At other times, its waters are comparatively limpid and seem to hold no great amount of mud or fine sand in mechanical suspension; but at high water it contains a large proportion of solid matter, and, according to Lombardini, it annually transports to the shores of the Adriatic not less than 42,760,000 cubic metres, or very nearly 55,000,000 cubic yards, which carries the coast-line out into the sea at the rate of more than 200 feet in a year. [Footnote: This change of coast-line cannot be ascribed to upheaval, for a comparison of the level of old buildings--as, for instance, the church of San Vitale and the tomb of Theodoric at Ravenna--with that of the sea, tends to prove a depression rather than an elevation of their foundations. A computation by a different method makes the deposits at the mouth of the Po 2,123,000 metres less; but as both of them omit the gravel and silt carried down at ordinary and low water, we are safe in assuming the larger quantity.] The depth of the annual deposit is stated at eighteen centimetres, or rather more than seven inches, and it would cover an area of not much less than ninety square miles with a layer of that thickness. The Adige, also, brings every year to the Adriatic many million cubic yards of Alpine detritus, and the contributions of the Brenta from the same source are far from inconsiderable. The Adriatic, however, receives but a small proportion of the soil and rock washed away from the Italian slope of the Alps and the northern declivity of the Apennines by torrents. Nearly the whole of the debris thus removed from the southern face of the Alps between Monte Rosa and the sources of the Adda--a length of watershed [Footnote: Sir John F. W. Herschel (Physical Geography, 137, and elsewhere) spells this word water-sched, because he considers it a translation, or rather an adoption, of the German "Wasser-scheide, separation of the waters, not water-SHED the slope DOWN WHICH the waters run." As a point of historical etymology, it is probable that the word in question was suggested to those who first used it by the German Wasserscheide; but the spelling WATER-SCHED, proposed by Herschel, is objectionable, both because SCH is a combination of letters wholly unknown to modern English orthography, and properly representing no sound recognized in English orthoepy, and for the still better reason that WATER-SHED, in the sense of DIVISION-OF-THE-WATERS, has a legitimate English etymology. The Anglo-Saxon sceadan meant both to separate or divide, and to shade or shelter. It is the root of the English verbs TO SHED and TO SHADE, and in the former meaning is the A. S. equivalent of the German verb scheiden. SHED in Old English had the meaning to SEPARATE or DISTINGUISH. It is so used in the Owl and the Nightingale, v. 107. Palsgrave (Lesclarcissement, etc., p. 717) defines I SHEDE, I departe thinges asonder; and the word still means TO DIVIDE in several English local dialects. Hence, watershed, the division or