According to the recommendation adopted at the third meeting of the International Gravimetric Commission in 1959, a gravity tie measurement between Kyoto, the national fundamental station, and Hakone, one of the most important excenter stations in Japan, was carried out by using three Worden gravimeters in June, 1960. The Hakone station was established recently in order to serve as a terminal station for international gravity connections with gravimeters instead of the national fundamental station. Hakone is located not far from Tokyo and has a close gravity value to that of Kyoto. This station was actually used in two international gravity tie measurements, Japan-Italy, and Japan-Australia, in 1959. The measurement reported here was also made for the purpose of completing these two international ties. Three Worden gravimeters were used for this measurement: No. 60, weich belongs to the Earthquake Research Institute, Tokyo University; No. 127, to the Geological and Mineralogical Institute, Kyoto University; and No. 346, to the Geographical Survey Institute. These gravimeters were set at one station for one night, then transported to the other station by train during the following day. After being observed at the second station for one night, they were brought back immediately to the first station. Three round trips were completed in this way. Thus both stations were occupied three or four times by each gravimeter during eight days. After arriving at each station, a negative drift was observed for every gravimeter. As a result of the laboratory experiments which were made after this measurement, it was concluded that this negative drift was mainly due to the influence of sudden change in temperature. Therefore, those observed values which were affected by this phenomenon were excluded from the computation of the result. In spite of this phenomenon, the drift of the gravimeters, No. 60 and No. 346, was linear in general for the whole period of observations. Regarding No. 127, the drift was negative at first, then showed a gradual change and turned to positive.The computation of the gravity difference was done in the following ways. First, assum-ing that the drift of the gravimeter was linear against time throughout the eight-day observing period, the result A in the following table was obtained by the method of least squares. Second, we took only the transportating hours and by assuming a linear drift for this period, the result B was obtained similarly. Regarding No. 127, quadratic and cubic equations for expressing the drift against time were adopted instead of linear expressions, in both cases of A and B. In the case B, the drift for No. 127 seems to be linear against time for the period of the last two round trips. Consequently, the first two observations were abandoned and a linear drift was assumed for this period and a gravity difference designated by (linear) in the table was computed in the similar way.A Bmgal mgalNo. 60 2.07±0.12 (m.e.) 1.98±0.04 (me.) 127 (quadratic) 2.16±0.11 (, , ) 2.14±0.10 (, , ) (cubic) 2.15±0.09 (, , ) 2.14±0.06 (, , ) (linear) 2.05±0.09 (, , ) 346 1.98±0.05 (, , ) 2.01±0.04 (, , ) Since the gravimeter No. 346 showed a linear drift throughout the long period including this measurement, the first method seems to be reasonable to be adopted. Regarding No. 60, the drift for the period of being set at a station is different from that for transportating hours. The latter was, however, linear and the rate was so constant, that the second method should be adopted. Since the gravimeter No. 127 showed a nonlinear drift, the result obtained from this gravimeter is considered to be less reliable than those obtained from the other two. Considering these values, we get the final result:gHakone-gKyoto=+1.98±0.04(m.e.) mgal.The error in the calibration constants of the gravimeters and those from other sources do not seriously affect

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The second order gravimetric network in Japan is divided into six local nets. A gravity value at each station is determined from the gravity difference observed and adjusted in the net work in which that station is included referring only to the local pendulum station. The net work of the Tohoku district is separated from that of Hokkaido district by sea and there has been no direct gravimetric connection. In June, 1961, a direct tie measurement with gravimeters between Aomori (Asamushi Tidal Station) and Hakodate (Bench Mark No. 6327) was carried out by the members of Geographical Survey Institute in order to connect the two Tohoku and Hokkaido net works. The result is; gB. M.6327 - gAsamushi Tidal Station= + 17.24±0.04 mgal Some discussions about the drift and scale value of the used gravimeters are given and the comparison of Tohoku net work with that in Hokkaido is made.

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The vertical movements of the land around the Bay of Ise are discussed not only by using the results of the precise levellings during 75 years from 1.885 to 1960, but also by the data of sea levels at mareograph stations. The yearly changes of land levels are of the order of centimeter and the greater part of the land in this region tends to subside. The rate of subsidence seems to increase with year. The largest amount of subsidence since 1885 is found to be in the area between the rivers of Kiso and Nikko, i.e. B.M. 1473, whereas the largest rate of subsidence during recent years is not appeared at B.M. 1473 but B.M. 1474-1475 and B.M. 1470. Further, the secondary variation of vertical land movements takes an undulatory form. This secondary undulatory movement is overlapping to the foundamental subsidence. The vertical earth movements are related to the geologic structure in this area.

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