Comentarios de la gente - Escribir un comentario
No encontramos ningún comentario en los lugares habituales.
Otras ediciones - Ver todas
according actually amount appears arctic assume Atlantic become beds bottom boulder clay cause circulation climate cold column conclusion condition consequently consider considerable continue course covered deposits depth descend difference direction earth's eccentricity effect entire equal equator equatorial evidence existence extent fact feet flow follows foot force geological glacial epoch glacier globe gravity greater Gulf-stream heat hemisphere icebergs increase influence land latitude less lower mass matter mean miles molecules motion move North northern observed ocean orbit pass period physical polar polar regions poles portion present pressure probably produce Professor quantity question radiation raise reached reason received reference regard regions remains represent result rise river rocks sand says seen slope snow southern stream summer supposed surface temperature tend theory thickness things true warm weight whole winds winter
Página 332 - I look at the geological record as a history of the world imperfectly kept, and written in a changing dialect ; of this history we possess the last volume alone, relating only to two or three countries. Of this volume, only here and there a short chapter has been preserved ; and of each page, only here and there a few lines.
Página 224 - Let us imagine the eccentricity to be at its superior limit, '07775, and the winter solstice in the aphelion. The midwinter temperature, owing to the increased distance of the sun, would be lowered enormously; and the effect of this would be to cause all the moisture which now falls as rain during winter in temperate regions to fall as snow. Nor is this all ; the winters would not merely be colder than now, but they would also be much longer. At present the summer half year exceeds the winter half...
Página 319 - ... been 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...
Página 367 - We had completely sunk the strip of land between the Mer de Glace and the sea, and no object met the eye but our feeble tent, which bent to the storm. Fitful clouds swept over the face of the full-orbed moon, which, descending towards the horizon, glimmered through the drifting snow that scudded over the icy plain — to the eye in undulating lines of downy softness, to the flesh in showers of piercing darts.
Página 101 - It is not necessary to associate with oceanic currents the idea that they must of necessity, as on land, run from a higher to a lower level. So far from this being the case, some currents of the sea actually run up hill, while others run on a level. The Gulf Stream was of the first class.
Página 59 - Perfectly dry air seems to be nearly incapable of absorbing radiant heat. The entire radiation passes through it almost without any sensible absorption. Consequently the pitch on the side of the ship may be melted, or the bulb of the thermometer raised to a high temperature by the direct rays of the sun, while the surrounding air remains intensely cold. " A joint of meat," says Professor Tyndall, " might be roasted before a fire, the air around the joint being cold as ice"J.
Página 31 - ... that, of all places, here ought to be placed the substance best adapted for preventing the dissipation of the earth's heat into space, in order to raise the general temperature of the earth. Water, of all substances in nature, seems to possess this quality to the greatest extent; and, besides, it is a fluid, and therefore adapted by means of currents to carry the heat which it receives from the sun to every region of the globe*.
Página 367 - The walk to it was richly rewarded by an uncommonly extensive view, which showed us that the inland ice continued constantly to rise towards the interior, so that the horizon towards the east, north, and south was terminated by an ice-border almost as smooth as that of the ocean.
Página 499 - This proves that every molecule resumes its crystalline form the moment after the energy is transferred over to the adjoining molecule. This point being established, every difficulty regarding the descent of the glacier entirely disappears; for a molecule the moment that it assumes the fluid state is completely freed from shearing-force, and can descend by virtue of its own weight without any impediment. All that the molecule requires is simply room or space to advance in.
Página 27 - There is actually, therefore, nearly as much heat transferred from the tropical regions by the Gulf-stream as is received from the sun by the entire arctic regions ; the quantity conveyed by the stream to that received from the sun by those regions being as 15 to 18. But we have been assuming in our calculations that the percentage of heat absorbed by the atmosphere is no greater in polar regions than it is at the equator, which is not the case. If we make due allowance for the extra amount absorbed...