around America. India was the object of the polar navigators-Cabot in the fifteenth, Frobisher and Davis in the sixteenth, and Hudson and Baffin in the seventeenth centuries, to name only a few of the most famous. It is astonishing what these daring British and Dutch sailors risked, suffered, and gained.

In the seventeenth century appeared such men as Kepler, Cassini, Newton, and Boyle. The shape of the earth was actively discussed, improved maps were made, and new aims and motives were conceived, the development of which has caused the nineteenth century to be so sharply distinguished from its predecessors. Now knowledge of the earth is sought for itself, and in this respect the polar research of the present has all at once assumed another aspect, under which it is differentiated from that of the past. Northwestern and northeastern passages have been sought in our days, but not in order to reach India. When Maclure achieved the former in 1852 and Nordenskjöld the latter in 1879, the value attached to the discoveries was not that they furnished routes, but that a correct knowledge of the northern coasts of the two continents and rich stores of other scientific information had been gained by them. Fruits like those, no longer the interests of trade, justified the high prizes which the English Government offered for the discovery of the passage, and the costly expeditions which were dispatched for that purpose. The early trade routes became highways for scientfic investigation, and the nature of the polar regions as a whole was inquired into. Such objects were pursued by individuals. Scoresby, while hunting for whales, made constant studies of the highest scientific value of the hydrography, magnetism, and meteorology of the arctic regions; and so did Karl Ludwig Gieseke, afterward Professor of Mineralogy at Dublin, who traveled through East and West Greenland from 1807 to 1813 solely for the thorough study of the geology of their coasts.

Till 1860 the English, and afterward the Americans with them, were in the front as polar explorers. The most important results of their work were the discovery of the

magnetic pole in 1831 by John and James Ross, the definition of the coast of arctic America, and numerous single observations. More recently other nations have come forward -the Danes in Greenland, and the Swedes, whose most illustrious representative is Nordenskjöld. Two German expeditions have been sent to East Greenland, an Austrian expedition under Weyprecht and Preyer has discovered Franz-Joseph Land, the Dutch have explored south of Spitzbergen, the Russians on the northern coast of Siberia, and now with Nansen and Mohn the Norwegians have advanced to the very front. In 1882-83, at the instance of the German Neumayer and the Austrian Weyprecht, a chain of observation stations was established around the pole, to be kept up for a year-an enterprise in which Germany, England, the United States, Russia, Austria, France, Sweden, Norway, and Finland took part. The year 1883 was further marked by Nordenskjöld's return from the inland ice of Greenland, and by Nansen's conception of his scheme for traversing Greenland on snowshoes, which he carried into effect the next year. North polar research is therefore almost exclusively the work of the Germanic nations, for the Russian explorers have been chiefly of that stock. The Romanic nations, no less seafaring people, have kept away from the north pole; but France has done something in south-polar exploration.

The south pole has been comparatively neglected on account of the unfavorable character of its surroundings. Large masses of land are wanting, and the immense wastes of water of the South offer only a few islands possessing neither large mammals nor human inhabitants; while the Eskimos of the North are of incalculable advantage to exploration. Magellan's southern voyage was not followed up for two hundred and fifty years. The first after him to reach high southern latitudes was James Cook, in 1774, and no other similar expeditions followed for fifty years more. Those best known were those of the French under Dumont d'Urville in 1839, of the Americans under Wilkes, and of the English under James Ross, who in 1842 penetrated to

the seventy-eighth degree, the highest southern latitude yet attained. After a year's maintenance of a German station on the South Georgian Islands and of a French station at the southern point of America, both of which belonged to the international system of 1883, and after a few dashes southward in later years, a number of nations-Germany, Austria, England, the United States, and others—are again preparing to cooperate in another polar siege at the austral end of the world for the benefit of science.

Nowhere are more questions to be found for which to seek answers than in the polar regions. Here the magnetoelectric light of the earth manifests itself in the wonderful phenomenon of the northern lights. All the wind currents of the earth press toward the pole, and the sea currents too. Curious dispositions of Nature are found here, with great volcanoes, the outer cones of which are constituted of strata of ice covered with lava, and under the masses of ice we discover remains of plants that demonstrate the presence not so very long ago of a flourishing tropical or subtropical vegetation instead of the present ice. We meet mountains of ice everywhere, and everywhere the arctic region is

sublime.

There is thus much to observe and much to learn in these regions for the satisfaction of our irresistible longings. First, we are able to study in the polar regions the division of land and sea, the size, elevation, and topography of the land-the whole question, in short, of polar geography. The form of the earth's surface is not casual, but is the result of interactions of the crust and the interior of the globe. The discovery by Nansen's expedition of the profundity of the polar sea tallies with Prof. Mohn's observations of the great depths between Greenland and Spitzbergen and with those of the fiords and interinsular channels of the North Atlantic. Further, the sea bottoms are penetrated by volcanoes, some of them still active-here single, as in Jan Mayen Island, there in groups, as in Franz-Joseph Land and Fire Island. A marked difference exists in this respect between the Atlantic half of the polar regions north of Europe

and eastern North America, where disturbance and divisions of the land are the rule, and the Pacific side, north of Siberia and western America, where quiet prevails, with regular coast forms and few islands. The lands on the Atlantic side have, moreover, been gradually rising for an incalculable length of time, and are still rising, while those on the opposite side have, until very recently, been subsiding. These facts, selected as examples from a great number of phenomena, may serve to illustrate how important is a knowledge of the polar regions to that of the earth as a whole. Its importance is, in fact, quite beyond comprehension.

So the magnetism of the earth, the colored beams of the northern lights, the flickering of their draperies and bands, are of interest far beyond their relations to the earth alone; for the movement of the magnetic elements reflects the processes of the sun's atmosphere, and may be connected with the immense periods of the revolution of our solar system.

A relation between the northern lights and the weather has been established by repeated observations, and that brings us to another group of phenomena, those of meteorology, which are of interest to the whole earth, and are especially remarkable in the polar regions. An interchange of great wind currents between the equator and the poles is constantly going on, upon which the movements of the atmosphere and the pressure in the intermediate regions are ultimately dependent, and the study of the atmospheric phenomena of the polar regions is indispensable to our proper knowledge of them.

The excess of heat at the equator forces masses of air into the highest regions of the atmosphere; the congestion at the pole, the necessary consequence of accumulation there, forces them back to the earth. On their way through the higher regions these masses are attenuated and cooled, so that, even when condensed at their sinking, they cannot overcome the polar cold; and as they bring little moisture, and consequently little cloudiness, the radiation of heat goes on continuously during the long polar night; the more so because snow and ice are extremely good radiators. Hence