the extreme cold which Nansen found in Greenland, and which makes that interior a second pole of cold along with that in the interior of Siberia, is fully explained.

Yet the winds contribute to the warming of the polar sea. They drive the waters from warmer regions in wide superficial currents into the higher latitudes, where, being heavier in consequence of their greater content of salt than the fresher water resulting from the melting of the glaciers and the ice, and from the outpour of the great Siberian rivers, they sink beneath them to the bottom and keep the temperature of the sea constantly above the freezing-point. The colder, lighter water has to give way to these undersea currents, and flows into the Atlantic Ocean, cooling the American coasts. At the south pole currents flow in from all the seas, and superficial waters spread into all the oceans.

How shall we account for the masses of polar ice, for the immense icebergs, and the glaciation of Greenland? The snowfall of the polar regions is light. The air is nowhere dryer than over the cold glacier ice, as is proved every day in Switzerland by the quickness with which clothes dry when hung over it. At the same time the ice is covered with extremely fine, hardly visible snow crystals. If we boil water in a retort which is connected with another vessel containing a piece of ice, all the steam will pass over on to the ice and deposit itself as ice upon it. The same takes place in a larger degree on the earth, where the retort is the warm evaporating water of the tropical regions, the connectingpipe is the upper atmosphere, and the thickening ice is at the pole. Thus, without any rain or snow falling, all the moisture and all the vapor is withdrawn from the atmosphere by this ice and deposited upon it in fine crystals; and as the influx of air is constant and all-pervading, a never-ceasing supply of frost is going on all the time. In consequence of the larger quantity of moisture, the process is still more marked and regular at the south pole. The explanation of the glaciation of the northern part of our temperate zone during the ice age, still unfound, is a matter of great importance, for the present topography of the land was brought

out and the organic life of the whole earth was modified by it; and it is the general opinion that the solution of the problem is to be found, if it is found, by the study of the polar regions.

In the period immediately preceding the ice age the polar regions were not covered with ice, but had a rich growth of plants, reaching up even to the glaciers of their mountains, and plants were represented in them which are now known only in warmer countries. This was a very noteworthy time in the history of the earth. Organic life, in the continents at least, was in its greatest extension, and, I believe, specificism and diversity. The forests also were more luxuriant than now. And this was the time when man originated. Upon this came the ice age, during which man was scattered over the whole world, and organic beings were divided, according to their capacity to resist the cold, into the three great classes of arctic, temperate, and tropical life-a division which probably existed too during the earlier period, but then only locally, as on mountain ranges. The study of the organic life of the poles is therefore of the greatest importance for the understanding of the history of the organic life of our planet; and the more so because the arctic region has always been an important station for the distribution of organisms. The plants and animals of the south polar lands, on the contrary, and of the pointed southern continental terminations have never shown any permanent community with one another. This peculiar feature of the southern continents appeared very early.

Knowledge concerning the origin and spread of peoples may likewise receive valuable contributions from polar research. That is shown by the Eskimos and their wonderful adaptation to that nature which is so destructive to civilized peoples. In this we have a clear demonstration of the maxim which is one of the most important, if not the most important law of all organic and human life: that what is to be permanent can be brought about only by gradual, extremely slow formation; never by sudden, immediate transition, or by sharp, violent breach.

AMERICA

An Ancient Mexican Palace

By DESIRÉ CHARNAY

JE cleared away rubbish until we reached the floor, following the walls, corners, and openings of the various apartments, as we had done at Tula; and when, three days later, the engineer joined us, ten rooms, forming part of the house, had been unearthed. He was so surprised at our success that, stopping short, he exclaimed: "Why, it is our Tula palace over again!"

And so it was-inner court, apartments on different levels, everything as we had found before, save that here the rooms were much larger and most supported by pillars; one of these chambers measured forty-nine feet on one side, that is, seven hundred and thirty-two feet in circumference. The walls, nearly six feet seven inches thick, are built of stone and mortar, incrusted with deep cement, sloping up about three feet and terminating perpendicularly. The center of the room is occupied by six pillars, on which rose stone, brick, or wood columns bearing the roof.

This is undoubtedly a palace, and these are the reception-rooms; the sleeping apartments were behind; unfortunately they lie under cultivated ground covered with Indian corn, so we are not permitted to disturb them. In the large room we observed small stone rings fixed to the wall, and on each side of the entrance, also fixed to the wall, two small painted slabs. What had been their use? To support lights at night? But how was that possible? For even now the only lights the natives use are ocotes, pieces of

resinous wood, whilst the slabs bear no traces of smoke. I had, it is true, met in the course of my excavations with terra-cotta objects which might have been taken for candlesticks, but to which I had attached no importance, when I suddenly remembered a passage in Sahagun bearing on the subject: "The chandler who knows how to do his work first bleaches, cleans, and melts the wax, and when in a liquid state he pours it on a wick and rolls it between two slabs; he sometimes puts a layer of black wax within a white layer," etc. My first supposition had been right.

Here also the floors and walls are coated with mortar, stucco, or cement, save that in the dwellings of the rich, necessarily few, they are ornamented with figures, as principal subject, with a border like an Aubusson carpet. The colors are not all effaced, red, black, blue, yellow, and white, are still discernible; a few examples of these frescoes are to be seen in the Trocadéro. I am convinced that numerous treasures might be brought to light were regular excavations to be made, but the Mexican Government, which would have most interest in such a work, does not seem to care to undertake it.

Leaving my men under the direction of Colonel Castro, I return to the Path of Death," composed of a great number of small mounds, Tlateles, the tombs of great men. They are arranged symmetrically in avenues terminating at the sides of the great pyramids, on a plain of some six hundred and twenty feet to nine hundred and seventy-five feet in length; fronting them are cemented steps, which must have been used as seats by the spectators during funeral ceremonies or public festivities. On the left, amidst a mass of ruins, are broken pillars, said to have belonged to a temple; the huge capitals have some traces of sculpture. Next comes a quadrangular block, of which a cast is to be found in the main gallery of the Trocadéro.

In the course of my excavations I had found now and again numerous pieces of worked obsidian, precious stones, beads, etc., within the circuit of ants' nests, which these busy insects had extracted from the ground in digging their