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 |
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ablation Alps analogy angle annual motion appears Arveiron August Balmat bands breadth cause centre congelation convex Courmayeur crevasses curve direction dirt-bands distance Edinburgh effect Elie de Beaumont Etna evidence experiment fact feet fissures fluid friction frontal dip Glace of Chamouni glacie Glacier des Bois Glacier des Bossons Glacier du Géant glacier motion glacier moves Grindelwald horizontal hydrostatic pressure inches inclination internal July lava stream less Letter on Glaciers longitudinal lower marked mass Mean daily motion Mer de Glace millimetres Mont Blanc Montanvert moraine motion of glaciers movement nearly névé observations origin parallel particles Philosophical Journal plane plastic Plate portion produce retardation rock Saussure Saussure's season semifluid sides sliding slope snow solid station summer surface Talefre temperature thawing theodolite THEORY OF GLACIER tion transverse Travels valley veined structure velocity vertical Vesuvius VISCOUS THEORY volume whilst winter
Popular passages
Page 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.
Page 222 - 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...
Page 225 - ... 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.
Page 245 - 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.
Page 224 - ... 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°.
Page 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...
Page 225 - 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.
Page 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...
Page 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
Page 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...