Robert Boyle and The Sceptical Chymist

The end of an old natural philosophy is rarely declared by those who hate it. More often it is closed, courteously and at a writing desk, by a man who was raised inside its vocabulary and has simply found that the vocabulary will not answer when he asks the furnace a plain question. He does not burn the old books. He sets a dialogue beside them and lets four reasonable voices do the dismantling, so that the reader, watching the argument unfold, comes to the conclusion himself and supposes he was the one who thought of it.

THE SEVENTH SON

He is the Honourable Robert Boyle, born at Lismore Castle in County Waterford on the twenty-fifth of January 1627, seventh son of Richard Boyle, the Great Earl of Cork, who at his death in 1643 was the wealthiest man in Ireland. From that estate Robert had inherited a private income of three thousand pounds a year, which is to say he had inherited the rarest condition in seventeenth-century Europe: a gentleman with no employment to seek and no patron to flatter. He had been schooled at Eton, sent on a Continental tour from 1639 to 1644, settled at Stalbridge in Dorset, and from 1656 had kept a laboratory at Christ Church, Oxford, with a young paid assistant named Robert Hooke at the bench beside him. Since the death of Cromwell he had lodged in London with his sister Lady Ranelagh, on the north side of Pall Mall, in a house whose upper floor he had turned into a furnace room.

Behind him stood two thousand years of European alchemy resting on two supports. From Aristotle, the four elements: earth, water, air, fire. From Paracelsus, the three principles: salt, sulphur, mercury. Every apprentice in every European laboratory had been taught, on his first morning at the furnace, that all matter could be sorted into one or the other of these schemes. Fifteen years of his own careful weighing had told him that neither scheme predicted what the crucible actually gave back. The theories were, in plain reading, wrong. The harder question was what to put in their place that would not be another scheme of the same kind, conjured in the head and imposed on the bench.

THE LABORATORY AT PALL MALL

It is an evening in March 1661. The candles on the bench burn unsteadily where the draught comes off the alembic. Below in the street the link-boys are calling. The room smells of charcoal and of the vinegar he uses to clean glass. On the long oak board lie the folio sheets of the dialogue, near three hundred and eighty quarto pages in his clerk's careful hand, stacked and weighted with a brass weight against the draught. The printer Henry Hall is expecting them within the week. They are ready, and he is not yet ready to send them.

He has set the argument in the old Platonic shape, four speakers in a garden: Carneades the sceptic, who is to carry his own case; Themistius for the Aristotelian; Philoponus for the Paracelsian spagyrist; and Eleutherius, the candid young listener, who stands in for the reader and asks the questions the reader would ask. He had chosen the dialogue form because he did not wish to be seen pronouncing. A man who pronounces is answered by another man pronouncing. A man who lets four voices speak in a garden is answered only by the reader's own assent.

A SECOND OF TIME IN A LABORATORY

Now, at the bench, he reads back the page on which Carneades makes the substitution. The old schemes are taken apart by experiment, that is plain. The harder line is the one that says what an element is. He has written that an element is to be understood as that which, by the operations now in our hands, cannot be reduced to anything simpler. He weighs the sentence as he weighs a sample, and feels how much of his life he is putting onto the pan. The clause now in our hands is the whole of the wager. It hands the definition over to the bench, and to every bench that will come after this one. It says that the list of elements is not closed by Aristotle nor by Paracelsus nor by himself, but only by what tomorrow's furnace cannot further break. He counts on his fingers what the present bench can name: gold, silver, copper, tin, lead, mercury, iron, sulphur, carbon, antimony, arsenic, bismuth, zinc. Perhaps a score in all. There will be more. He cannot say which, only that the form of the definition tells the laboratories of the next century where to look and how to know when they have found one. A scheme imposed from above closes the world. A definition that defers to the bench opens it.

He could soften the clause. He could keep the four elements as a courtesy to the schools and slip the new thought in below them. He has friends at Oxford and at the Hartlib circle who would prefer it so. The thought rustles among the folio sheets and is set aside. The requisites of a good hypothesis, he had written in another paper, are that it be intelligible, that it contain nothing impossible, and that it be sufficient to explain the phenomena. The old schemes are not sufficient. He will not pretend otherwise to spare them. The candle gutters. He signs the last sheet and weights it down.

THE SCEPTICAL CHYMIST

The folio went to Henry Hall in late March. The Sceptical Chymist: or Chymico-Physical Doubts and Paradoxes was published in London by F. Crooke in November 1661, an octavo of some three hundred and eighty pages in a first impression of about a thousand copies. It moved through the coffee-houses and the college rooms in the slow way such books move, without scandal and without fanfare, and was read by the men who needed to read it. In July 1662 the Royal Society received its charter; Boyle was a founding fellow and sat on its Council for the next twenty-eight years. The same year, in the second edition of New Experiments Physico-Mechanical, Touching the Spring of the Air, he gave the inverse relation of pressure and volume in a confined gas at constant temperature, which the schools of every country now teach to children as Boyle's Law.

THE OLD ART IN ITS GARDEN

Somewhere in the same season an older spagyrist, of the sort the dialogue had named Philoponus, opened the book at his own bench in a cellar off Lothbury and read what Carneades had to say about salt, sulphur and mercury. He had ground those three principles into his apprentices for forty years. He read the passage twice. He did not throw the book on the fire, because the courtesy of the dialogue gave him no occasion to. The young man at his elbow, who had been about to draw off a distillate, set down the receiver and asked, quite mildly, what the master now wished him to call the residue in the retort. The master had no name ready. The art he had been taught was not refuted in that moment. It was simply, in the polite manner of the book, no longer the only thing one could say about a residue. He returned to his furnace. The apprentice, in time, would buy his own copy.

THE LONG AFTERMATH

Boyle lived another thirty years at his sister's house in Pall Mall and published some forty further works. He endowed by his will the Boyle Lectures on natural philosophy and religion, first delivered in 1692 at St Mary-le-Bow and continued there to this day. He paid for John Eliot's Algonquin Bible, printed at Cambridge in Massachusetts in 1663, the first Bible printed in North America. He died at Pall Mall on the thirty-first of December 1691, sixty-four years old, a week after Lady Ranelagh, and was buried in the chancel of St Martin-in-the-Fields. The old church was pulled down and rebuilt between 1722 and 1726, and the grave lies now beneath the present floor.

The schemes that the dialogue had unseated took another century to fall away entirely. Lavoisier in Paris, weighing his oxygen against Boyle's clause, would close one half of the work; Mendeleev at Saint Petersburg, ranging the elements by weight into the periodic table, would close the other. The list, twenty substances in 1661, stands now at one hundred and eighteen. Each one was admitted to it by the test Boyle had written in candlelight at Pall Mall: that it could not, by the operations then in our hands, be reduced to anything simpler. The clause is doing its work still, in every laboratory on earth, every time a new substance is brought to the bench and asked what it is.

THE WEIGHT ON THE FOLIO

A great moment in the history of an art is not always loud. Sometimes it is only a man at a candlelit bench in a borrowed upstairs room, choosing not to soften a clause out of courtesy to his teachers, and weighting the page down against the draught so that the printer's boy will find it in the morning where he left it. The brass weight on the folio sheet at Pall Mall, in March 1661, is the small instrument by which a borrowed laboratory in his sister's house became the first room of modern chemistry.