If the foregoing reasoning is correct, the great and especially the sudden departures from the smooth gyroscopic circle described by the pole in the Eulerian motion would be expected to occur at about the same time as unusual earthquake activity. This brings us to an interesting inquiry carried out by Milne[137] and amplified by Knott.[138] Taking Albrecht's representation of the irregular spiral-like motion of the pole, as given in Fig. 13, they show that there is a preponderance of severe earthquakes at times when the direction of motion of the earth in reference to its axis departs from the smooth Eulerian curve. A summary of their results is given in Table 9. The table indicates that during the period from 1892 to 1905 there were nine different times when the curve of Fig. 13 changed its direction or was deflected by less than 10 deg. during a tenth of a year. In other words, during those periods it did not curve as much as it ought according to the Eulerian movement. At such times there were 179 world-shaking earthquakes, or an average of about 19.9 per tenth of a year. According to the other lines of Table 9, in thirty-two cases the deflection during a tenth of a year was between 10 deg. and 25 deg., while in fifty-six cases it was from 25 deg. to 40 deg.. During these periods the curve remained close to the Eulerian path and the world-shaking earthquakes averaged only 8.2 and 12.9. Then, when the deflection was high, that is, when meteorological conditions threw the earth far out of its Eulerian course, the earthquakes were again numerous, the number rising to 23.4 when the deflection amounted to more than 55 deg.. TABLE 9 DEFLECTION OF PATH OF POLE COMPARED WITH EARTHQUAKES _No. of _No. of _Average No. _Deflection_ Deflections_ Earthquakes_ of Earthquakes_ 0-10 deg. 9 179 19.9 10-25 deg. 32 263 8.2 25-40 deg. 56 722 12.9 40-55 deg. 19 366 19.3 over 55 deg. 7 164 23.4