Of the strictly material elements of the universe, the most important is _moisture_ or _water_. It is moisture which gives concreteness and therefore weight to things. Nothing has weight which has not been formed into one by the union of innumerable parts under the action of water.[350] Consistently with this, Bruno believed the heaviest bodies, as the metals, to be the most solid and concrete, and therefore to contain most moisture. It is moisture also which, penetrating through the arteries, veins, and bones of the earth, gives to it both variety of aspect and the power of life. The visible moisture on the earth's surface, the seas and lakes, is a mere nothing as compared to that which is diffused through its interior--is but the sweat, as it were, of the earth's body.[351] Bruno's passion for homogeneity led him to understand that in its surface the land under the sea is similar to that above it, with which the former is continually changing place, and it is divided up into plains, mountains, valleys, the islands and rocks of the sea being the tops of the mountains:--a remarkable intuition of the truth, however arrived at. As to the familiar elements, _earth_ and _fire_, Bruno could neither allow a special place or sphere nor a special direction of movement to either, as in the Aristotelian cosmology. The earth was not the centre of the universe, and there were earths or similar planets everywhere. To the several arguments of the Peripatetics[352] for the centrality of the earth,--from the heaviness, the darkness, solidity, composite character of the earth's matter, and the movements of its parts, from the idea that contraries shun one another so that the coldest element, for example, should be in the centre, the hottest at the extreme,--Bruno opposed the common-sense answers that his own theory suggested to him. His appeal was always from "fictitious order" to the evidence of "sense and reason." The argument has no longer any interest in itself, and to pursue it into detail would hardly be edifying; but so full is it, so weighty and so vigorous, that one wonders how even the "Peripatetics" failed to be convinced by it. Bruno's very errors are interesting. Fire for example, far from being the outermost, lightest, subtlest element, was regarded by him as a body of which the substance, (light and heat being _accidents_) was water mixed with earth;[353] and in general, he maintained, no element was ever found in isolation. As to the supposed coldness of the central element,--the earth,--he believed, again anticipating future discoveries, that the centre of the earth was not cold, but hot, the source of terrestrial warmth; but the theory loses something of its value, scientifically, from the imagined _vitality_ of the planet, by which it is supported.[354] It was natural that the _coincidence of contraries_ should be brought to do duty against the maxim on which the Aristotelian view was really