Wherever glaciers are easily approached they form a great attraction for the summer tourist. The glistening white snow fields circled by the green foliage of the lower slopes, with the glaciers descending in long, white arms down the valleys,pouring out turbulent, milky- colored streams from their lower ends, and here and there covered with boulders and long, dark lines of medial moraines, form a picture which once seen is never forgotten, and the enticement of whichlures the traveler again and again to revisit the fascinatingROCKS POLISHED BY A GLACIER.
The glacier in the background recently extended down over these rocks.
scene. The exhilaration of a climb over the pathless ice with the bright summer sun shining upon it, the bracing air, and the ever changing novelty of the surroundings make a summer among the glaciers almost like a visit to a land of enchantment.
For this reason Switzerland has become the summer playground of Europe and America, and there the tourist crop is the best crop that the natives raise, and the scenery is more productive than the soil. Norway, with the additional beauty of its fiords, is fast becoming another Mecca of the tourist, and this region, denuded and made barren by the ancientMOUNT HOOD.
A view taken in the fall when the mountain is covered with snow, although the surrounding country is still green.
glaciers, is now becoming rich and prosperous because of the glacial remnants still left. The high Sierras are each year enticing greater and greater numbers of travelers to enjoy their wonderful beauties and their invigorating climate.
167.Greenland and the Antarctic Ice Fields. -The whole of theisland of Greenland is covered with a deep sheet of ice except a narrow border along a portion of the coast and the part of the island north of 82°, which has little precipitation. The extent of the ice sheet is nearly equal to the area of all the states of the United States east of the Mis- sissippi and north of the Ohio. The depth of the ice is not known, but probably in some places is at least several thousand feet. Although along the coast mountains rising from 5000 to 8000 feet are not un- common, yet in the interior the thickness of the ice is so great that no peaks rise above it.
The surface of the inland ice is a smooth snow plain. Extending from this ice field are huge glaciers having at their ends a thickness of from 1000 to 2000 feet. One of these has a rate of motion of nearly 100 feet per day in summer, the highest rate ever observed in a glacier.
The average movement throughout the year on the border of the ice sheet is probably not more than two inches a day.
In the Antarctic region an area vastly greater than Greenland is covered with ice probably of a greater thickness. Although little is known about this ice cap, it is thought by someA VIEW OF THE JUNGFRAU.
Showing the snowy mountains and verdant valleys which make Switzerland the delight of the tourist.
explorers to be nearly as large as Europe and to rest partly on an Antarctic continent and partly on the sea bottom.
168.Icebergs.
Experiment 129. -Fill a beaker so full of ice water that if any more is added it will run over. Put carefully into the beaker a piece of ice, and catch in another beaker the water which runs out. After all the water which readily overflows has been caught in the second beaker, carefully push the ice into the water till it is entirely submerged, and catch in a third beaker the water which overflows. The experiment must be done with considerable quickness, so that the ice will not melt between the two steps.
The water in the second beaker
is equal to the volume of the ice submerged when it floats, and that in the third beaker to the volume of the part out of water when the ice floated. The two together are equal to the whole volume of the ice. Measure in a graduate or weigh on a balance these two volumes of water. (A cubic centimeter ofwater weighs a gram.) Determine
AN ICEBERG.
the part of a floating block of ice that is out of water. Would the amount of ice out of water be greater or less if the water were salt? This can be demonstrated by dissolving a considerable quantity of salt in the ice water and very rapidly repeating the experiment.
When a glacier extends out into the sea, the water tends to float the ice. If it extends out into deep enough water, the buoyancy of the water will be sufficient to crack the ice, and the end of the glacier will float off as an iceberg. Glacial ice is about eight ninths under water when it floats.
Icebergs may float for long distances before they melt. In the North Atlantic the steamer routes are changed in the summer months for fear of running into floating bergs. Some of the most appalling disastersBOWLDERS AND SAND LEFT BY A RETREATING GLACIER.
of the sea have been due to ships colliding with icebergs. As the berg melts, the rocks and gravel or whatever it may have upon it drop into the sea, so that the waste brought down to the sea by the glacier may be spread over the sea bottom far away from the place where it originated. Much of the knowledge of the geology of the Antarctic continent has been gained from the boulders dredged up at sea.
Although icebergs in the northern seas are sometimes very large, those in the Antarctic region are vastly larger. They have been seen extending above the water 200 or more feet with broad flat tops miles in length. They were indeed huge floating islands of ice.
169.Glacial Formations. -In a region which has been glaciated,peculiar deposits are found which occur nowhere else. Sometimes the end of a glacier remains comparatively stationary over an area for a considerable time, owingto the advance of the ice being just balanced by the melting. In this case, the morainic material which has collected on the top isdeposited over the surface, forming irregular heaps ofA DRUMLIN.
These low, smooth, rounded hills, like that seen in the background, usually extend nearly north and south.