ABSTRACT
If panicles of water, also of mass m, are to remain in position at points P, and P2 they must also be acted upon by forces F towards their centres of rotation G~ and G2. The attraction of the Moon on these particles is respectively F~ which is less than F, and F~ which is greater than F since P~C~ and P~C~ are respectively greater and less than L. The vector differences shown in the figure F minus F,, and F 2 minus F, are the tideraising forces. The vertical components of these forces are small in relation to the Earth's gravity and are of little importance; the horizontal components which are towards A and B, respectively, generate the tidal wave. They are zero at points A and B in line with the Moon and near points O and P at fight angles to AB, and are a maximum midway between these points. Their directions, indicated by the circumferential arrows in the figure, cause two high waters, one directly under the Moon and the other on the opposite side of the Earth.
