History of Chemistry in Ancient and Medieval India, Incorporating the History of Hindu Chemistry by Acharya Prafulla Chandra Ray c40.s3.30

c40.s3.30

The four kinds of atoms are *earth, ap, tejas,* and *vayu* atoms, possessed of characteristic mass, numerical unit, weight, fluidity (or its opposite), viscosity (or its opposite), velocity (or quantity of impressed motion—*vega*); also characteristic potential colour, taste, smell or touch, not produced by the chemical operation of heat *Akasa* has no atomic structure and is absolutely inert, being posited only as the substratum of sound, which is supposed to travel wave-like in the manifesting medium or vehicle of *vayu* (air). Only the other four *bhutas* unite (or disunite) in atomic or molecular forms. The orthodox view is that the presence of *earth-atoms* is necessary whenever chemical transformation under the operation of heat takesplace.