This structure, which appears to have escaped the notice of authors on the subject, is a veined or ribboned appearance which pervades the whole ice of many glaciers. The veins or bands are occasioned by the alternation of ice more or less compact; that which is porous approaching to white or whitish green, the denser ice having a bluish tint. The thickness varies from a fraction of an inch to several inches, and the parallelism may be considered as complete through considerable spaces. It extends in more or less complete development from the névé, or uncompacted glacier, down to the inferior termination; and during the greater part of this space, in the case of the lower glacier of the Aar, the bands were parallel to the lofty walls by which the glacier was bounded laterally; their position was generally vertical, but sloping from below upwards and outwards as the distance from the sides of the glacier diminished.