History of Chemistry in Ancient and Medieval India, Incorporating the History of Hindu Chemistry by Acharya Prafulla Chandra Ray c40.s3.25

c40.s3.25

Mere juxtaposition is insufficient; linking of atoms or molecules must follow before a compound can be produced. The linking takes place under different conditions. Ordinarily speaking, one particle of matter must be negative, and the other positive; the two particles must have two peculiar opposite qualities, roughness and smoothness (dryness and viscosity ?), to make the linking possible. But no linking takes place, where the qualities, though opposed, are very defective or feeble. We have seen that, ordinarily speaking, two homogeneous particles, i.e., both positive, or both negative, do not unite. This is the case where the qualities are equal in intensity. But if the strength or intensity of the one is twice as great as that of the other, or exceeds that proportion, then even similar particles may be attracted to each other. In every case, change of state in both the particles is supposed to be the result of this linking, and the physical characters of the aggregate depend on the nature of this linking. When particles of equal intensity (negative and positive) modify each other, there is mutual action; in cases of unequal intensity the higher intensity transforms the lower, it being apparently thought that an influence proceeds from the higher to the lower. All changes in the qualities of atoms depend on this linking. This appears to be a crude anticipation of the ionic theory of chemical combinations, very crude but immensely suggestive, and possibly based on the observed electrification of smooth and rough surfaces as the result of rubbing. The Tattvarthadhigama of Umasvati, which expounds the theory, most probably dates back to the first half of the first century A.D.