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History of Chemistry in Ancient and Medieval India, Incorporating the History of Hindu Chemistry by Acharya Prafulla Chandra Ray c40.s5: Chemical Action And Heat

History of Chemistry in Ancient and Medieval India, Incorporating the History of Hindu Chemistry by Acharya Prafulla Chandra Ray c40.s5

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English

Chemical Action And Heat

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The operation of heat is, of course, universally implied in chemical combinations. Where the application of external heat is wanting, Vatsyayana, the great Doctor of the Nyaya, points to the operation of internal heat. In the case of combustion, we have seen, Vijnana-bhikshu explains the heat as latent in the Earth-substance, the fuel, from which it breaks forth. Udayana points out that the solar heat is the source of all the stores of heat required for chemical change in the world. The change of colours in grasses, for example, is due to *tejas*, in the form of latent (invisible) heat, not in the form of *agni* (fire); and the cold in winter cannot take away this store derived from the sun (Udayana,—Kiranavali). Similarly, it is under this solar heat that the unripe mango ripens, *i.e.*, changes colour, taste, smell, etc., showing that there is chemical transformation, or subtile decomposition and recomposition, going on; and this is also the case with the rusting of the metals, which is a combustion due to the solar heat, even as the conversion of food into chyle and of chyle into blood are instances of chemical action due to the internal animal heat. But the kind of contact with heat-corpuscles, in other words, the kind of chemical action which transforms colours, is supposed to differ from that which transforms flavour, and this last from that which produces a change of smell, or tactile quality (Nyayabodhini on Annam Bhatta's Tarkasamgraha). Heat and light rays are supposed to consist of indefinitely small particles, which dart forth or radiate in all directions rectilinearly with a sort of conical dispersion and with inconceivable velocity. They may either (1) penetrate through inter-atomic (or *inter-molecular*) spaces as in cases of conduction of heat, which when applied under the pot boils the water, or fries the paddy where there is no chemical action in the pot, no decomposition and recomposition of its atoms, no change in the molecular collocation; or, as with light rays in cases of translucency or transparency penetrate through the inter-atomic spaces with *parispanda* of the nature of deflection or refraction in the same way as when fluids penetrate through porous bodies; or, (2) these rays or particles may impinge on the atoms and rebound back—which explains reflection, or otherwise be obstructed by the atoms in their path, which would explain degrees of opacity, the casting of shadows, etc., all these operations being also physical, and unattended with decomposition and recomposition or alteration of molecular grouping; or lastly, (3) these rays may strike the atoms in a peculiar way, so as to break up their grouping, may transform the physicochemical characters of the atoms, and may again recombine them, all by means of continual impact with inconceivable velocity, an operation which explains all cases of chemical combination.

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ARRANGEMENT OF ATOMS IN SPACE

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The Nyaya conceives atomic magnitudes as *parimandalya*, a term indicating a spherical shape. To conceive position in Space, Vachaspati takes three axes, one proceeding from the point of sunrise in the horizon to that of sunset on any particular day (roughly speaking from the East to the West); a second bisecting this line at right angles on the horizontal plane (roughly speaking from the North to the South); and the third proceeding from the point of their section up to the meridian position of the sun on that day (roughly speaking, up and down). The position of any point in Space, relatively to another point, may now be given by measuring distances along these three directions, *i.e.*, by arranging in a numerical series the intervening points of contact, the less magnitude or distance being that which comes earlier in this series, and the greater that which comes later. The position of any single atom in space with reference to another may be indicated in this way with reference to the three axes. But this gives only a geometrical analysis of the conception of three-dimensioned Space, though it must be admitted in all fairness that by dint of clear thinking it anticipates in a rudimentary manner not only the foundation of solid (co-ordinate) geometry, but also of the geometry of position, and especially the conception of Space as a manifold, which alone can serve as the basis of a generalisation comprehending all different kinds of geometry, Euclidean and non-Euclidean.

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The original physical arrangement of atoms is also given. Each atom is in contact with six other atoms, which gives a cubical arrangement. (Vachaspati, Tatparyyatika, Chap. IV.

