We recall the fact that the whole Solfatara phenomenon had its origin in a flame being swayed over one of the fango holes. Although it remains true that the suction arising from the diminished air pressure over the hole cannot account for the intense increase of ebullition in the hole itself, not to speak of the participation of the entire region in this increase, there is the fact that the whole event starts with a suctional effect. As we shall see in the next chapter, any local production of heat interferes with the gravity conditions at that spot by shifting the balance to the side of levity. That the response in a place like the Solfatara is what we have seen it to be, is the result of an extraordinary lability of the equilibrium between gravity and levity, a characteristic appertaining to the earth's volcanism in general. For the people living near the Solfatara it is indeed common knowledge that there are times when this lability is so great that the slightest local disturbance of the kind we have described can provoke destructive eruptions of great masses of subterranean mud. (At such times access to the Solfatara is prohibited.) We shall understand such an eruption rightly if we picture it as the counter-pole of an avalanche. The latter may be brought about by a fragment of matter on a snow-covered mountain, perhaps a little stone, breaking loose and in its descent bringing ever-accumulating masses of snow down with it. The levity-process polar to this demonstration of gravity is the production of a mightily growing 'negative avalanche' by comparatively weak local suction, caused by a small flame. * Earlier in this chapter (page 150) we said that if we want to understand how spirit moves, forms and transforms matter, we must recognize the existence of non-mechanical (magical) causes of physical effects. We have now found that the appearance of such effects in nature is due to the operations of a particular force, levity, polar to gravity. Observation of a number of natural happenings has helped us to become familiar in a preliminary way with the character of this force. Although these happenings were all physical in appearance, they showed certain definitely non-physical features, particularly through their peculiar relationship to three-dimensional space. More characteristics of this kind will appear in the following pages.