From this, and from the fact that it is found that a number of different pendulums differently situated on the same area give similar evidence of these movements, it would hardly seem that these phenomena could be attributed to causes like changes in temperature and moisture. M. S. di Rossi lays stress on this point, especially in connection with his microseismograph, where there are a number of pendulums of unequal length which give indications of a like character. The direction in which these tips of the soil take place—which phenomena are noticeable in seismic as well as microseismic motions—Rossi states are related to the direction of certain lines of faulting. _Indications of levels._—Bubbles of delicate levels can be easily seen to change their position with meteorological variations; but Rossi also tells us that they change their position, sometimes not to return for a long time, during a microseismic storm. Here again we have another phenomenon pointing to the fact that microseismic disturbances are the companions of slow alterations in level. One of the most patient observers of levels has been M. Plantamour, who commenced his observations in 1878, at Sécheron, on the Lake of Geneva. He used two levels, one placed north and south, and the other east and west. During the summer of 1878 the east end rose, but at the end of September a depression set in. The diurnal movements had their maximum and minimum at 6 and 7.45 A.M. and P.M. The total amplitude was 4·89″. The variations of the east and west level appeared to be due to the temperature, but the movements of the north and south level were dependent upon an unknown cause. Between October 1, 1879, and September 30, 1880, the east end fell rapidly, from the middle of November up to December 26, amounting to 88·71″. It then rose 6·55″ to January 5, and then fell again. On January 28 it reached 89·95″, after which it rose. Between October 4, 1879, and January 28, 1880, the movement was 95·8″, against 28·08″ of the previous year. These movements were not due alone to temperature. The north and south level, which was not influenced by the cold of the winter, moved 4·56″. In the previous year 4·89″.[144] From February 17 to June 5, 1883, the author observed in Tokio the bubbles of two delicate levels, one placed north and south, and the other east and west. They were placed under glass cases on the head of a stone column. The column, which is inside a brick building, rests on a concrete foundation, and is about ten years old. It is in no way connected with the building. The temperature of the room has a daily variation of about 1° Fahr. In both these levels diurnal changes are very marked. Occasionally they are enormously great. Thus, on March 25, the readings of the south end of the north south level were as follows:—