9. The ‘Darwinian Revolution’, The Scientists

There were many dramatic developments in science in the nineteenth century, but undoubtedly the most important of these in terms of understanding the place of humankind in the Universe (and arguably the most important idea in the whole of science) was the theory of natural selection, which, for the first time, offered a scientific explanation of the fact of evolution. The name of Charles Darwin is forever linked with the idea of natural selection, and rightly so; but two other names, Charles Lyell and Alfred Russel Wallace, deserve to stand either side of his at the centre of the evolutionary stage.

Charles Lyell came from a well-off family, but the wealth was scarcely two generations old. It originated with his grandfather, also Charles Lyell, who had been born in Forfarshire, Scotland, in 1734. This Charles Lyell was the son of a farmer, but after his father died he was apprenticed as a book-keeper before joining the Royal Navy in 1756 as an able-bodied seaman. His former training helped him to become successively a captain’s clerk, gunner’s mate and then midshipman, the first step on the road to becoming an officer. But he was not to be another Nelson, and in 1766 he became purser of HMS Romney. Fans of Horatio Hornblower and the novels of Patrick O’Brien will appreciate that the job of purser gave opportunities for even an honest man to line his pockets – the purser was responsible for purchasing supplies for his ship, which he sold at a profit to the Navy; grandfather Lyell went even further than most by joining a business partnership to supply Navy ships in the ports of North America. In 1767, he married Mary Beale, a Cornish girl, and in 1769 she gave birth (in London) to another Charles Lyell, who was to become the father of the geologist. By 1778, the elder Charles Lyell was secretary to Admiral John Byron and purser of his flagship, HMS Princess Royal. As a result of the action which Byron’s fleet saw against the French during the American War of Independence (the French navy’s assistance to the rebel cause was instrumental in ensuring that the British lost that war), Lyell received so much prize money¹ that, combining it with his other earnings, in 1782, three years after retiring from the Navy, he was able to buy estates in Scotland running to 5000 acres and including a fine house at Kinnordy, in Forfarshire (now Angus). His son had been educated in a manner fitting the elder Lyell’s growing status and spent just over a year at St Andrews University before moving to Peterhouse, Cambridge, in 1787.

The second Charles Lyell was well educated (he graduated in 1791 and then studied law in London) and well travelled, including a long tour of Europe carried out in 1792, visiting Paris when France was in the turmoil of Revolution. In 1794, he became a Fellow of Peterhouse, a useful connection for an aspiring lawyer, but he remained based in London until his father died in January 1796, in his sixty-second year. With no need now to practise law, the second Charles Lyell married a Miss Frances Smith later that year, and moved to Kinnordy, where Charles Lyell the geologist was born on 14 November 1797.

Charles and Frances Lyell never settled in Scotland, however, and before baby Charles was a year old they had moved to the south of England,² renting a large house and some land in the New Forest, not far from Southampton. It was there that young Charles grew up, surrounded by younger siblings (eventually, two brothers and no less than seven sisters). The New Forest provided a backdrop for the boy to develop an interest in botany and insects while attending school locally, but in 1810 he moved on to a minor public school at Midhurst, together with his younger brother Tom. Tom left in 1813 to become a midshipman, but Charles, as the eldest son, was groomed to follow in his father’s footsteps.

