Page:A History of Hindu Chemistry Vol 1.djvu/158

8 distinguishing quality. It is defined as a substance hot to the feel. [Heat, then, and light are identified as one substance.]

"It has the qualities of earth except smell, taste, and gravity. It is eternal, as atoms; not so, as aggregates.

"Organic luminous bodies are beings abiding in the solar realm. The visual ray, which is the organ of sight, is lucid. Unorganic light is reckoned fourfold: earthy, celestial, alvine and mineral. Another distinction concerns sight and feel; as light or heat may be either latent or manifest, in respect of both sight and feel, or differently in regard to either. Thus fire is both seen and felt; the heat of hot water is felt but not seen; moonshine is seen, but not felt; the visual ray is neither seen nor felt. Terrestrious light is that, of which the fuel is earthy, as fire. Celestial is that of which the fuel is watery, as lightning and meteors of various sorts. Alvine is that of which the fuel is both earthy and watery: it is intestinal, which digests food and drink. Mineral is that which is found in pits as gold. For some maintain that gold is solid light; or, at least that