The Vipassana Dipani
The Manual of Insight
Or Material Quality Of Limitation
Akasa-dhatu means the element of space. In a heap of sand there is a space between each particle of sand. Hence we may say that there are as many spaces as there are particles of sand in the heap; and we can also distinguish the particles of sand from one another. When the heap is destroyed the particles of sand are scattered about, and the space enclosed between them disappears also. Similarly, in very hard lumps of stone, marble, iron, and metal, there are innumerable atoms and particles of atoms, which are called kalpas or groups. Into every finest, smallest particle of an atom there enters at least these following eight qualities of matter, i.e., the Four Essentials and color, odor, savor, and nutritive essence. And each group is separated by the element of space, which locates itself between them. Therefore there is at least as much of space as there is of the matter of the lump. It is owing to the existence of this space that lumps of stone and iron can be broken up, or cut into pieces, or pounded into dust, or melted.