After visiting Scotland in 1815 with his parents and sister Fanny (an extended tour, but taking in the family estates he would one day inherit), Charles went up to Oxford in February 1816, joining Exeter College as a gentleman commoner, the most prestigious (and expensive) ‘rank’ of undergraduate. He took with him a reputation for academic excellence in the traditional arts-oriented subjects, and arrived at a university that was just (only just) beginning to shake off its well-deserved reputation as an institution only fit for the education of country parsons.³ Lyell found in himself an unsuspected mathematical ability and became interested in geology after he read a book in his father’s library, Robert Bakewell’s Introduction to Geology, either late in 1816 or early in 1817. Bakewell was an advocate of Hutton’s ideas, and it was through reading Bakewell that Lyell was introduced to Hutton’s work and went on to read Playfair’s book. This was the first time he had any clue that a subject like geology existed, and he then attended some lectures on mineralogy given by William Buckland (1784–1856) at Oxford in the summer term of 1817. Buckland in his turn had been inspired by the pioneering work of William Smith (1769–1839), a surveyor whose work on canals in the late eighteenth and early nineteenth centuries made him familiar with the rock strata of England and an expert in the use of fossils to indicate the relative ages of different strata (which were older and which were younger), even though there was no way at that time to tell their absolute ages. It was Smith, now regarded as the ‘father of English geology’, who produced the first geological map of England, which was published in 1815, although much of his material had already been circulated to colleagues such as Buckland. Buckland himself had been on a long geological expedition around Europe in 1816, so must have had exciting first-hand news to impart to his students, rather in the way that a university lecturer today might have returned recently from a trip abroad visiting one of the large telescopes to carry out observations of the Universe.

Lyell’s growing interest in geology did not entirely please his father, who felt that it might distract him from his study of the classics, but as well as attending Buckland’s lectures, Lyell was now drinking in the geology, on his travels around Britain (including further visits to Scotland and to East Anglia), not just admiring the fine views. In the summer of 1818, Charles Lyell senior treated the family, including Charles Lyell junior, to an extended tour of Europe. The younger Charles was able to visit the Jardin des Plantes (as it now was) in Paris, see some of Cuvier’s specimens and read Cuvier’s works on fossils in the library (Cuvier himself was in England at the time). The tour took in Switzerland and northern Italy, giving the young man ample opportunity to take in the geological delights, as well as taking in the cultural delights of cities such as Florence and Bologna. In 1819, Lyell graduated from Oxford at the age of 21, and was also elected a Fellow of the Geological Society of London (no great honour, since in those days any gentleman with an amateur interest in geology could become a Fellow, but a clear indication of where his interests lay). The next step in following in his father’s footsteps would be to study law – but the first hint of a problem that would help to change those plans came while Charles was studying hard for his final examinations, and was bothered by problems with his eyesight and severe headaches.

After another tour of England and Scotland (partly in the company of his father and sisters Marianne and Caroline), Lyell took up his legal studies in London in February 1820, but immediately he suffered more problems with his eyes, raising doubts about his ability to make his career in a profession which required minute attention to detail in handwritten documents (in an age, remember, when there was no electric light). To give his eyes a chance to recover, Charles Lyell senior took his son to Rome, via Belgium, Germany and Austria. They were away from August to November, and for a time the rest seemed to have done the trick. Lyell returned to his legal studies but continued to be troubled by his eyes, and in the autumn of 1821 paid an extended visit to the family home, Bartley, in the New Forest. In October that year he went on a leisurely tour along the South Downs, visiting his old school in Midhurst and making the acquaintance of Gideon Mantell (1790–1852) in Lewes, Sussex; Mantell was a surgeon and amateur (but very good) geologist who discovered several types of dinosaur. Lyell did go back to London and his legal studies from late October to mid-December 1821, but the combination of his eyesight problems and his love of geology meant that without any formal break with his chosen career being made, in 1822 he virtually ceased being a lawyer and began a serious investigation of the geology of the southeast of England, stimulated by his conversations and correspondence with his new friend Mantell.

Thanks to the work of people like William Smith, at that time the geological structure of England and Wales was becoming fairly well known (while the extension of related geological features into France was also being mapped), and it was obvious that rock layers had been twisted and bent, after they were laid down, by immense forces. It was natural to suppose that these forces, and the forces which had lifted what were clearly once sea beds high above sea level, were associated with earthquakes. But in spite of Hutton’s insight, the widely held opinion, championed by geologists such as William Conybeare (1787–1857), was that the changes had been brought about by short-lived, violent convulsions, and that the kind of processes now seen at work on the surface of the Earth were inadequate for the task. In the early 1820s, Lyell was intrigued by these arguments, though still more impressed by Hutton’s ideas, and learned a great deal about cutting-edge geology from Conybeare’s writings.

