Element

The idea of element answers one of the oldest questions put to nature: of what are things made, and into what do they return when they perish? It covers the four elements of earth, water, air and fire, the fifth essence some placed above them, the hot, cold, moist and dry that were thought to compose them, the atoms that rival schools set in their place, and finally the substances that modern chemistry isolates by experiment. In the Harvard Classics the idea runs from the Phaedo, where the body is said to be held together by hot and cold, wet and dry¹, to Faraday’s lecture table, where an electric current parts water into two gases². It is a great idea for these books because it lies where physics, theology and morals meet. Dante uses the elements to mark the boundary between what God makes directly and what he makes through secondary causes. Marcus Aurelius uses them to make peace with death. Faraday uses them to show his audience what chemical knowledge consists in.

The fourfold scheme is the common inheritance of the older authors. Dante’s Paradise holds that air, fire, earth, water and the things compounded of them are created and corruptible, whereas the angels and the heavens are created directly and endure³. Milton, describing creation, has Earth, Flood, Air and Fire, together with the quintessence, hasten to their appointed quarters⁴. Spenser turns the same doctrine into compliment: since his beloved is plainly made of none of the four, she must be made of the fifth element, the sky⁵. Sir Thomas Browne treats the earth as a composition of fire, water, earth and air, and he adds that fire’s last action is to vitrify, not to annihilate⁶. Thomas à Kempis, counselling the contemplative to stay at home, observes that heaven, earth and the elements, of which all things are made, are enough to behold there⁷. Even Descartes, setting out a new physics, still gives fire a privileged place as the only source of light besides the stars, and asks how composite bodies are generated⁸. For Marcus Aurelius the elements supply a moral contrast: their movements are all around us, but the motion of virtue is not among them⁹.

Behind the four elements stand the qualities. In the Phaedo the view is put forward that the soul is a proportionate mixture of the hot and cold, wet and dry that hold the body together¹. The idea of element is thus stretched to cover the soul as well as the body. Bacon gives the qualities a new office. Dense and rare, hot and cold, and the other cardinal virtues of nature are its primary elements, as letters are the elements of speech, and from them everything else is spelled¹⁰. The alphabet image looks forward to analysis, but it is still an analysis into qualities, not into substances. The poets keep the older picture of qualities at war. In Milton’s Chaos, Hot, Cold, Moist and Dry, attended by embryon atoms, fight for mastery in what is at once the womb and the grave of Nature¹¹. Dryden has the same jarring atoms, cold, hot, moist and dry, fall into order at the voice of harmony¹². The analytic habit outlives the qualities themselves. When Kelvin resolves the complicated motion of the tides into simple harmonic constituents¹³, he applies to motion the same procedure of finding the simple parts out of which a whole is composed.

Other traditions count the constituents differently. The Bhagavad-Gita names earth, water, flame, air and ether, and adds life, mind and individuality, as eight manifest aspects of the Lord¹⁴. Here the elements are not stuff set over against spirit but modes of the divine. The Buddhist writings speak of the elements of being as originating from dependent factors acting together¹⁵, so that the elements are themselves conditioned, not first. In the alchemical tradition reported by Harrison, quicksilver and sulphur are the father and mother of all metals¹⁶. Goethe’s Faust carries the old doctrine into the world of spirits. He pronounces the Spell of Four over salamander, nymph, sylph and kobold¹⁷, and he holds that whoever would master spirits must know the use and might of the primal Four¹⁸. Emerson, writing in the age of chemistry, looks back on alchemy with some sympathy. Chemistry takes things to pieces but does not build them, he says, and the alchemists who sought to transmute elements were moving in the right direction¹⁹.

The deepest controversy in these books concerns not how many elements there are but whether their combinations are governed. Marcus Aurelius returns to the question again and again in the form of a dilemma. Either there is providence or there is a fortuitous concurrence of atoms²⁰. Either all things proceed from one intelligent source, or there are only atoms in mixture and dispersion²¹. The universe is either a concourse of atoms or a system governed by nature²². One horn of the dilemma is that indivisible elements are the origin of all things²³. The other is that, if things are not mere atoms, nature orders them²⁴. He applies the dilemma to the dead as well: they have either been received back among the seminal principles of the universe or been scattered among the atoms²⁵. George Long’s commentary makes the contrast explicit. Matter consists of elemental parts into which things dissolve, and Antoninus sets the Stoic seminal principles against the atoms of Epicurus²⁶. Marcus usually leaves the dilemma standing and draws the same moral from either horn. The moderns try to settle it. Bacon argues that it is less credible that unplaced atomic seeds should produce order without a God than that ordered elements should need none, so that atomism, of all philosophies, most requires a divine cause²⁷. Rousseau’s vicar presses the atomist on motion, asking whether each atom has a motion of its own, and finds that either answer leads to absurdity²⁸. Ancients and moderns agree that the bare elements cannot account for order. They differ in that the Stoic can live with uncertainty, while Bacon and Rousseau treat the question as decidable in favour of mind.

Within the Stoic picture the elements are never at rest. Marcus holds that the changes of the elements preserve the universe²⁹, and that living beings are compounded of elements that continually change into one another³⁰. He quotes Heraclitus: the death of earth is to become water, the death of water to become air, the death of air to become fire, and the cycle runs back again³¹. Bodies pass into blood and into the aerial or fiery elements³², and he urges the reader to dwell on these transformations³³. Each element also tends toward its own kind, earth to earth and fire to fire³⁴. Yet the air, fire, earth and water in us submit to the universal order even against their natural tendencies, and only the intelligent part of us disobeys³⁵. The elements here become a rebuke to reason. Milton’s cosmos has the same circulation in a Christian setting. At creation like is gathered to like, and air, water and earth are separated out of the primal fluid mass³⁶. Afterwards the four elements mix in a perpetual circle and nourish all things³⁷. The grosser feed the purer, earth the sea, the sea the air, the air the fires, and moon and sun are nourished by exhalations³⁸. Milton’s cycle is hierarchical, rising toward the heavens, where the Heraclitean round runs both ways without a summit.

