Both the diminishing of spatial extension and the breaking up of a whole into parts entail an increase in the quality 'dry'. This applies not only in the sense that the parts which have become independent units are 'dry' in relation to each other - formerly coherent matter being turned into dust - but also in the other sense, and one valid in both cases, that levity and gravity are losing part of their previous inter-connexion. If this twofold process of 'becoming dry' reaches a certain intensity, the substances concerned, provided they are inflammable, begin to burn, with the result that dry heat escapes and dry ash is formed. We note that in each case we are dealing with a change in the relationship between the poles of a polarity of the first order.