Lyell did actually keep up his legal studies just enough to be called to the Bar in May 1822, and later he did practise (for a short time and in a rather desultory fashion) as a barrister. But in 1823 he not only visited Paris once again (this time meeting Cuvier, still a confirmed catastrophist) but became involved in the running of the Geological Society, first as Secretary and later as Foreign Secretary; much later, he also served two terms as President. Apart from its scientific importance (Lyell attended several lectures at the Jardin, as well as meeting French scientists), the 1823 trip is significant historically because it was the first time that Lyell crossed the English channel in a steamship, the packet Earl of Liverpool, which took him direct from London to Calais in just eleven hours, with no need to wait for a fair wind. A small technological step, to be sure, but one of the first signs of the speeding up of global communications that was about to change the world.

Lyell’s own world began to change in 1825, the year that he began his practice as a barrister. He was asked to write for the Quarterly Review, a magazine published by John Murray, and began to contribute essays and book reviews (themselves really an excuse for an essay) on scientific topics and issues such as the proposal for a new university in London. He turned out to have a talent for writing, and, even better, the Quarterly paid for its contributions. Lyell’s legal work brought him very little income (it is not clear whether he actually earned enough to cover his expenses in the profession) and writing enabled him, for the first time, to achieve a degree of financial independence from his father – not that there was any pressure on him from his father to do so, but still a significant step for the young man. The Quarterly also brought Lyell’s name to the attention of a wider circle of educated people, which opened up other prospects. Having discovered his talent as a writer, early in 1827 he decided to write a book about geology and began to gather material for this project. So the idea for the book already existed, and Lyell had already proved his worth as a writer, before he set out on his most important, and famous, geological expedition, in 1828.

The expedition has echoes of John Ray’s great botanical expedition of the previous century, showing how little things had yet changed in spite of the steam packet. In May 1828, Lyell travelled first to Paris, where he had arranged to meet the geologist Roderick Murchison (1792–1871), and together they then travelled south through the Auvergne and along the Mediterranean coast to northern Italy, with Lyell making extensive notes on the geological features that they encountered. Murchison (who was accompanied by his wife) set off back to England from Padua at the end of September, while Lyell pressed on towards Sicily, the nearest location of volcanic and earthquake activity to mainland Europe. It was what Lyell saw in Sicily, in particular, that convinced him that the Earth had indeed been formed by the same processes that are at work today, operating over immense spans of time. It was Lyell’s field work that put flesh on the bones of the idea outlined by Hutton. On Etna, among other things, he found raised sea beds ‘700 feet & more’ above sea level, separated with lava flows, and in one place:

A very strong illustration of the length of the intervals which occasionally separated the flows of distinct lava currents. A bed of [fossilized] oysters, perfectly identifiable with our common eatable species, no less than twenty feet in thickness, is there seen resting on a current of basaltic lava; upon the oyster bed again is superimposed a second mass of lava, together with tuff or peperino.

…we cannot fail to form the most exalted conception of the antiquity of this mountain [Etna], when we consider that its base is about ninety miles in circumference; so that it would require ninety flows of lava, each a mile in breadth at their termination, to raise the present foot of the volcano as much as the average height of one lava-current.⁴

It was this kind of clear writing, as well as the weight of evidence he gathered in support of his case, that made Lyell’s book such an eye-opener, both to geologists and to the educated public. Lyell also realized that since Etna (and, indeed, the whole of Sicily) was relatively young, the plants and animals found there must be species that had migrated from Africa or Europe and adapted to the conditions they found. By adapting to the changing environments of our planet, life itself must be moulded in some way by geological forces, although he was unable to say just how this happened.

