And the European, still unsatisfied with all he has achieved in speed and comfort, looks to more rapid and easier modes of conveyance. Scientific men have been for many years engaged in experiments by means of which they hope to replace the ocean by the atmosphere as a public highway for nations; and the currents of air rushing in every direction with the velocity of the most rapid winds may yet be used by our children instead of rivers, thenceforth deserted, and of ocean-streams at last left empty and waste as before the voyages of Columbus and De Gama. All this constitutes a positive and stern fact staring us in the face, and giving to the Caucasian race a power of which our ancestors would never have dreamed. And if all this is to be the only result of man's activity--the attainment of merely worldly purposes--God, whose world this is, may look down on it from heaven as on the work of Titans preparing to attack his rights, and He will know how to turn all these mighty efforts of the sons of Japhet to his own holy designs. He may use a small branch of that great race, preserved purposely from the beginning unsullied by mere thrift, and prepared for his work by long persecution, a consideration which we shall examine later on. Meanwhile the great mass of the European family is allowed to go on in its wonderful undertaking; and we turn to it yet a short while. As if to favor still more directly this work of the unification of the globe, Providence has placed at the disposal of the prime movers in the enterprise pecuniary means which no one could have foreseen a few years ago. In 1846, on a small branch of one of the great rivers of California, a colonist discovers gold carried as dust with the sand, and soon a great part of the country is found to be immensely rich in the precious metal. That first discovery is followed by others equally important, and after a few years gold is found in abundance on both sides of a long range of the Rocky Mountains; again in the north, nearly as high up as the arctic circle. North America, in fact, is found to be a vast gold deposit. Australia soon follows, and that new continent, whose exploration has scarcely begun, is said to be dotted all over by large oases of auriferous rock and gravel. In due time the same news comes from South Africa, where it has been lately reported that diamonds, in addition to gold, enrich the explorer and the workman. It is needless to speak of mines of silver and mercury after gold and diamonds; but the result is that the European race is straightway provided with an enormous wealth commensurate with the immense commercial and manufacturing enterprises required for the establishment of its supremacy all over the globe. There is work, therefore, for all the ships afloat; others and larger ones have to be constructed; and modern engineering skill places on the bosom of the deep sea vessels which few, indeed, of the greatest rivers can accommodate in their channels and bays.