Exactly the same thing holds good for the sequence of physical states of matter which we are considering here. Observation of this sequence with the bodily eyes alone will show nothing but a reduction of the specific gravity of the material concerned. He who is at pains to observe also with the eye of the spirit, however, is aware of a positive increase of lightness going hand in hand with a decrease of heaviness. Regarded thus, the three ponderable conditions form what Goethe would have called a 'spiritual ladder'. As 'rungs' of such a ladder they clearly point to a fourth rung - that is, a fourth state in which levity so far prevails over gravity that the substance no longer has any weight at all. This picture of the fourfold transformation of matter calls for an inquiry into the transition between the third and fourth states, corresponding to the well-known transitions between the