By February 1829, Lyell was back in London and, with his eyesight as good as it had ever been after his long journey away from his legal documents and enjoying a great deal of physical activity, he lost no time in getting down to work on his book. As well as his own field studies, Lyell drew extensively on the work of geologists from across continental Europe, producing by far the most thorough overview of the subject that anyone had yet written. John Murray, the publisher of the Quarterly, was the obvious choice to put the material before the public, and although Lyell kept rewriting his work even after it had been sent to the printers, the first volume of the Principles of Geology (a name deliberately chosen to echo Newton’s Principia) appeared in July 1830, and was an immediate success.⁵ Although Lyell often bickered with Murray about the financial side, the publisher actually treated his author well, by the standards of the day, and it was Lyell’s income from the book that eventually made him financially independent, although his father continued to provide an allowance. After more field work (this time chiefly in Spain), the second volume of the Principles appeared in January 1832 and was not only a success in its own right, but revived the sales of the first volume.

The delay between the publication of the two volumes wasn’t just caused by the field work. In 1831, a chair of geology was established at King’s College in London, and Lyell successfully sought the appointment (in spite of some opposition by Church representatives concerned about his views on the age of the Earth), giving a series of highly successful lectures (in a daring innovation, women were allowed to attend some of them), but resigning in 1833 to devote himself to his writing, which he found more profitable and in which he was his own master, with no time-consuming duties. He became the first person to make his living as a science writer (although admittedly with a little help from the family wealth).

There were other distractions. In 1831, Lyell became engaged to Mary Horner, the daughter of a geologist, Leonard Horner (1786–1864); she shared his geological interests, which made for an unusually close and happy relationship between her and Charles. The couple married in 1832, when Lyell’s allowance from his father was increased from £400 to £500 per year, while Mary brought with her investments worth £120 a year. All this, in addition to Lyell’s increasing income from writing (and the fact that they remained childless), made the couple comfortably off and made the chair at King’s an irksome distraction rather than an important source of income. Then there was politics. At the end of 1830, half a century of Tory rule came to an end in Britain and a Whig government pledged to reform Parliament came to power. These were turbulent times across Europe, and earlier in 1830 agricultural workers in England rioted in protest at the loss of work caused by the introduction of new machinery on farms. There was a distinct whiff of revolution in the air, and memories of the French Revolution were still fresh. The reforms proposed by the Whigs, which were at first popular in the country at large, included the abolition of rotten boroughs, where a few voters returned an MP to the House of Commons; but the required legislation was blocked by the House of Lords. In spite of the rottenness of the boroughs, then as now by-elections were seen as important indicators of the will of the people, and in September 1831 (when Charles Lyell happened to be at Kinnordy on holiday) a crucial by-election was held in Forfarshire. There were fewer than ninety voters in the whole of the constituency (landowners, including Charles Lyell senior and his sons) and there was no secret ballot. Every vote counted and everybody knew who had voted which way. Charles Lyell senior voted for the Tory candidate, who won by a narrow margin, while ‘our’ Charles Lyell abstained. This was a key factor in delaying the reform of Parliament, and it also had an adverse effect on the promotion prospects of Tom Lyell, now a lieutenant in the Navy, dependent on Whig patronage for promotion (since, of course, the Admiralty was run by appointees of the Whig government) but marked out as the son of a man who voted Tory at a crucial moment.

It was in the second volume of the Principles, when it eventually did appear, that Lyell turned his attention to the species puzzle, concluding that:

Each species may have had its origin in a single pair, or individual, where an individual was sufficient, and species may have been created in succession at such times and in such places as to enable them to multiply and endure for an appointed period, and occupy an appointed place on the globe.

The work, in Lyell’s view at the time, of a very ‘hands-on’ God, and not so different from the story of Noah’s Ark. Note that this hypothesis explicitly includes the idea, obvious from the fossil record by the 1830s, that many species that once lived on Earth have gone extinct and been replaced by other species. In keeping with the spirit of his times, though, Lyell reserved a special place for humankind, regarding our species as unique and distinct from the animal kingdom. But he did suggest that the reason why species went extinct was because of competition for resources, such as food, from other species.

