And of the moon the same. The moon has her back to us for ever. Not her face, as we like to think. The moon also pulls the water, as the sun does. But not in evaporation. The moon pulls by the magnetic force we call gravitation. Gravitation not being quite such a Newtonian simple apple as we are accustomed to find it, we are perhaps farther off from understanding the tides of the ocean than we were before the fruit of the tree fell to Sir Isaac’s head. It is certainly not simple little-things tumble-towards-big-things gravitation. In the moon’s pull there is peculiar, quite special force exerted over those water-born substances, phosphorus, salt, and lime. The dynamic energy of salt water is something quite different from that of fresh water. And it is this dynamic energy which the sea gives off, and which connects it with the moon.