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Ahnika 2, Sutra 25). This is the typical primordial arrangement; and variations in the collocation of atoms and molecules, as we have seen, were conceived to account for the variety of isomeric modes of the same *bhuta*, as well as of *mono-bhautic* and *poly-bhautic* compounds.

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The molecular arrangement in the case of the *bi-bhautic* compounds is very peculiar. Two substances, say Earth and *ap* (water), form a quasi-compound first: and each substance breaks up into atoms, when one atom of Earth comes into contact with one of *ap*. But the two do not form a binary molecule. Instead, this contact of heterogeneous atoms leads to a curious result. The atom of Earth combines with a neighbouring atom of its own class, and forms a binary molecule. Simultaneously the atom of *ap* combines with another *ap*-atom, and forms a binary molecule. Now the first binary molecule links on to the atom of *ap*, and similarly the second binary molecule links on to the atom of Earth. The moment after, the two binary molecules take on the physicochemical character of Earth and *ap* respectively, and simultaneously with the assumption of these physicochemical characters, the binary molecules enter into complex contact. In all this process, work is done only in the first instant, in the contact of an atom of Earth with one of *ap*; the resulting contacts, of atom with binary molecule and of the binary molecules with each other, involve no further expenditure of Energy. Thus we get a particle holding two binary molecules (of Earth and *ap* respectively) in complex contact, and such particles continue to be formed. In this way the particles of the two substances arrange themselves, and the peculiarity of this molecular arrangement explains the resulting mixed or compound qualities of this class of quasi-compounds.

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The whole process may be graphically represented as follows :—

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[Figure: Molecules of a bi-bhautic quasi-compound,—graphic formula of complex contact E = an atom of Earth, W = an atom of Water (*ap*) E / | / E = a binary molecule of Earth, W / | / W = a binary molecule of Water (*ap*)]

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Molecular and Atomic Motion—Parispanda.

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*Parispanda* sometimes stands for atomic and molecular motion, but more often for the subtile motion of atoms or molecules. The radical meaning of the term is whirling or rotary motion, a circling motion, but it may also include simple harmonic motion (e.g., vibration). All action, operation or work, is ultimately traced to this form of subtile motion lodged in the atoms or in the matter-stuff. The Vedanta, for example, speaks of a cosmic vibratory motion. *Akasa* in the Vedanta, as we have seen, is the first stadium in the evolution of matter, which gives off *vayu*, which gives off *tejas*, and so on; but *akasa* (Ether) itself passes through two stages before the emanation of the *sukshma-bhuta vayu*—(1) the motionless ubiquitous primordial matter-stuff (*bhutadi* in Samkhya) called *puranam kham*, and (2) a subtile integration, the pure unquintuplicated *sukshma-bhuta* called *vayuram kham* (tanmatra stage in Samkhya). It is this subtile *akasa*, in its tanmatric integration, i.e., in the derivative form, which is subject to an incessant *parispanda*. The gaseous stage of matter (the Vedantic *vayu*) is indeed matter in a state of *parispandic* motion. The Samkhya also conceives this *parispanda* to characterise every process and phenomenon of cosmic evolution *Bhutas*, organisms, mental organs, as modes of *Prakriti*, are all subject to this *parispanda* On the other hand, *Prakriti* as the *avyakta*, the a-cosmic, the unmanifest ground, with resolution only of like to like, is devoid of all *parispandic* motion. The Nyaya-Vaiseshika finds *parispanda* in all forms of matter, except *akasa* which, in that system, is non-atomic and incapable of any change or activity. But all atoms, from those of *vayu* downwards, are in incessant motion. The world at bottom is an infinitude of continually whirling (or vibratory) particles. All physical action consists in motion. The Nyaya-Vaiseshika rejects force, power, operation, except as modes of motion. But, though all action of matter on matter is thus resolved into motion, conscious activity is sharply distinguished from all forms of motion In this Nyaya-Vaiseshika differs from Samkhya-Vedanta, which, as we have seen, considered everything other than Intelligence, the *Purusha* or the transcendental Self, to arise in the course of cosmic Evolution, and therefore, to be subject to *parispandic* motion.