The third volume of the Principles appeared in April 1833. Lyell’s work for the rest of his life revolved around keeping the massive book up to date, rewriting it and bringing out new editions hot on the heels of one another – the twelfth and final edition appeared posthumously in 1875, Lyell having died in London on 22 February that year (less than two years after the death of his wife), while working on what turned out to be his last revisions for the book. His Elements of Geology, which appeared in 1838 and is regarded as the first modern textbook of geology, was based on the Principles, and itself underwent refinements. This eagerness for revision wasn’t just because geology really was a fast-moving subject at the time;⁶ Lyell’s obsession with keeping the book bang up to date derived from the fact that it was his main source of income (certainly until his father died in 1849, the year of the California Gold Rush), both from its own sales and in terms of maintaining his profile as a science writer and, by general acclaim, the leading geologist of his time. Lyell was knighted in 1848 and became a baronet (a kind of hereditary knight) in 1864. Although he by no means ceased to be an active field geologist after 1833, he was then in his mid-thirties, and it was with the Principles and the Elements that he made his mark on science; there is no need to say much here about his later life, except (as we shall see) in the context of his relationship with Charles Darwin. But it is worth mentioning one of Lyell’s later geological field trips, which shows how the world was changing in the nineteenth century. In the summer of 1841, he went on a year-long visit to North America (by steamship, of course), where he not only encountered new geological evidence for the antiquity of the Earth and saw the forces of nature at work in such places as Niagara Falls, but was pleasantly surprised by the ease with which the new railways made it possible to travel across what had until very recently been unknown territory. He also gave hugely popular public lectures and boosted the sales of his books in the New World. Lyell enjoyed the experience so much that he returned for three later visits, and as a result of his first-hand knowledge of the United States became an outspoken supporter of the Union during the American Civil War (when most people of his social position in Britain supported the Confederates). But everything that Lyell did in later life was overshadowed by the Principles, and even the Principles has tended to be overshadowed in the eyes of many people by a book which, its author acknowledged, owed an enormous debt to Lyell’s book – Charles Darwin’s Origin of Species. Darwin was the right man, in the right place, at the right time to gain the maximum benefit from the Principles. But, as we shall see, this was not entirely the lucky fluke that it is sometimes made out to be.

There was nothing new about the idea of evolution by the time Charles Darwin came on the scene. Evolutionary ideas of a sort can be traced back to the Ancient Greeks, and even within the time frame covered by this book, there were notable discussions about the way species change by Francis Bacon in 1620 and a little later by the mathematician Gottfried Wilhelm Leibnitz; while in the eighteenth century, Buffon, puzzling over the way similar but subtly different species occur in different regions of the globe, speculated that North American bison might be descended from an ancestral form of European ox that migrated there, where ‘they received the impression of the climate and in time became bisons’. What was different about Charles Darwin (and Alfred Russel Wallace) was that he came up with a sound scientific theory to explain why evolution occurred, instead of resorting to vague suggestions such as the idea that it might be due to ‘the impression of the climate’. Before Darwin and Wallace, the best idea about how evolution might work (and it really was a good idea, given the state of knowledge at the time, although it has sometimes been ridiculed by those who have the benefit of hindsight) was thought up by Charles Darwin’s grandfather, Erasmus, at the end of the eighteenth century, and (independently) by the Frenchman Jean-Baptiste Lamarck at the beginning of the nineteenth century.

The association between the Darwin family and the mystery of life on Earth actually goes back one generation further still, to the time of Isaac Newton. Robert Darwin, the father of Erasmus, lived from 1682 to 1754 and was a barrister who retired from his profession and settled in the family home at Elston, in the English midlands, at the age of 42. He married the same year and Erasmus, the youngest of seven children, was born on 12 December 1731. Several years before settling into domestic bliss, however, in 1718, Robert had noticed an unusual fossil embedded in a stone slab in the village of Elston. The find is now known to be part of a plesiosaur from the Jurassic period; thanks to Robert Darwin, the fossil was presented to the Royal Society, and as a thank you, Robert was invited to attend a meeting of the Royal on 18 December that year, where he met Newton, then President of the Royal Society. Little is known about Robert Darwin’s life, but his children (three girls and four boys) were clearly brought up in a household where there was more than average curiosity about science and the natural world.

