Occasional papers on the theory of glaciers: now first collected and chronologically arranged, with a prefatory note on the recent progress and present aspect of the theory
Adam and Charles Black, 1859 - 278 páginas
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Occasional Papers on the Theory of Glaciers: Now First Collected and ...
James D. Forbes
Sin vista previa disponible - 2018
Alps analogy angle annual motion appears Arveiron August Balmat bands Bishop of Annecy breadth cause centre compact considerable continuity convex crevasses curve curved bands daily motion declivity direction dirt-bands dislocation distance Edinburgh effect Elie de Beaumont Etna evidence experiment explained fact feet fissures fluid fluidity friction frontal dip Geant Glace of Chamouni Glacier des Bois glacier motion glacier moves glacier of Bossons Grindelwald hydrostatic pressure inches inclination internal lava stream less Letter on Glaciers longitudinal lower marked mass measurement millimetres Mont Blanc Montanvert moraine Motion of Glaciers movement nearly observations origin parallel particles Philosophical Journal plastic Plate portion produce remarkable resistance retardation rock Saussure Saussure's season sides sliding slope snow solid station summer surface temperature thawing theodolite theory of glaciers tion transverse Travels valley veined structure velocity vertical Vesuvius viscous theory volume weather whilst winter
Página 9 - They appear to me only resolvable, on the supposition that crystalline or polar forces acted on the whole mass simultaneously, in given directions, and with adequate power.
Página 226 - Faraday's chief fact, to which the term 'regelation ' has been more lately applied, is this : that pieces of ice, in a medium above 32°, when closely applied, freeze together, and flannel adheres apparently by congelation to ice under the same circumstances. "1. These observations I have confirmed. But I have also found that metals become frozen to ice when they are surrounded by it, or when they are otherwise prevented from transmitting heat too abundantly. Thus, a pile of shillings being laid...
Página 229 - ... surface cannot afford warmth enough to keep the water liquid. " This effect is well seen by the instant freezing of a piece of ice to a worsted glove even when on a warm hand. But metals may act so, provided they are prevented from conveying heat by surrounding them with ice. Thus, as has been shown, metals adhere to melting ice.
Página 249 - A GLACIER is AN IMPERFECT FLUID, OR A VISCOUS BODY. WHICH IS URGED DOWN SLOPES OF A CERTAIN INCLINATION BY THE MUTUAL PRESSURE OF ITS PARTS.
Página 228 - ... what is called 32°. But I have not yet had an opportunity of verifying the conjecture. [My idea is, that the invasion of cold from the surrounding ice is spent in producing a very gradual ' regelation ' in the water which touches the ice, leaving the interior water in possession of its full dose of latent heat, and also of a temperature •which may slightly exceed 32°.
Página 42 - Geant, perhaps even better marked. As the lower glacier of Grindelwald furnished an excellent example of all the modifications which I have elsewhere shown to belong to the canal-shaped glacier, with branches ; so the upper glacier is an exact representative, in its lower part, of the oval glacier, for which I have taken that of the Rhone as a type ; whilst many of the tributary glaciers of Grindelwald and the Jungfrau bear ample testimony to the general fact, that the structure of glaciers is developed...
Página 229 - This waste has yet to be proved ; but I have little doubt of it ; and it is confirmed by the wasting action of superficial streams on the ice of glaciers, though other circumstances may also contribute to this effect. III. The theory explains ' regelation.' For let a second plane surface of ice A'B' be brought up to nearly physical contact with the first surface AB.
Página xvi - ... that the reconsolidation of the bruised glacial substance into a coherent whole may be effected by pressure alone acting upon granular snow or upon ice softened by imminent thaw into a condition more plastic than ice of low temperature, and that the terms ' bruising and re-attachment,' ' incipient fissures reunited by time and cohesion...
Página 29 - ... at the very same points; the fissures, though forming very different angles with the axis or sides of the glacier at different points of its length, opposite the same point are always similarly disposed, — the same parts of the glacier, relatively to fixed rocks, are every year passable, and the same parts are traversed by innumerable fissures. Yet the solid ice of one year is the fissured ice of the next, and the very ice which this year forms the walls of a
Página 22 - Fig. 5. ture equally, as there are some glaciers which possess the structure itself more developed than others. The cause of the dazzling whiteness of the Glacier des Bossons at Chamouni is the comparative absence of these layers of granular and compact ice ; the whole is nearly of uniform consistence, the particles of rock scarcely find a lodgment, the whole is washed clean by every shower. The superficial bands are well seen on the Mer...