This fact constitutes a very strong objection to the tectonic theory of earthquakes, and thus the very depths of the earth speak against it. We have already mentioned that K. von Seebach estimated the depth of the earthquake focus from the movements of the waves, and found it not very great. But his estimates, as Prof. August Schmidt has shown, rest upon physically incorrect premises; according to Schmidt's more correct calculation, the center of the Charleston earthquake of 1886 lay at a depth of one hundred and twenty kilometres, where there can be no question of tectonic movements, because general fluidity is reached at one hundred kilometres. Further, the earthquake at Lisbon, if the tectonic theory is valid, might, taking the character of the region into consideration, have been occasioned by a slide. But how large must the plunging mass, how deep the plunge or slide have been to produce such shocks as destroyed Lisbon and shook Europe to beyond Bohemia! Where can we find room in the closely compressed interior of the earth for such irruptions? Even if such a sudden sinking had left no trace in the interior, it should have left its marks on the surface. Mr. John Milne counts up not less than 8,331 considerable earthquake shocks in Japan between 1885 and 1892; Julius Schmidt, former director of the observatory in Athens, enumerated three hundred severe and dangerous and fifty thousand light shocks for Phocis alone between 1870 and 1873, of which not a trace of land changes or depressions can be perceived, aside from superficial avalanches (on Parnassus, for example) and subsidence of meadows and other spongy soil, like the famous depression of the Molo at Lisbon.