Erasmus was educated at Chesterfield School (where one of his friends was Lord George Cavendish, second son of the then Duke of Devonshire) before moving on to St John’s College, Cambridge, in 1750, partly financed by a scholarship which brought in £16 per year. In spite of the dire state of the university at the time, Erasmus did well, initially in classics, and also gained a reputation as a poet. But his father was not a rich man and Erasmus had to choose a profession where he could make a living. After his first year in Cambridge he began to study medicine; he also became a friend of John Michell, who was then a tutor at Queen’s College. His medical studies continued in Edinburgh in 1753 and 1754 (the year his father died), then he went back to Cambridge to obtain his MB in 1755. He may have spent more time in Edinburgh after that, but there is no record of him ever receiving an MD there, although this didn’t stop him from adding those letters to his list of qualifications.

Whatever his paper qualifications, Erasmus Darwin was a successful doctor who soon established a flourishing practice at Lichfield, 24 kilometres north of Birmingham. He also began to publish scientific papers (he was especially interested at the time in steam, the possibilities of steam engines and the way clouds form), and on 30 December 1757, a few weeks after his twenty-sixth birthday, he married Mary Howard (known as Polly), who was herself a few weeks short of her eighteenth birthday. All of this activity, on several fronts simultaneously, is typical of Erasmus Darwin, who certainly lived life to the full. The couple had three children who survived to adulthood (Charles, Erasmus and Robert) and two who died in infancy (Elizabeth and William). The only one who married was Robert (1766–1848), the father of Charles Robert Darwin, of evolution fame. The Charles Darwin who was Erasmus’s son was his eldest child, a brilliant student who was the apple of his father’s eye and seemed to have a glittering career ahead of him in medicine when, at the age of 20, as a medical student in Edinburgh he cut his finger during a dissection and acquired an infection (septicaemia) from which he died. By then, in 1778, Erasmus junior was already set on the path to becoming a lawyer, but young Robert was still at school and was strongly influenced by his father to become a doctor, which he did successfully, even though he lacked the brilliance of his brother and hated the sight of blood. Erasmus junior also died relatively young, drowned at the age of 40 in what may have been an accident or may have been suicide.

Polly herself had died, after a long and painful illness, in 1770. Although there is no doubt that Erasmus loved his first wife and was deeply affected by her death, when 17-year-old Mary Parker moved into the household to help look after young Robert, the inevitable happened and she produced two daughters, fathered by Erasmus. The girls were openly acknowledged as his and comfortably looked after by him in the Darwin household, even after their mother moved out and married, and everyone involved remained on friendly terms. Erasmus Darwin himself later fell for a married lady, Elizabeth Pole, and succeeded in winning her hand after her husband died; they married in 1781 and produced another seven children together, only one of whom died in infancy.

With all of this and his medical practice to tend to, you might think that Erasmus Darwin had little time for science. But he had become a Fellow of the Royal Society in 1761, was the moving force behind the establishment of the Lunar Society, and mingled with scientists such as James Watt, Benjamin Franklin (who he met through John Michell) and Joseph Priestley. He published scientific papers and kept up to date with many of the new developments in science, and was one of the first people in England to accept Lavoisier’s ideas about oxygen. He also translated Linnaeus into English (introducing the terms ‘stamen’ and ‘pistil’ to the language of botany). Along the way, he dabbled in canal investments, was one of the backers of an iron works and became firm friends with Josiah Wedgwood, who made a fortune from his pottery, and with whom Erasmus campaigned against slavery. Both men were delighted when Robert Darwin, the son of Erasmus, and Susannah Wedgwood, the daughter of Josiah, became romantically involved; but Josiah died in 1795, the year before they married. Susannah inherited £25,000 from her father, equivalent to about £2 million today, and among other things this would mean that her son Charles Robert Darwin would never have to worry about earning his living in one of the professions.

