20. 334

Papers presented to the Royal Society by Professor Forbes in 1846; Capillary Hypothesis of glacier motion; hypothesis examined

21.—Thomson's Theory. 340

Statement of theory; influence of Pressure on the Melting Point of Ice; difficulties of theory; Calculation of requisite Pressure; Actual pressure insufficient

22.—Pressure Theory. 346

Pressure and Tension; possible experiments; Ice may be moulded into Vases and Statuettes or coiled into Knots; this no proof of Viscosity; Actual Experiments; a sphere of ice moulded to a lens; a lens moulded to a cylinder; a lump of ice moulded to a cup; straight bars of ice bent; ice thus moulded incapable of being sensibly stretched; when Tension is substituted for Pressure, analogy with viscous body breaks down

23.—Regelation.351

Faraday's first experiments; Freezing together of pieces of ice at 32°; Freezing in Hot Water; Faraday's recent experiments; Regelation not due to Pressure nor to Capillary Attraction; it takes place in vacuo; fracture and regelation; no viscidity discovered

24.—Crystallization and Internal Liquefaction. 353

How crystals are 'nursed;' Snow-Crystals; Crystal Stars formed in Water; Arrangement of Atoms of Lake Ice; dissection of ice by a sunbeam; Liquid Flowers formed in ice; associated Vacuous Spots; curious sounds; their explanation; Cohesion of water when free from air; liquid snaps like a broken spring; Ebullition converted into Explosion; noise of crepitation; Water-cells in glacier ice; Vacuous Spots mistaken for Bubbles; not Flattened by Pressure; experiments; Cause of Regelation

25.—The Moulins. 362

Their character; Depth of Moulin on Grindelwald Glacier; Explanation the Grand Moulin of the Mer de Glace; Motion of moulins

26.—Dirt-Bands of the Mer de Glace.367

Their discovery by Professor Forbes; view of Bands from a point near the Flégère; Bands as seen from Les Charmoz; Skew Surface of glacier; aspect of Bands from the Cleft Station; Origin of bands; tendency to become straight; differences between observers

27.—Veined Structure of Glaciers.376

General appearance; Grooves upon the glacier; first observations; description by M. Guyot; observations of Professor Forbes; Structure and Stratification; subject examined; Marginal Structure; Transverse Structure; Longitudinal Structure; experimental illustrations; the Structure Complementary to the Crevasses; glaciers of the Oberland, Valais, and Savoy examined with reference to this question

28.—The Veined Structure and Differential Motion.395

Marginal Structure Oblique to sides; Drag towards the centre; difficulties of theory which ascribes the structure to Differential Sliding; it persists across the lines of maximum sliding

29.—The Ripple Theory of the Veined Structure. 398

Ripples in Water supposed to correspond to Glacier Structure; analysis of theory; observation of the MM. Weber; water dropping from an oar; stream cleft by an obstacle; Two Divergent lines of Ripple; Single Line produced by Lateral Obstacle; Direction of ripples compounded of River's motion and Wave motion; Structure and Ripples due to different causes; their positions also different

30.—The Veined Structure and Pressure. 404

Supposed case of pressed prism of glass; Experiments of Nature; Quartz-pebbles flattened and indented; Pressure would produce Lamination; Tangential Action

31.—The Veined Structure and