CHEMICAL FORCE.

BY EDWARD DAVIES, F.C.S.

THE Contemplation of the forces of nature seems to have been one of the earliest exercises of the human mind. Admiration of force leading to its eventual deification is natural to the savage, with whom the rule of the strongest is a universal law. To worship the sources of power greater than that possessed by mortals-the sun whose genial heat gave life to nature, the winds which could sweep away the frail dwellings which protected him, or tear up the forest trees, the waves whose resistless force threatened to swallow up the solid earth was to be expected from those whose chief was the strongest man of the tribe. Even when intellectual power began to assert its predominance over brute force, it did so at first solely because it was more powerful, cunning was more than a match for strength, and the worship of wisdom was only another form of the worship of force.

When man at first began to investigate the mystery of nature, no doubt the facts lying on the surface engrossed his attention. Ore was smelted, and the metal obtained applied to man's use many a time before speculation sought to explain its production. As time rolled on men endeavoured to find out the causes of the phenomena which they witnessed, and gravitation, electricity, magnetism, heat, light, and the action of living beings were scrutinised to explain the mighty works we see in the heavens and the earth. Chemical force was one of the last to reveal itself as a mighty factor in the world of nature. Until chemistry brought to light the complex constitution of material objects, there was no basis for theory as to the way in which that complexity arose, and in

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the days of alchemy supernatural agencies were fondly imagined as superintending the formation of minerals in the earth, and even aiding the operations in the laboratory. Thus, Basil Valentine says, "That the first beginning to beget metalline seeds is wrought in the earth by a sidereal impression; which quality presseth from above into the æther in the earth, and worketh continually a heat there with the help of the elements, for both must be together: the earthy affords an imagination that the earth is fitted for conception, and is impregnated, the elements nourish and feed this fruit, and bring it on by a continued hot quality into perfection; the earthy substance affords a form thereunto, thus at the beginning the metalline and mineral seed is effected, namely, by an astral imagination, elemental operation, and terrestrial form; the astral is heavenly, the elementary is spiritual, and the earthy is corporeal; these three make of their first centre the first essence of the metalline seed."

A more poetical form of the same idea is that spiritual beings, gnomes and sylphs, inhabited the interior recesses of the earth and watched over the growth of minerals, and sometimes they aided the miner, but more frequently they were his enemy. A relic of this past fancy survives in the name of the metal cobalt, derived from Kobold, a mine demon who used this metal to deceive the unlucky miner.

The idea of supernatural force in connection with chemical operations was connected with the theory of the transmutation of metals. The possibility of a total change of properties, with a substance remaining unchanged, was more miraculous to the alchemist than it is to ourselves with the phenomena of allotropism before us. Yet they believed that it might be brought about, though scarcely by purely human means; so, according to the religious temperament of the man, he asked the aid of the Deity, as in Basil Valentine's oft

repeated invocations of the Trinity, or sought demoniacal help, and would have sold his soul to the Devil for the Philosopher's Stone, if such a bargain could be made.

Older views were more philosophical than these. In a treatise on Philosophy, called the Vaiseshika, by Kanada, an Indian sage, who probably lived some centuries before the Christian era, substance is divided into nine divisions1, earth; 2, water; 3, light; 4, air; 5, ether; 6, time; 7, space; 8, soul; and 9, mind. Of these the first four and the ninth are affirmed to be formed of. atoms. These atoms are round, extremely minute, invisible, incapable of division, eternal in themselves, but not in their aggregate forms. They have individually a specific difference. Light, for example, is formed by the aggregation of luminous atoms. Other substances are formed in a similar manner. These atoms combine by twos in an aggregate, or by threes. They also combine by fours, &c. They are innumerable in extent, and are perpetually united, disintegrated, and reintegrated by an unseen peculiar virtue or force-adrishta. What idea Kanada intended to convey by this term, adrishta, the unseen, it is not possible to say. He may mean a force, or "potentiality," inherent in the atoms themselves.*

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The terms earth, water, and air are probably used, as they were by other early philosophers, to indicate the solid, liquid, and gaseous form of matter. That all solid matters, although supposed to consist of earth, were not identical, was evident to any one, so the difficulty was met by a supposition that qualities" might be attached to the "earth," and thus bodies endowed with varied properties be derived from the original elementary bodies. "Kanada recognised seventeen qualities-colour, savour, odour, tangibility, number, extension, individuality, conjunction, disjunction, priority, posteriority, intellections, pleasure, pain, desire, aversion, and * Hindu Philosophy, by John Davies, M.A. Trubner's Oriental Series.

volition. To these his followers added the seven following:gravity, fluidity, viscidity, self-reproduction (including motion, elasticity, and memory), sound, with merit and demerit." Many of these refer to the soul, which he considered as a substance, but most of the physical properties of bodies are included in the list.

The description of atoms and their combinations might have been taken from a modern chemical treatise. If he meant that the force which causes them to combine is inherent in the atoms, he held a view almost the same as that taught by the earlier chemists under the name of affinity. This view is now attempted to be set aside in favour of the theory that forces not necessarily inherent in the atoms bring about their combinations, and that these forces are electricity and heat. These views are those which I propose to examine, and to the former and older one I am disposed to give the preference.

It may be useful to those who have not studied the science of Chemistry, and to those whose knowledge of it was acquired a long time since, if I give an outline of the theory of the constitution of matter as held by chemists of the present day, or, at least, by the majority of them who accept Dalton's Atomic Theory.

All matter is supposed to consist of atoms, defined as exceedingly minute portions of matter, indivisible by any known chemical or mechanical means, and the smallest quantity of an element which can enter into the composition of a compound. These atoms are of very different weights, varying from a relative weight of 1 for Hydrogen to 240 for Uranium, but all the atoms of the same element are of the same size and weight. In the majority of cases atoms of different elements appear to occupy equal portions of space, either being of the same size, or having more or less intervening space between them, so that the atom and the inter