By the time Robert and Susannah married, Erasmus Darwin had achieved widespread fame for the work which justifies his place in the history of science, but this started with a poetical work, based on the ideas of Linnaeus, designed to introduce new readers to the delights of botany. It was called The Loves of the Plants, and initially published anonymously in 1789 (when Erasmus was 57), although it had had a long gestation. Erasmus literally made plants sexy, enchanted a wide audience, and seems to have been an influence on poets such as Shelley, Coleridge, Keats and Wordsworth.⁷ This success was followed in 1792 by The Economy of Vegetation (usually referred to as The Botanic Garden, which is strictly speaking the title of a collected edition including both The Economy of Vegetation and The Loves of the Plants), in which 2440 lines of verse are supported (if that is the word) by some 80,000 words of notes, which amount to a book about the natural world. Then, in 1794, Erasmus published the first volume of his prose work Zoonomia, running to more than 200,000 words and to be followed in 1796 by a second volume some 50 per cent longer still. It is in Volume 1 of Zoonomia that he at last sets out fully his ideas on evolution, alluded to in the earlier poetical writings, although these form just one chapter out of the forty in Volume 1, many of which are devoted to medicine and biology.

Erasmus Darwin’s thoughts on evolution go far beyond mere speculation and generalities, although he was, of course, handicapped by the limited state of knowledge at the time. He details the evidence that species have changed in the past, and draws particular attention to the way in which changes have been produced in both plants and animals by deliberate human intervention, for example breeding faster racehorses or developing more productive crops by the process of artificial selection – something that was to be a key feature in the theory developed by his grandson. He also points out the way in which characteristics are inherited by offspring from their parents, drawing attention to, among other things, ‘a breed of cats with an additional claw on every foot’ that he has come across. He elaborates on the way different adaptations enable different species to obtain food, mentioning (in another pre-echo of Charles Darwin) that ‘some birds have acquired harder beaks to crack nuts, as the parrot. Others have acquired beaks adapted to break the harder seeds, as sparrows. Others for the softer seeds…’. Most dramatically of all, Erasmus (clearly a Huttonian!) comes out with his belief that all of life on Earth (by implication including humankind) may be descended from a common source:

Would it be too bold to imagine, that in the great length of time since the earth began to exist, perhaps millions of ages⁸ before the commencement of the history of mankind, would it be too bold to imagine, that all warm-blooded animals have arisen from one living filament, which THE GREAT FIRST CAUSE endued with animality, with the power of acquiring new parts, attended with new propensities…

God still exists for Erasmus, but only as the first cause who set the processes of life on Earth working; there is no place here for a God who intervenes to create new species from time to time, but a clear sense that whatever the origins of life itself, once life existed it evolved and adapted in accordance with natural laws, with no outside intervention.⁹ But Erasmus did not know what those natural laws that govern evolution were. His speculation was that changes were brought about in the bodies of living animals and plants by their striving for something they needed (food, say) or to escape from predators. This would be rather like the way in which a weight lifter puts on muscle. But Erasmus thought that these acquired characteristics would then be passed on to the offspring of the individual that acquired them, leading to evolutionary change. A wading bird that didn’t like getting its feathers wet, for example, would constantly be stretching up as high as possible to avoid contact with the water, and thereby stretch its legs a tiny bit. The slightly longer legs would be inherited by its offspring, and over many generations this repeating process could turn a bird with legs like a swan into one with legs like a flamingo.

Although this idea was wrong, it was not crazy, given the state of knowledge at the end of the eighteenth century, and Erasmus Darwin deserves credit for at least trying to come up with a scientific explanation for the fact of evolution. He continued (along with many other activities) to develop his ideas for the rest of his life, and 1803 saw the publication of The Temple of Nature, which told in verse of the evolution of life from a microscopic speck to the diversity of the present day. Once again, the verse is accompanied by copious notes that amount to a book in their own right. But this time Erasmus did not meet with publishing success; his near atheism and evolutionary ideas were condemned, and were clearly out of step with a society at war with Napoleonic France and longing for stability and security rather than revolution and evolution. Besides, Erasmus himself was no longer around to argue his cause, having died quietly at home on 18 April 1802, at the age of 70. Perhaps appropriately, though, given the political situation, it was indeed in Napoleonic France that similar evolutionary ideas to those of Erasmus Darwin were taken up and developed, in some ways more fully.

