Most of the lines of direction, when plotted on the map, converge towards an area lying between the meridians of Oneglia and San Remo, and between nine and fifteen miles from the coast. For places near the epicentre, the most trustworthy, in Mercalli's opinion, are those made at Oneglia, Mentone, Taggia, Bordighera, Castel Vittorio, Nice, and Genoa; and the points in which these lines Intersect one another are Indicated by small crosses on the map of the meizoseismal area (Fig. 34). All of them lie at sea at distances between six and fifteen miles to the south of Oneglia. The most probable position of the principal epicentre is that marked by the small circle A, which is situated about fifteen miles south of Oneglia. [Illustration: FIG. 34.--Meizoseismal area of the Riviera earthquake. (_Taramelli and Mercalli._)] There are, however, several lines of direction which can have no connection with this epicentre. Besides the east and west lines at Nice, Mentone, and Antibes, there are others at the same places which run north and south or nearly so. Professor Mercalli believes that they were due to vibrations coming from a second focus lying to the south of Nice, and there are also several lines of direction at more distant places which converge towards the neighbourhood of the corresponding epicentre. This conclusion receives unexpected support from some of the best time-records. At the railway-stations of Loano and Pietra Ligure, the times of occurrence were given as 6h. 20m. 5s. and 6h. 20m. respectively--estimates which are probably accurate to within a few seconds; for, at the moment of the shock, the officer who brought the exact time along the railway-line from Genoa was at Loana, and had just passed through Pietra Ligure. On the other hand, the estimates for Mentone and Nice--namely, 6h. 18m. 35s. and 6h. 19m. 43s., if not equally exact, cannot err by many seconds, certainly not by so much as one minute. Since the distances of Loana and Pietra Ligure from the principal epicentre are 31 and 32 miles, and those of Mentone and Nice 28 and 37 miles, it is therefore clear that the vibrations which arrived first at Nice and Mentone must have come from a local focus, where the impulse preceded that at the principal focus by several seconds. DEPTH OF THE PRINCIPAL FOCUS. Inaccurate as are all the methods of determining the depth of focus, it seems probable, as Professor Issel argues, that the principal Riviera focus was situated at a considerable distance from the surface. In no part of the meizoseismal area was the shock a really violent one; yet its intensity must have faded very slowly outwards, for it was strong enough to stop clocks at places in Switzerland and elsewhere not less than 250 miles from the origin.