Discussions on Climate and CosmologyE. Stanford, 1889 - 327 páginas |
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accumulation amount of heat Antarctic continent Antarctic ice Antarctic regions aphelion aqueous vapour Arctic regions assume bergs Carboniferous cold condition of things consequently continuous denudation deposits derived earth eccentricity effect elevation enormous Eocene equal equator evidence existence extent fact feet fogs freezing-point geographical conditions geological geologists glacial condition glacial epoch glacial period glacier globe gravity greater Greenland Gulf Stream heat received heat-rays ice-cap ice-sheet icebergs inches increase interglacial periods Island land land hemisphere latitude layer lower mammoth mass mean temperature melting melting-point miles Miocene motion nebulæ northern hemisphere ocean currents ocean-currents Old Red Sandstone particles perature perihelion physical agencies physical causes polar regions Pole present probably produce Professor Newcomb quantity radiation result says sea-level sheet Siberia Silurian Sir Wyville snow and ice snowfall southern stars sufficient summer sun's heat suppose surface theory thickness tion velocity Wallace warm water hemisphere winter solstice
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Página 54 - Were it not for the ice, the summers of North Greenland, owing to the continuance of the sun above the horizon, would be as warm as those of England ; but, instead of this, tho » Tyndall, " On Heat,
Página 288 - In the same way as the distances between the different planetary systems are not calculated by miles but by Sirius-distances, each of which comprises millions of miles, so the organic history of the earth must not be calculated by thousands of years, but by palaeontological or geological periods, each of which comprises many thousands of years, and perhaps millions, or even milliards, of thousands of years.
Página 273 - ... removed from the general surface in one year ; and there seems no danger of our overrating the mean rate of waste by selecting the Mississippi as our example, for that river drains a country equal to more than half the continent of Europe, extends through twenty degrees of latitude, and therefore through regions enjoying a great variety of climate, and some of its tributaries descend from mountains of great height. The Mississippi is also more likely to afford us a fair test of ordinary denudation,...
Página 180 - Sannikow found the skulls and bones of horses, buffaloes, oxen, and sheep in such abundance that these animals must formerly have lived there in large herds. At present, however, the icy wilderness produces nothing that could afford them nourishment, nor would they be able to endure the climate. Sannikow concludes that a milder climate must formerly have prevailed here, and that these animals may therefore have been contemporary with the mammoth, whose remains are found in every part of the island."...
Página 50 - At high elevations the air is dry, and allows the heat radiated from the snow to pass into space ; but at low elevations a very considerable amount of the heat radiated from the snow is absorbed by the aqueous vapour which it encounters in passing through the atmosphere. A considerable portion of the heat thus absorbed by the vapour is radiated back on the snow ; but the heat thus radiated being of the same quality as that which the snow itself radiates, is on this account absorbed by the snow. Little...
Página 201 - The regularity of this diminution leaves it almost without a doubt that the layers observed are in the same category, and that therefore the diminution is due to subsequent pressure or other action upon a series of beds, which were at the time of their deposition nearly equally thick. About...
Página 177 - These are," says Mr. Howorth, " found even more abundantly on the banks of the very short rivers east of the Lena. They are found not only on the deltas of these rivers, but far away to the north, in the islands of New Siberia, beyond the reach of the currents of the small rivers, whose mouths are opposite those islands." But a more convincing proof is that " they are found not only in North Central Siberia, where the main arteries of the country flow, but in great numbers east of the river Lena,...
Página 6 - There is no geological evidence to show that, at least since Silurian times, the Atlantic and Pacific were ever in their broad features otherwise than they are now — two immense oceans separated by the Eastern and Western continents — and there is not the shadow of a reason to conclude that the poles have ever shifted much from their present position. On this point I cannot do better than quote the opinion recently expressed by Sir William Thomson : "As to changes of the earth's axis, I need...
Página 180 - where the lakes on the tundra have grown small and shallow, we find on and near their banks a layer of turf, under which, in many places, are remains of trees in good condition, which support the other proofs that the northern limit of trees has retrogressed, and that the climate here has grown colder. I found, on the way from Dudino to the Ural Mountains, in a place where larches now only grow in sheltered rivervalleys, in turf on the top of the tundra, prostrate larch trees still bearing cones...
Página 156 - And as we have seen that during the last three million years the eccentricity has been almost always much higher than it is now, we should expect that the quantity of ice in the southern hemisphere will usually have been greater, and will thus have tended to increase the force of those oceanic currents which produce the mild climates of the northern hemisphere