The same doctrine of return governs the Stoic meditation on death. Epictetus teaches that when we die the body’s parts go back to their elements, to fire, earth, spirit and water³⁹. Marcus likewise traces our earthy, watery and fiery parts to their sources, and insists that nothing comes out of nothing and nothing returns to nothing⁴⁰. Breath is given back to the element from which it was drawn⁴¹. The dead are dissolved into their proper parts, which are elements of the universe⁴², the solid going to the earthy and the airy to the aerial⁴³. Even on the atomist hypothesis the conclusion is no harsher, for death is then a dissolution of atoms or a dispersion of elements that feel nothing⁴⁴. Browne’s remark that fire ends in glass, not in nothing⁶, belongs to the same conviction that the stuff of things persists through every change of form.

With Faraday the idea of element becomes experimental and acquires a definition. Elements are those things from which nothing else can be got. A candle is not an element, since much can be extracted from it, while hydrogen is, and its name records that it generates water⁴⁵. Elements differ by measurable marks, as platinum and aluminium differ in weight⁴⁶. Voltaire’s report of Newton uses the word in a related sense, calling the coloured rays elementary and unchanging, like gold that has been purified⁴⁷. What marks an element in this sense is that it holds out against further analysis.

Water, an element for the ancients, becomes Faraday’s chief example of a compound. He proposes to probe its constituents whatever its state, as ice, water or steam⁴⁸. He decomposes it into gas and recombines it⁴⁹. An electric current separates its parts at different plates, one of which burns while the other supports burning². Water consists of two substances, hydrogen and oxygen, chemically combined⁵⁰, in proportions fixed by volume and by weight, one part to eight⁵¹. Hydrogen is prepared and shown to be combustible, as oxygen is not⁵². The two always combine to form water, as the dew deposited over a candle flame shows⁵³, and they combine only in exact proportions⁵⁴. In the candle lectures the argument converges from several sides. A distinct gas is separated from water⁵⁵, and the hydrogen got from water by iron, potassium or zinc proves to be the same substance found in the candle⁵⁶. Hydrogen yields only water when it burns, and this is a further proof of water’s composition⁵⁷. The battery splits water and collects its parts⁵⁸. The second gas is identified as oxygen because it supports combustion⁵⁹, and water is found to be two volumes of hydrogen to one of oxygen, with the weights stated⁶⁰. In combination oxygen neutralizes the qualities of hydrogen⁶¹, and potassium decomposes water by seizing its oxygen and freeing its hydrogen⁶². Faraday leaves room for further discovery, allowing that water contains bodies besides hydrogen not yet known and still to be separated⁶³.

Air and fire fare as water did. The oxygen from the candle’s water is the same substance found in air⁶⁴, and the atmosphere proves to be oxygen together with another constituent⁶⁵. That constituent is nitrogen, inert, tempering oxygen’s power of combustion⁶⁶. Faraday calls it an inactive element and gives the composition of the air by bulk and by weight⁶⁷. Since nitrogen does not support combustion, another gas must also be present⁶⁸. Carbonic acid is traced back to carbon and oxygen, as water was traced to its elements⁶⁹. All the carbon burned in oxygen becomes carbonic acid, and unburned carbon is what makes the flame bright⁷⁰. The proportions are fixed, six of carbon to sixteen of oxygen making twenty-two of carbonic acid⁷¹. Potassium burning in carbonic acid takes its oxygen⁷², and the carbon thus recovered completes the proof, while wood, candle and coal gas all yield carbon too⁷³. Sugar is shown to be carbon, hydrogen and oxygen, like the candle⁷⁴, and tallow is split into stearic acid and glycerin⁷⁵. Fire is no longer a substance in this account. It is the visible work of elements combining.

Helmholtz adds an account of what that combining is worth. Chemical affinity draws zinc or iron to the oxygen of the air, as Faraday’s combustions show⁷⁶. Carbon and oxygen atoms unite by attraction into carbonic acid, which keeps both elements but has lost its capacity for work⁷⁷. Hydrogen burns with oxygen to water, and the two must be separated again before that capacity is restored⁷⁸. Once separated, they regain their heat-producing affinity⁷⁹. In a battery, zinc oxidizes and water is decomposed, chemical forces overcoming chemical forces⁸⁰. The constituents of exploded powder pass into compounds not easily restored to their first condition⁸¹. The Stoic thought that nothing is lost reappears here in quantitative form, though the modern version adds that the power of the elements to do work can be spent. Newcomb extends the elements to the whole cosmos: stars, sun and earth share the same chemical elements, and this enforces the unity of the universe⁸². Dante had placed the elements below an incorruptible heaven³; Newcomb finds them in the heavens as well.

Between the ancients and the moderns, then, almost everything about the elements has changed. Water and air have become compounds, fire has become a process, and the qualities have given way to weights and volumes. Some convictions have persisted. Bodies are composed of simpler parts, the parts survive the dissolution of the whole, and in Faraday’s fixed proportions, as in the Heraclitean exchanges, the changes keep to a measure. Several questions remain open. Faraday concedes that analysis may go further⁶³, and Emerson doubts that taking things apart explains how they are built¹⁹. The chemists, for their part, do not take up the dilemma Marcus kept posing, whether the union and separation of elements is the work of an ordering intelligence or of atoms meeting by chance^21,27.