The universe to Bruno is transfused with spirit, soul or life, "the soul of the universe," which animates its every part. "The seat or place of God is the universe, everywhere the whole immeasurable heaven, empty space, of which He is the fulness." The material aspect, or, as Bruno sometimes seems to say, the _body_ of this spirit is the ether, a subtle fluid distinguished from the air we breathe by the absence of moisture. The ether is a purely passive, non-resisting medium, permeating the universe, without quality, and unimpressionable by force or action; thus it is penetrated by the heat of any radiating body without diminishing its force. It took the place, for Bruno, of the mythical Fifth Essence, which had so long fed the dreams of philosophers--"Divine yet corporeal, material yet without matter, a form without privation, conjoining act with potency, neither heavy nor light, suffering neither generation, nor corruption, nor alteration, neither increase nor decrease; beyond which no sensible existence is, first-born and creatrix of Nature, simplest of beings, all-containing, most powerful, most active, most living, most perfect of existences, endowed with life and intelligence, of its own nature moving circularly, etc., etc.--all this is at length proved to have been a most portentous shadow without body."[347] Heaven is either empty space, or it is an ethereal substance, "a very subtle kind of air, which is the first and most universal occupant of space."[348] Again, the ether is described as a vapour or smoke, a nebulous matter, penetrating throughout the depths of the void, interpenetrating all things and embracing all; as not entering into movement of its own accord, for it is but an exhalation of the wind--a kind of continuous vapour such as is contained in the bowels of the earth: in it is neither heat nor cold nor any similar effect (_passio_), but it is the medium through which these are borne. All these require moisture: moisture alone can "fix" light or darkness or combine atoms into a concrete body and prevent their random flight through the air.[349] It has been claimed that in this and other passages Bruno anticipated the modern theory of the ether; it must be noted, however, that he expressly denies to its parts any kind of motion--it is only the composite body which moves--and that he speaks of this heaven or ether as the soul which is at once immanent in and comprehends the stars, _i.e._ as the soul of the universe. [Sidenote: Moisture.] [Sidenote: Earth: Fire.]