Discussions on Climate and CosmologyA. & C. Black, 1885 - 327 páginas |
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accumulation amount of heat Antarctic ice Antarctic regions aphelion aqueous vapour Arctic regions assume bergs Carboniferous cold condition of things consequently continuous denudation deposits earth eccentricity effect elevation enormous Eocene equal equator equatorial evidence existence extent fact Faroe Islands 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 interglacial periods Island land land hemisphere latitude layers lower mammoth mass mean temperature melting melting-point miles Miocene motion nebula northern hemisphere ocean currents ocean-currents Old Red Sandstone particles perihelion physical agencies physical causes polar regions Pole present probably produce Prof 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 Tertiary period 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 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 288 - In the same way as the distances between the different planetary systems are not calculated by miles but by Sirius-distances, each of...
Página 182 - 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."f...
Página 50 - ... thus radiated being of the same quality as that which the snow itself radiates is on this account absorbed by the snow. Little or none of it is reflected like that received from the sun. The consequence is that the heat thus absorbed accumulates in the snow till melting takes place. Were the amount of aqueous vapour possessed by the atmosphere sufficiently diminished, perpetual snow would cover our globe down to the sea-shore. It is true that the air is warmer at the lower than at the higher...
Página 161 - Whenever the area became wanner, the descendants of semi-tropical forms would gradually creep further and further north, whilst the descendants of cold-loving plants would retreat from the advancing temperature, vice versd. Whenever the area became gradually colder, the heat-loving plants would, from one generation to another, retreat further and further south, whilst the cold-loving plants would return to the area from which their ancestors had been driven out. In each case there would be some lingering...
Página 179 - 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 251 - The crystal will not form to suit the cavity, the cavity must be made to contain the crystal. And what holds true of one molecule, holds true of every molecule which melts and resolidifies. This process is therefore going on incessantly in every part of the glacier, and in proportion to the amount of heat which the glacier is receiving. This internal molecular pressure, resulting from the solidifying of the fluid molecules in the interstices of the ice, acts on the mass of the ice as an expansive...
Página 158 - 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
Página 5 - A continent ten times the size of Europe elevated two miles would do little more than bring London to the latitude of Edinburgh, or Edinburgh to the latitude of London. He must be a sanguine geologist indeed who can expect to account for the glaciation of this country, or for the former absence of ice around the poles by this means. We know perfectly well that since the glacial epoch there have been no changes in the physical geography of the earth sufficient to deflect the pole half a dozen of miles,...