Another circumstance to which navigators have not adverted, which corroborates the opinion here stated, is, that, in depths so great as those to which we allude, the sea, always agitated at the surface, breaks with force upon these reefs, without requiring for that purpose any additional impulse from the winds. And by merely attending to the necessary consequences of the observations of these same navigators, who say (what is very true) that, wherever the waves are agitated, the lithophytes are unable to go on with their work, because they destroy their frail edifices, we shall acquire the moral certainty that these submarine steeps are not produced by these animalcules. But, in these same places, let there occur a hollow, a sheltered spot of some kind, and then they will immediately raise their habitations, and will contribute to diminish the little depth that already exists there. And this is what may be seen in almost all the places where an elevated temperature permits these animals to grow in abundance. In the localities where the tides are sensible, their currents alone may sometimes form irregular canals between the madrepores, without their ever being encumbered with their species, from the twofold cause united, of the motion and the coldness of the water; while, on the other hand, the flexible alcyonia are seen to multiply there. When these geological dispositions are carefully observed, we see that the zoophytes rise to the surface of the waves, never beyond it; after which the generation which has attained thus far appears to die. It is destroyed much sooner, if, from the effect of the tides, these frail animalcules are exposed naked to the action of a burning sun. When there occur small hollows in these heaps of inert spoils, deprived of their inhabitants, which are always covered by the water, several tufts of those lithophytes are still remarked, which, having escaped from the almost general destruction, glow with the most lively colours. Then, the families which are developed anew, not being able to build on the outside of those reefs on which the sea is constantly breaking, draw nearer and nearer the shore, where the waves now deadened have scarcely any more action upon them, as in the Isle of France, at Timor, the Papua, the Marian, and the Sandwich Islands; provided always the waters had not a great depth, as is the case at Turtle Island, of which Cook speaks, where no bottom is found between the madrepore reefs and the island, notwithstanding the shortness of the space which exists between these two points. If we examine these animals in the places best adapted to their growth, we shall see their different species, the forms of which, as varied as they are elegant, become rounded into balls, spread out into fans, or ramify into trees, mingling together, blending with each other, and reflecting the varied hues of red, yellow, blue and violet.