to the places where they have opportunities for gaining a livelihood, and booster's campaigns have little lasting influence.

Psychical Influences

Strange as it may seem, man lives in two worlds, not one. As a part of the first he receives impressions through his senses and is stimulated to action. He then reflects, combines and mixes his memory and impressions, and creates a new world out of the old elements. The first is a world of rocks, trees, animals, birds, men, all tangible. The second is a world of spirit, which may be seen or felt but seldom grasped; immaterial but often dwelling in carnal shapes. It is not easy, always, to tell where the boundary lines between the worlds are. Man requires light in order to see but often he perceives more things when it is dark. Ghosts, fairies, demons, goblins all dwell in the second world. The scientist is studying and classifying the material world but poets and dreamers hold sway in the second. Granted this confusion, certain facts appear.

It is man's contact with the material world which has started his mind into activity. Nature by determining his activities plots the road of his development. Why is it that in our part of the world the weather holds first place in our conversation? It is claimed that in arid lands the primary topic is water. Here, then, is a topic in which two men, even though they be strangers, are sure to have a common interest. The Samoyeds of northern Russia have a dozen terms to distinguish the shades of brown and gray of their reindeer. The Malay vocabulary is rich in nautical terms. Language always reflects interest. Get a man and a woman to describe some woman's costume and ponder the result. A new invention like the automobile or radio almost revolutionizes common idioms. Language also gives a clew to the efficiency of our sense organs. Most of our impressions are through the eye and terms for colors and forms are numerous. Contrast our poverty in adjectives to describe odors and see how inadequate our language would be for a dog. We note resemblances rather than differences and only much practice enables us to distinguish similar forms. How many can tell a song sparrow from an English sparrow, a spruce from a fir? It is easy for a farmer to understand and sympathize with another farmer but it is just as easy for him to misunderstand and revile a Wall Street banker. Human standards grow out of human backgrounds and if the backgrounds are different understanding and sympathy are hard.

Man's emotions are aroused by many things in nature. Dexter writing of the dry winds of Colorado says: "During the prevalence of such, the humidity is invariably excessively low, and in the dry air there seems to be set up, by the movement of the wind particles and the leaves and grasses set in motion by them, an electrical state which in some undetermined way makes havoc with the emotions." Huntington writes: "In eastern Turkey the hot desert wind causes the whole community to become cross and irritable. I have

there seen a missionary, a man of unusual strength of character, shut himself up in his study all day, because he knew that he was in danger of saying something disagreeable." Hann claims that: "Damp air and increased pressure have the following physiological effects:-nervous depression; quiet sleep; increased elimination of carbon dioxide; slower circulation of the blood. Dry air and decreased pressure, on the other hand, have these effects:-nervous excitement; sleeplessness; quickened pulse; a dim skin and a decreased temperature." 10 Many witnesses have testified as to the influence of the winds.

Writing of the Yukon, a resident says that all are much affected by the highly electrified winter atmosphere:

By the end of March (the most unendurable month in the North, physically and psychically) we are most of us avoiding and hating one another. I have learned since that this is all a yearly phenomenon and will pass surely and quickly with the breaking of the ice in the river. . . But there are always the March scandals . . . conventional restraint is broken . . someone goes crazy or jumps a martial claim . . . or a lonely miner pulls a gun on his best friend with whom he has been living all winter in a too isolated intimacy. . . . To tell the truth, the spring scandal brings a blessed relief. With the spring comes a truly new life . . . neighbors who have not spoken for weeks greet one another across fast-melting back lots.11

Every one is more or less conscious of the influence of nature on his emotions. The entrancing beauty of some moonlight scene, the majesty of a snow-capped mountain, the grandeur of the oncoming storm, the restfulness of a mountain pasture filled with sheep are the stuff of which poems are made but for most of us the actual creation is by proxy. Man is terrified by the thunder, he is soothed by the gentle fall of the rain or the music of the waterfall. Color of landscape and cloud moves him deeply. Here is a great field not yet clearly defined and studied. Hellpach has made

a preliminary survey but much study and many experiments must be made ere we can hope for much understanding.

Nature not only stimulates our mental machinery into action but sets the limits beyond which it may not go. Our ideals develop out of the world we know whether we consider our experiences good or bad. The Navajo shepherd, accustomed to the arid country where cattle and sheep must graze over large areas, listens to his fellow tribesman tell of the wonders of Chicago and believes it all until the narrator says that on his way he passed vast fields where the grass grew so thick that the blades pushed against each other, and then he is convinced at once that the narrator is lying. Grass does not grow that way, and he knows grass. The Hopi woman hears with amazement of the location of New York City almost surrounded by water and thinks that conditions there must be heavenly whereas our preacher is likely to describe it in other terms. He who knows "the desert's scorching sand" can picture a future place of punishment in no stronger terms; the plains Indian portrays heaven as a happy hunting ground; the dweller in frigid regions can imagine no future place too hot for comfort. "In all the forms of its creeds and cults, humanity does not seem able to get away from its earthly patterns. The Elysian fields, the Valhalla, the life that now is reflected upon the life beyond, are all shaped after models familiar upon the earth." 12 Even our wildest dreams but consist of bizarre combinations of many elements already familiar to us in everyday life. We picture God as a spirit, but it is significant that we picture him in human form for that is the highest thing we know.

CIVILIZATION AND CLIMATE

In the previous chapter it was suggested that each variety of plant or animal flourished best under certain conditions to which the name optimum was given. Can such an optimum