On the map published by Prof. Forbes in 1843 the bands are shown crossing the medial moraines of the Mer de Glace; and they are also thus drawn on the map in Johnson's 'Physical Atlas' published in 1849. The text is also in accordance with the map:--"Opposite to the Montanvert, and beyond les Echelets, the curved loops (dirt-bands) extend _across the entire glacier_. They are single, and therefore _cut_ the medial moraine, though at a very slight angle."--'Travels,' p. 166. The italics here belong to Prof. Forbes. In order to help future observers to place this point beyond doubt, I annex, in Fig. 38, a portion of the map of the Mer de Glace taken from the Atlas referred to. If it be compared with Fig. 35 the difference between Prof. Forbes and myself will be clearly seen. The portion of the glacier represented in both diagrams may be viewed from the point near the Flegere already referred to. [Sidenote: ANNUAL "RINGS."] The explanation which I have given involves three considerations:--The transverse breaking of the glacier on the cascade, and the gradual accumulation of the dirt in the hollows between the ridges; the subsequent toning down of the ridges to gentle protuberances which sweep across the glacier; and the collection of the dirt upon the slopes and at the bases of these protuberances. Whether the periods of transverse fracture are annual or not--whether the "wrinkles" correspond to a yearly gush--and whether, consequently, the dirt-bands mark the growth of a glacier as the "annual rings" mark the growth of a tree, I do not know. It is a conjecture well worthy of consideration; but it is only a conjecture, which future observation may either ratify or refute. FOOTNOTES: [A] 'Travels,' page 162. [B] In the large map of Professor Forbes the bearing of the valley is nearly sixty degrees west of the meridian; but this is caused by the true north being drawn on the wrong side of the magnetic north; thus making the declination easterly instead of westerly. In the map in Johnson's 'Physical Atlas' this mistake is corrected. THE VEINED STRUCTURE OF GLACIERS. (27.) [Sidenote: GENERAL APPEARANCE.] The general appearance of the veined structure may be thus briefly described:--The ice of glaciers, especially midway between their mountain-sources and their inferior extremities, is of a whitish hue, caused by the number of small air-bubbles which it contains, and which, no doubt, constitute the residue of the air originally entrapped in the interstices of the snow from which it has been derived. Through the general whitish mass, at some places, innumerable parallel veins of clearer ice are drawn, which usually present a beautiful blue colour, and give the ice a laminated appearance. The cause of the blueness is, that the air-bubbles, distributed so plentifully through the general mass, do not exist in the veins, or only in comparatively small numbers.