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The wave-motion and current-motion or convection have been termed *gati-santana* (*gati* means velocity, *santana* denotes serial motion; motion which progresses forwards). Mere vibration has been described as *kampa-santana* or *spandana*. Charaka notes three kinds of *santanas*, serial motions, viz., those of water, sound and light. Chakrapani points out that a wave of sound travels more rapidly than a wave of water, and much less rapidly than a ray of light. The last named implies the rectilinear propagation of indefinitely minute corpuscles, in all directions, with inconceivable velocity, and a sort of conical dispersion (*cf.* Uddyotakara—Vachaspati). A wave of water implies the transmission of vibratory motion in the water particles A wave of sound is conceived by some on the analogy of a wave of water; only the air waves, or the sound waves in and through the vehicle of air waves, travel by concentric circles, not in one but in all planes (this assumes transverse waves). Others hold that the air waves, or the sound and air waves, are propagated by the transmission of the vibration in all directions, leading to conjunction and disjunction of air particles, so that the waves may be said to expand by alternate concentric spherical layers of rarefaction and condensation (this assumes longitudinal waves). The Vakya-padiya describes articulate sounds (*varnas*), and indeed all sounds (*sabdas*), as only forms of air set in motion, with rarefaction and condensation, and capable of variations of velocity and configuration (Vakya-padiya, Kanda I, Sloka 109).

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The Weight of Air

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Udayana argues that air must be a distinct and independent *bhuta*; for if air were made of the *earth-bhuta*, it would have weight, and it has none. To prove the absence of weight, he refers to an experiment.

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A small bladder made of thin membrane, filled with air, will not cause a greater descent in the scale of a balance than the same bladder weighed empty. Hence, the air possesses no weight. Then Udayana makes an interesting statement. It may be objected, he says, by one who accepts the weight of air—that this argument is inconclusive. For, a counter-experiment may be suggested. The balloon filled with smoke (or gas—*dhum*) rises in the air, whereas the air-filled balloon comes down. This would go to show that air has weight. Udayana replies that this would only show that both smoke and air have no weight. The Hindus appear to have been ignorant of the principle of Archimedes, at least as applied to gases. Vallabhacharya in the Lilavati speaks of a peculiar resistance to sinking exercised by water, which explains the tendency in certain objects to float or to come up to the surface of the water: but the description shows that he had no clear ideas on the subject (*cf*. Udayana, Kiranavali—*vayu-nirupanam*).

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For a fuller reference to the subjects dealt with in this section see "Positive Sciences of the Ancient Hindus" by the same author.

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| ASIA | AEGEAN, GREECE, AND WESTERN EUROPE |
| | → |
| Kish, Ur tin-bronze | |
| imitation te a che- s writings ry direc- apparatus l symbo- netal and Prepared | EARLY MINOAN. *Knossos* : Copper, gold, silver, bronze, lead Purple dye, glaze *Mycena* Glass. THE HITTITES Useful iron (c 1400 B.C), steel weapons Tin oxide glaze, cobalt glass IRON AGE (c 1200 B.C.) CLASSICAL GREECE Thales (c.624-545 B C.)—Water, primal matter. Anaximander (c 611-546 B.C.) — 'Apeiron', primal matter. Anaximenes (c. 550 B C ) — Air, primal matter. Heraclitus (c. 536-470 B.C.) --Fire, primal matter. Pythagoras (c. 570-490 B.C.) -Geometrical conception of matter. Empedocles (c. 490-430 B.C.) —Four element theory. Anaxagoras (c. 500-427 B.C.) postulated an external intelligence. Leucippus (c. 500 B.C.), and Democritus (c. 460-370 B.C ) proposed an atomic theory. All matter consists of eternal, moving, indestructible atoms, qualitatively alike but differing in size, shape and mass. Aristotle (384-322 B.C) postulated the primary matter, called '*hule*' Theophrastos (315 B.C.) described the manufacture of white lead. WESTERN EUROPE |

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