A sequence of stages of generation, upward transfer, differentiation, and solidification of magmas is studied in its physical aspects. It is assumed that the parental basaltic magmas are generated at a few hundred kilometers depths from the surface during some stages of terrestrial evolution. The generation of magmas is considered as the cause of tectonic activity within the crust and the upper mantle. A stability of molten layer under various physical conditions is studied. If the rate of convection W within magmas is smaller than 0.01cm/year the magmas degenerate in situ. On the contrary they are transferred toward surface reserving their mass for W 〓 1cm/year. For W～0.1cm/year the molten layeres are floating upward with decreasing mass-and disappear at some depths. It might have a connection with the low velocity layer confirmed in seismology. When the initial thickness of magmas is greater than 200km, they approach the surface even for W～0.1cm/year. Differentiation of magmas accompanted solidification is also studied. An albite-anorthite binary model is supposed and variations in temperature inside and outside the magma reservoir is calculated. A life of sheet magma of which thickness is 1km is nearly a hundred thousand years when it is situated at depths from the surface of the earth. A life is reduced to half when situated close to the surface. The average solidification rate is of the order of cm/year.

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Contents of nitrogen and oxygen gases in about three hundred hot-spring waters were measured. The nitrogen is rich in the springs of low and moderate temperature and poor in those of high temperature. The relation between the flow temperatures and the nitrogen contents differs from the Winkler’s solubility curve, that is, supersaturation predominates at low and moderate temperature, and unsaturation at high temperature. The magmatic water which may be contained in hot-spring water does not play an important role to make such temperature-nitrogen relation. Oxygen contents are little in every spring and the oxygen consumption under the ground may have contributed to make oxygen-poor waters. Some examples of geographical distribution of the nitrogen and the oxygen consumption are shown for some spas, suggesting the flow direction of hot-spring water and the relation with the usual ground-water. Annual and daily variations of the nitrogen and oxygen contents in hot-spring water are discussed together with the variations of other physical and chemical factors of the springs.

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