Jan 252018

Today is the birthday (1627) of Robert William Boyle FRS, an Anglo-Irish natural philosopher, chemist, physicist, and inventor. Boyle is regarded today as one of the founders of modern chemistry, and one of the pioneers of modern experimental scientific method, even though, like his contemporary, Isaac Newton, he was an alchemist also. He is best known for Boyle’s law, which describes the inversely proportional relationship between the absolute pressure and the volume of a gas, if the temperature is kept constant within a closed system. Among his publications, The Sceptical Chymist is seen as a cornerstone book in the field of chemistry. He was a devout and pious Anglican and is noted for his writings in theology.

Boyle was born at Lismore Castle, in County Waterford, Ireland, the seventh son and fourteenth child of the 1st Earl of Cork (‘the Great Earl of Cork’) and Catherine Fenton. Lord Cork, then known simply as Richard Boyle, had arrived in Dublin from England in 1588 during the Tudor plantations of Ireland and obtained an appointment as a deputy escheator. He had amassed enormous wealth and landholdings by the time Robert was born, and had been created Earl of Cork in October 1620. Catherine Fenton, Countess of Cork, was the daughter of Sir Geoffrey Fenton, the former Secretary of State for Ireland, who was born in Dublin in 1539, and Alice Weston, the daughter of Robert Weston, who was born in Lismore in 1541.

As a child, Boyle was fostered out to a local family, as were his elder brothers. Boyle received private tutoring in Latin, Greek, and French and when he was 8 years old, following the death of his mother, he was sent to Eton College in England. His father’s friend, Sir Henry Wotton, was then the provost of the college. During this time, his father hired a private tutor, Robert Carew, who had knowledge of Irish, to act as private tutor to his sons in Eton. Boyle’s first language was Irish. After spending over three years at Eton, Boyle travelled abroad with a French tutor. They visited Italy in 1641 and remained in Florence during the winter of that year studying the “paradoxes of the great star-gazer,” Galileo Galilei, who was elderly but still living in 1641.

Boyle returned to England from continental Europe in mid-1644 with a keen interest in scientific research. His father had died the previous year and had left him the manor of Stalbridge in Dorset as well as substantial estates in County Limerick in Ireland. Boyle then made his residence at Stalbridge House, from 1644 to 1652, and conducted many experiments there. From that time, Boyle devoted his life to scientific research and soon took a prominent place in the band of enquirers, known as the “Invisible College”, who devoted themselves to the cultivation of the “new philosophy”. They met frequently in London, often at Gresham College, and some of the members also had meetings at Oxford.

Having made several visits to his Irish estates beginning in 1647, Boyle moved to Ireland in 1652 but became frustrated at his inability to make progress in his chemical work. In one letter, he described Ireland as “a barbarous country where chemical spirits were so misunderstood and chemical instruments so unprocurable that it was hard to have any Hermetic thoughts in it.” In 1654, Boyle left Ireland for Oxford to pursue his work more successfully. An inscription can be found on the wall of University College in the High Street in Oxford (now the location of the Shelley Memorial), marking the spot where Cross Hall stood until the early 19th century. It was here that Boyle rented rooms from the wealthy apothecary who owned the Hall.

Reading in 1657 of Otto von Guericke’s air pump, he set himself with the assistance of Robert Hooke to devise improvements in its construction, and with the result, the “machina Boyleana” or “Pneumatical Engine”, finished in 1659, he began a series of experiments on the properties of air. An account of Boyle’s work with the air pump was published in 1660 under the title New Experiments Physico-Mechanical, Touching the Spring of the Air, and its Effects. Among the critics of the views put forward in this book was a Jesuit, Francis Line (1595–1675), and it was while answering his objections that Boyle made his first mention of the law that the volume of a gas varies inversely to the pressure of the gas, which among English-speaking people is usually called Boyle’s Law after his name. The person who originally formulated the hypothesis was Henry Power in 1661. Boyle in 1662 included a reference to a paper written by Power, but mistakenly attributed it to Richard Towneley. In continental Europe the hypothesis is sometimes attributed to Edme Mariotte, although he did not publish it until 1676 and was likely aware of Boyle’s work at the time.

In 1663 the Invisible College became The Royal Society of London for Improving Natural Knowledge, and the charter of incorporation granted by Charles II of England named Boyle a member of the council. In 1680 he was elected president of the society, but declined the honor because of a scruple about oaths. In 1668 he left Oxford for London where he lived at the house of his elder sister Katherine Jones, Lady Ranelagh, in Pall Mall. His contemporaries widely acknowledged Katherine’s influence on his work, but later historiographies dropped her from the record. Theirs was “a lifelong intellectual partnership, where brother and sister shared medical remedies, promoted each other’s scientific ideas, and edited each other’s manuscripts.”

In 1669, Boyle’s health, never very strong, began to fail seriously and he gradually withdrew from his public engagements, ceasing his communications to the Royal Society, and advertising his desire to be excused from receiving guests, “unless upon occasions very extraordinary.” In the leisure thus gained he wished to “recruit his spirits, range his papers”, and prepare some important chemical investigations which he proposed to leave “as a kind of Hermetic legacy to the studious disciples of that art”, but of which he did not make known the nature. His health became still worse in 1691, and he died on 31 December that year, just a week after the death of the sister with whom he had lived for more than 20 years. He was buried in the churchyard of St Martin-in-the-Fields, his funeral sermon being preached by his friend Bishop Gilbert Burnet. In his will, Boyle endowed a series of lectures which came to be known as the Boyle Lectures.

