Notre Dame Scholastic, Vol. 18, No. 32

Disoe quasi semper victnms; vive quasi eras moriturus. VOL. XVIII. NOTRE DAME, INDIANA, APRIL iS, 18S5. No. 32. Memory. above the sea level the colder the atmosphere is. Now, when the vapor reaches the line of perpetual Dust thou art, O mighty Past, but whither snow, it is first condensed into water, and the Send the flying motes of time? water is then converted into snow. When, there We who love and laugh, yet surely wither fore, the current carrying the aqueous vapor strikes ' With the woes of every clime. agfainst a mountain %vhose summit reaches the line of pei-petual snow, it is forced over it by the on Sailing, with our phantom fleets of glory, coming current; some of the vapor is chilled and Down the waves engulfing all, falls in the form of snow on top of the mountain. Graving on white marble heights a story The snow, by alternate thawing and freezing and Broken with the falling wall. liy the action of its own weight, is converted into Weak and hollow sound our voices ice, and we have a glacier. In the void of the unknown. There are three lines to be distinguished in the While the Resurrection peal rejoices. atmosphere about the earth, namel}': The line of Pain and death about us moan. perpetual snow, the mean line of ,32° F., and the line of the lower limit of the glacier. The line of Rank on rank the tender germs are rising perpetual snow forms- a spheroid around the earth. Through the clods that held them fast, At the equator it is from 16,000 to 17,000 feet Bui no early dream, our hearts surprising above the level of the sea, and it touches the sea Rises, living from the past. level near the poles. The mean line of 32°-F. coin MARION MUIR. cides at the equator with the line of perpetual snow, but it touches the sea level at about 66° Qlaoiera.* North and South latitude. The line of the lower limit of the glacier is, at the equator, nearly the same as the preceding two, and touches the sea In mountainous regions, where the summits of level at about 50° North and South latitude. These the mountains reach the line of perpetual snow, the lines are very in-egular. For instance, in Chili, valleys are sometimes occupied by large masses the glaciers touch the sea level at 46° .50' South of ice and compact snow which are constantly mov latitude. ing downward; these masses of ice we call glaciers. Their formation and motion I shall at once pi'oceed The highest part of a glacier is called perpetual to discuss. snow; lower down is neve—granular snow—which is intermediate between* the snow and the ice; The formation of glaciers is due to the ac still farther down is the true glacier ice; and, tion of the sun on water. When the sunbeams finally, the river, which is formed by the melting fall upon the sea, the water is warmed at the sur of the glacier ice. A fact which should not pass face. This warm layer of water sends up a large unobserved is that at the end of every glacier there quantity of aqueous vapor which, being lighter is a river; and thus we see that the water which than the air, rises; when it has reached a cer comes from the ocean is again I'eturned to the ocean tain height it is caught by the upper trade winds after undergoing a series of changes. and carried towards the poles. But before the The size of the glaciers varies greatly. In the vapor reaches the poles great changes take place. Alps we find some that are as much as fifteen The aqueous vapor, on leaving the equatorial miles in length, and from one half to three miles regions, is held up by the warm air which in breadth. These again vary in thickness, some forms the upper trade winds; when it reaches a being four hundred feet thick, while others are as certain elevation it is condensed by the action much as six hundred feet thick. In the Hyma- of the colder atmosphere above, and falls in laya Mountains, they are of much more gigantic the form of rain or snow. If the atmosphere is proportions, because the Hymalaj-^a Mountains are sufficiently cold it falls in the form of snow, other so much higher than the Alps that there is never wise as rain. We know that the higher we are any appreciable thawing on their summit. But it is only from those of the Arctic regions that we can * Paper read before the Notre Dame Scientific Associa tion by CHARLES C. KOLARS. form an adequate idea of the size of glaciers. Green- 502 THE NOTRE DAME SCHOLASTIC, land is apparently covered with a sheet of ice several The transporting power of the glaciers is enor thousand feet thick. The Great Humboldt glacier, mous and follows no. law laid down for that of a in Greenland, at the point where it enters the sea, river. • Large bowlders ai"e carried down with as is over forty-five miles wide, and over three hun much -.ease as the finest dust. One bowlder, de dred feet thick. In the temperate regions of North scribed by Professor Forbes, contained 244,000 America glaciers are to be found only on the Pacific cubic feet. Coast in the Sierra and the Cascade ranges. We have now learned how glaciers are formed, Glaciers equal in size to those of the Alps have and we have also learned that they are in constant been found on Mt. Shasta and especiall}- on Mt. motion, let us now consider the s^eneral laws sfov- Rainier, erning their movement. Naturallj"^, we would suppose that the surface of These are seven in number. They are as follows: a glacier is smooth and level; but such is not always (1) The centre of the glacier moves faster than the case, owing to the accumulation of stone and the margins. This is proved by the actual meas earth on its surface. A stone lying on the ice pro urements made by Messrs. Agassiz, Forbes, and tects the ice directly under it from the action of the Tyndall. In 1841 M. Agassiz caused six piles to sun's rays, which, however, thaw the surrounding be driven into the glacier of Unteraar, and noted ice, and in time pillars are thus formed. When the their position. In 1842 their displacement was pillars are some twelve or fifteen feet high the stone found to be as follows: 160 feet, 225 feet, 269 feet, slides off by reason of the ice thawing more on 245 feet, 210 feet, and 125 feet respectively. The one side than on the others. The stone then settles middle figures here correspond to the stakes driven on the lower portion of the ice and the same oper in the middle of the glacier, hence we see that the ation is repeated over and over again.' Now, con velocity of the middle is nearly twice that of the sidering that the number of stones on top of the sides. glacier is sometimes great, it necessarily follows On Jnly 21, 1857, Prof, Tj'ndall measured the that the surface is very irregular. Again, the motion of the glacier M&r de Glace^ below Mon- earth which accumulates on top of the glaciers, tanvert. Eleven stukes were driven into the ice, when not too thick to allow the heat rays of the and, beginning on the eastern side, their displace sun to pass through, absorbs them and the ice di ment in twenty-four hours was found to be as fol rectly under it thaws more rapidly than the ice lows: 20-23-29-30-34—2S-25—35-25-18-9 inches surrounding it. Again, there' are ^fissures or cre respectively. Here, again, the middle numbers cor vasses which are often from ten to twenty feet respond to the displacement of the middle stakes. On wide, and often several hundred feet deep. These July 23, in the same year, he measured the motion are sometimes formed by the change of the slope of the glacier at Les Fonts, Here, ten stakes were of the bed of the glacier. As all these irregu used, and, again beginning on the eastern side, larities are sometimes entirely concealed by cover their displacement in twenty-four hours was found ing of snow, the travelling in glacial regions is to be 13-15—16-18-20-23—23—22-1-7—15 inches re rendered very dangerous. spectively. On July 38, he measured its motion at The glaciers are sometimes covered more or less Trdaporte. Here six stakes were driven into the with loose stones and earth, which they gather ice, and, again beginning on the eastern side, their from the fallingf of cliffs on either side.' Some- displacement in twentj'^-four hours was found to be" times the whole surface of the glacier is covered 15—18-19-17—15—13 inches respectively. In all with these loose stones and earth, but more generally these measurements the middle numbers, corre theji- are to be found in lines on the surface of. the sponding to the middle stakes, are the greatest, glacier. These are called Moraines. which shows clearl}'^ that the central portion of the There are three kinds of moraines, viz., lateral, glacier moves faster than the sides. medial, and terminal. Lateral moraines are lines But we also observe that below Montanvert the of earth and stone on the two sides of.

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