Depending on the role played in the overall water balance of the water body by the water influx in the given branch (river), the level of this body will either be reduced accordingly and the water will become brackish, or else it will dry up completely, leaving a salt depression. The water table in the part of the valley through which the southern branch flows, on the other hand, will be raised, since the infiltration losses there will be diminished. Accordingly, the amount of water and the stream velocity in this branch will increase, and downcutting of the channel bed will begin. Thus, the direction of the river will have a tendency to shift toward the equator. Obviously, if the diurnal rotation of the Earth slows down, the northern and southern branches of the river will exchange roles, and the direction of the river will be shifted poleward.
At this point we should note the following. Fluctuations in the amount of solid suspended matter carried out by the continental water in the directions of the pole and the equator are caused by the irregularity of the Earth's rotation. However, just as in the case of the shifting of water masses in these directions, there will be a reverse effect on the diurnal rotation velocity as well. Thus, when the rotation slows down, the pole ward transfer of masses of sedimentary rock will increase, causing a decrease in the moment of inertia and a corresponding rise in the diurnal rotation velocity. An increase in the diurnal velocity, on the other hand, leads to a greater transfer of sedimentary masses toward the equator; thus, the moment of inertia increases and the velocity is reduced accordingly. The effect (on the diurnal-rotation velocity) of a fluctuation in the amount of sedimentary rock transported meridionally by the continental water, as a result of irregularity of the diurnal rotation, can thus be summed up as follows: it is as if a gigantic inertial flywheel were operating, which tends to reduce the angular velocity of the Earth when it increases and to accelerate the rotation when it slows down.
Inconstancy of the magnitude of the centrifugal diurnal-rotation forces is one of the main factors responsible for the formation of vast alluvial plains on the Earth's surface. During epochs in which the climate is cooler, the angular velocity of the Earth increases as a result of the formation, predominantly in the high latitudes, of ice; consequently, during these epochs the directions of surface-water flows have a tendency to shift toward the equator. The southern parts of plains will become wetter, and depressions in them will be filled in more intensively with solid deposits than is the case for the northern parts. During these periods aeolian processes develop extensively in the northern parts of plains, particularly under arid conditions.
During epochs of warmer climate, the diurnal-rotation velocity decreases as a result of the transformation of ice into liquid water and the transference of much of the water to the low latitudes. The processes taking place in the southern and northern parts of plains will then be the opposite of those described above. Consequently, the centrifugal forces of the Earth, which vary periodically in magnitude, alter the directions of the water flows, shifting them from the southern parts of plains to the northern parts and vice versa. Operating in conjunction with wind forces, they level off plains and make them more or less horizontal, producing the corresponding microrelief.
Periodic rearrangements of the drainage system on a planet-wide scale are thus caused by axial pulsations of the entire hydrosphere relative to the lithosphere, as a result of variations in the rotational regime of the Earth. Let us call these rearrangements the third- order re g u 1 a rity in the evolution of the Earth.* In addition to the three main factors (climate, diurnal-rotation regime, and tectonics), there are many other things which affect the evolution of the Earth, and they may be either terrestrial or extraterrestrial in origin. Table 1 shows the general scheme of the interactions between the main factors. The large circle in the middle (1), with the three smaller circles (2, 3, and 4) around it, represents the first-order regularity in the evolution of the Earth (the relation-interaction between the three main factors: climate, diurnal-rotation regime, and tectonics). The three main factors interact in such a way that any change in one of the factors, no matter what its cause (see squares 5, 6, 7, and 8), must give rise to corresponding changes in each of the others.
The interaction between the three main factors is effected by means of periodic redistributions of the water masses on the Earth's surface, the ultimate cause of the interaction being the thermal energy of the Sun (see square 9). Periodic variations in the diurnal-rotation regime of the Earth give rise to out-of-phase pulsations of the geospheres (atmosphere, hydrosphere, and lithosphere). We have called this "triple pulsation" of the geospheres the second-order regularity in the evolution of the Earth (see circle 10). The out-of-phase pulsation of the hydrosphere and lithos phere leads to periodic rearrangements of the drainage system on a planet wide scale, a phenomenon which we have designated as the third-order regularity in the evolution of the Earth (see circle 11). Local factors may also influence the rearrangement of the drainage system (see square 12).