Boyle’s great merit as a scientific investigator is that he carried out the principles which Francis Bacon espoused in the Novum Organum. Yet he would not avow himself a follower of Bacon, or indeed of any other teacher. On several occasions he mentions that to keep his judgment as unprepossessed as might be with any of the modern theories of philosophy, until he was “provided of experiments” to help him judge of them, he refrained from any study of the Atomical and the Cartesian systems, and even of the Novum Organum itself, though he admits to “transiently consulting” them about a few particulars. Nothing was more alien to his mental temperament than the spinning of hypotheses. He regarded the acquisition of knowledge as an end in itself. This, however, did not mean that he paid no attention to the practical application of science, but that pure knowledge was for Boyle a higher goal than applying scientific knowledge to utilitarian purposes.

Boyle was a committed alchemist, and, believing the transmutation of metals to be a possibility, he carried out experiments in the hope of achieving it. He was instrumental in obtaining the repeal, in 1689, of the statute of Henry IV against multiplying gold and silver. Despite all the important work Boyle accomplished in physics – the enunciation of Boyle’s law, the discovery of the part taken by air in the propagation of sound, and investigations on the expansive force of freezing water, on specific gravities and refractive powers, on crystals, on electricity, on color, on hydrostatics, etc. – chemistry was his favorite study. His first book, The Sceptical Chymist, published in 1661, criticized the “experiments whereby vulgar Spagyrists are wont to endeavour to evince their Salt, Sulphur and Mercury to be the true Principles of Things.” For him chemistry was the science of the composition of substances, not merely an adjunct to the arts of the alchemist or the physician. He endorsed the view that elements were the indivisible constituents of material bodies, and made the distinction between mixtures and compounds. He made considerable progress in the technique of detecting their ingredients, a process which he designated by the term “analysis”. He further supposed that the elements were ultimately composed of particles of various sorts and sizes, into which, however, they were not to be resolved in any known way. He studied the chemistry of combustion and of respiration, and conducted experiments in physiology, where, however, he was hampered by the “tenderness of his nature” which kept him from anatomical dissections, especially vivisections, though he knew them to be “most instructing”.

In addition to philosophy, Boyle devoted much time to theology, showing a very decided leaning to the practical side and an indifference to controversial polemics. At the Restoration of the king in 1660, he was favorably received at court and in 1665 would have received the provostship of Eton College had he agreed to take holy orders, but this he refused to do on the ground that his writings on religious subjects would have greater weight coming from a layman than a paid minister of the Church.

Moreover, Boyle incorporated his scientific interests into his theology, believing that natural philosophy could provide powerful evidence for the existence God. In works such as Disquisition about the Final Causes of Natural Things (1688), for instance, he criticized contemporary philosophers – such as René Descartes – who denied that the study of nature could reveal much about God. Instead, Boyle argued that natural philosophers could use the design apparently on display in some parts of nature to demonstrate God’s involvement with the world. He also attempted to tackle complex theological questions using methods derived from his scientific practices. In Some Physico-Theological Considerations about the Possibility of the Resurrection (1675), he used a chemical experiment known as the reduction to the pristine state as part of an attempt to demonstrate the physical possibility of the resurrection of the body. Throughout his career, Boyle tried to show that science could lend support to Christianity.

As a director of the East India Company he spent large sums in promoting the spread of Christianity in the East, contributing liberally to missionary societies and to the expenses of translating the Bible or portions of it into various languages. Boyle supported the policy that the Bible should be available in the vernacular language of the people. An Irish language version of the New Testament was published in 1602 but was rare in Boyle’s adult life. In 1680–85 Boyle personally financed the printing of the Bible, both Old and New Testaments, in Irish. In this respect, Boyle’s attitude to the Irish language differed from the English Ascendancy class in Ireland at the time, which was generally hostile to the language and largely opposed the use of Irish (not only as a language of religious worship).

In his will, Boyle provided money for a series of lectures to defend the Christian religion against those he considered “notorious infidels, namely atheists, deists, pagans, Jews and Muslims”, with the provision that controversies among Christians were not to be mentioned.

Boyle’s Experiments and Considerations Touching Colours has a section in it on the use of syrup of violets as a chemical indicator. The syrup is normally violet, of course, but turns red when an acid is added and green in alkaline solutions. Modern, commercial syrups of violets are of no use for experimentation because they contain artificial coloring agents precisely so that they will not change color depending on what they are mixed with. You can, however, make your own syrup. I am a huge fan of violet as a flavoring, especially for the cream centers of dark chocolates. My sister sends me half a dozen from England every Christmas.

Here’s a 17th century MS recipe for syrup of violets. Click on the image to enlarge it.

Here’s a modern recipe that works just as well.

Syrup of Violets


50g sweet violets
150ml boiling water
300gm white caster sugar


Boil a 450ml bottle in clean water to sterilize it.

Remove all green matter, including stalks, from the violets, and place them in a clean glass or ceramic bowl. Pour the boiling water over the flowers, then cover the bowl with cling film or a tea towel, and let the violets infuse overnight.

When the violets have infused, place them with their water into the top of a double boiler. Add the sugar and stir well. Bring the water in the bottom of the double boiler to a slow boil, then place the top containing the violets, sugar, and water over the boiling water. Stir the violet mixture steadily until the sugar has completely dissolved.

When the sugar has dissolved remove the mixture from the heat, and strain it through muslin lining a funnel into the sterilized bottle. Cap the bottle and store in a cool place or the refrigerator.