of civilization, saw such changes effected in the practical affairs of their everyday lives as had not been wrought before during the entire historical period. Their fathers had travelled in vehicles drawn by horses, quite as their remoter ancestors had done since the time of higher barbarism. It may be doubted whether there existed in the world in the year 1800 a postal service that could compare in speed and efficiency with the express service of the Romans of the time of Caesar; far less was there a telegraph service that could compare with that of the ancient Persians. Nor was there a ship sailing the seas that a Phoenician trireme might not have overhauled. But now within the lifetime of a single man the world was covered with a network of steel rails on which locomotives drew gigantic vehicles, laden with passengers at an hourly speed almost equalling Caesar’s best journey of a day; over the land and under the seas were stretched wires along which messages coursed from continent to continent literally with the speed of lightning; and the waters of the earth were made to teem with gigantic craft propelled without sail or oar at a speed which the Phoenician captain of three thousand years ago and the English captain of the 18th century would alike have held incredible.
There is no need to give further details here of the industrial revolutions that have been achieved in this newest period of civilization, since in their broader outlines at least they are familiar to every one. Nor need we dwell upon the revolution in thought whereby man has for Social and political organization. the first time been given a clear inkling as to his origin and destiny. It suffices to point out that such periods of fermentation of ideas as this suggests have probably always been concomitant with those outbursts of creative genius that gave the world the practical inventions upon which human progress has been conditioned. The same attitude of receptivity to new ideas is pre-requisite to one form of discovery as to the other. Nor, it may be added, can either form of idea become effective for the progress of civilization except in proportion as a large body of any given generation are prepared to receive it. Doubtless here and there a dreamer played with fire, in a literal sense, for generations before the utility of fire as a practical aid to human progress came to be recognized in practice. And—to seek an illustration at the other end of the scale—we know that the advanced thinkers of Greece and Rome believed in the antiquity of the earth and in the evolution of man two thousand years before the coming of Darwin. We have but partly solved the mysteries of the progress of civilization, then, when we have pointed out that each tangible stage of progress owed its initiative to a new invention or discovery of science. To go to the root of the matter we must needs explain how it came about that a given generation of men was in mental mood to receive the new invention or discovery.
The pursuit of this question would carry us farther into the realm of communal and racial psychology—to say nothing of the realm of conjecture—than comports with the purpose of this article. It must suffice to point out that alertness of mind—that all mentality—is, in the last analysis, a reaction to the influences of the environment. It follows that man may subject himself to new influences and thus give his mind a new stimulus by changing his habitat. A fundamental secret of progress is revealed in this fact. Man probably never would have evolved from savagery had he remained in the Tropics where he doubtless originated. But successive scientific inventions enabled him, as has been suggested, to migrate to distant latitudes, and thus more or less involuntarily to become the recipient of new creative and progressive impulses. After migrations in many directions had resulted in the development of divers races, each with certain capacities and acquirements due to its unique environment, there was opportunity for the application of the principle of environmental stimulus in an indirect way, through the mingling and physical intermixture of one race with another. Each of the great localized civilizations of antiquity appears to have owed its prominence in part at least—perhaps very largely—to such intermingling of two or more races. Each of these civilizations began to decay so soon as the nation had remained for a considerable number of generations in its localized environment, and had practically ceased to receive accretions from distant races at approximately the same stage of development. There is a suggestive lesson for present-day civilization in that thought-compelling fact. Further evidence of the application of the principle of environmental stimulus, operating through changed habitat and racial intermixture, is furnished by the virility of the colonial peoples of our own day. The receptiveness to new ideas and the rapidity of material progress of Americans, South Africans and Australians are proverbial. No one doubts, probably, that one or another of these countries will give a new stimulus to the progress of civilization, through the promulgation of some great epochal discovery, in the not distant future. Again, the value of racial intermingling is shown yet nearer home in the long-continued vitality of the British nation, which is explicable, in some measure at least, by the fact that the Celtic element held aloof from the Anglo-Saxon element century after century sufficiently to maintain racial integrity, yet mingled sufficiently to give and receive the fresh stimulus of “new blood.” It is interesting in this connexion to examine the map of Great Britain with reference to the birthplaces of the men named above as being the originators of the inventions and discoveries that made the close of the 18th century memorable as ushering in a new ethnic era. It may be added that these names suggest yet another element in the causation of progress: the fact, namely, that, however necessary racial receptivity may be to the dynamitic upheaval of a new ethnic era, it is after all individual genius that applies its detonating spark.
Without further elaboration of this aspect of the subject it may be useful to recapitulate the analysis of the evolution of civilization above given, prior to characterizing it from another standpoint. It appears that the entire period of human progress up to the present may be Nine periods of progress. divided into nine periods which, if of necessity more or less arbitrary, yet are not without certain warrant of logic. They may be defined as follows: (1) The Lower Period of Savagery, terminating with the discovery and application of the uses of fire. (2) The Middle Period of Savagery, terminating with the invention of the bow and arrow. (3) The Upper Period of Savagery, terminating with the invention of pottery. (4) The Lower Period of Barbarism, terminating with the domestication of animals. (5) The Middle Period of Barbarism, terminating with the discovery of the process of smelting iron ore. (6) The Upper Period of Barbarism, terminating with the development of a system of writing meeting the requirements of literary composition. (7) The First Period of Civilization (proper) terminating with the introduction of gunpowder. (8) The Second Period of Civilization, terminating with the invention of a practical steam-engine. (9) The Upper Period of Civilization, which is still in progress, but which, as will be suggested in a moment, is probably nearing its termination.
It requires but a glance at the characteristics of these successive epochs to show the ever-increasing complexity of the inventions that delimit them and of the conditions of life that they connote. Were we to attempt to characterize in a few phrases the entire story of achievement thus outlined, we might say that during the three stages of Savagery man was attempting to make himself master of the geographical climates. His unconscious ideal was, to gain a foothold and the means of subsistence in every zone. During the three periods of Barbarism the ideal of conquest was extended to the beasts of the field, the vegetable world, and the mineral contents of the earth’s crust. During the three periods of Civilization proper the ideal of conquest has become still more intellectual and subtle, being now extended to such abstractions as an analysis of speech-sounds, and to such intangibles as expanding gases and still more elusive electric currents: in other words, to the forces of nature, no less than to tangible substances. Hand in hand with this growing complexity of man’s relations with the external world has gone a like increase of complexity in the social and political organizations that characterize man’s relations with his fellow-