Jean-Baptiste Pierre Antoine de Monet de Lamarck, to give him his full entitlement of names, was a member of the minor French nobility (it is a reasonable rule of thumb that the longer the list of names, the more minor the branch of the nobility), born at Bazentin, in Picardy, on 1 August 1744. He was educated at the Jesuit College in Amiens from about the age of 11 to 15 (details of his early life are rather vague), and was probably intended for the priesthood. But when his father died in 1760 he set off to become a soldier, joining the army fighting in the Low Countries during the Seven Years War. The war ended in 1763, and Lamarck seems to have become interested in botany as a result of the wildlife he saw on subsequent postings to the Mediterranean and eastern France. In 1768, he received an injury which forced him to give up his military career, and he settled in Paris, where he worked in a bank and attended lectures on medicine and botany. Ten years later, he established his reputation as a botanist with the publication of his Flore française (French Flora), which became the standard text on the classification of French plants. On the strength of the book (and with the patronage of Buffon, who had helped with the book’s publication), Lamarck was elected to the Académie and was soon able to turn his back on the bank.

Buffon’s patronage came at a price. In 1781, Lamarck had the unenviable task of acting as tutor and companion to Buffon’s useless son Georges during a European tour; but at least this gave Lamarck an opportunity to see more of the natural world. After his travels, Lamarck held a series of minor botanical posts connected with the Jardin du Roi, although his interests extended far beyond botany (or even biology) and included meteorology, physics and chemistry. He was involved in the reorganization of the Jardin after the French Revolution and was assigned responsibility, as a professor, for the study of what were then called ‘insects and worms’ in the new French Natural History Museum in 1793; it was Lamarck who gave this rag-bag collection of species the overall name ‘invertebrates’. As a reformer, and untainted by any odious connections with tax farming, Lamarck seems to have survived the Revolution without ever being personally threatened. As a professor, Lamarck was required to give an annual series of lectures at the museum, and these lectures show how his ideas on evolution themselves gradually evolved, with the first mention of the idea that species are not immutable coming in 1800. Describing animals from the most complex forms downwards to the simplest, classified by what he (rather confusingly) called their ‘degradation’, he said that the invertebrates:

show us still better than the others that astounding degradation in organization, and that progressive diminution in animal faculties which must greatly interest the philosophical Naturalist. Finally they take us gradually to the ultimate stage of animalization, that is to say to the most imperfect animals, the most simply organized, those indeed which are hardly to be suspected of animality. These are, perhaps, the ones with which nature began, while it formed all the others with the help of much time and of favourable circumstances.¹⁰

In other words, although his argument is presented upside down, Lamarck is saying that the simplest animals evolved into the more complex – and note that reference to ‘much time’ being required for the process.

Lamarck’s biographer L. J. Jordanova says that there is ‘no evidence’ that he was aware of the ideas of Erasmus Darwin; Darwin’s biographer Desmond King-Hele says that Lamarck’s ideas were ‘almost certainly’ influenced by Zoonomia. We shall never know the truth, but in one respect Lamarck’s behaviour was very similar to that of Darwin. Although little is known of his private life, we do know that he had six children by a woman he lived with, and married her only when she was dying. He then married at least twice more (there is some suggestion of a fourth marriage) and produced at least two more children. But unlike Erasmus Darwin (or, indeed, Charles Darwin) he had an abysmal literary style and seems (as the above example, which is far from being the worst, shows) to have been unable to present his ideas clearly in print.

Those ideas on evolution were summed up in his epic Histoire naturelle des animaux sans vertèbres, published in seven volumes between 1815 and 1822, when Lamarck was 78 and blind (he died in Paris on 18 December 1829). For our purposes, Lamarck’s ideas on evolution can be summed up by the four ‘laws’ which he presented in Volume 1 of that book, published in 1815:

First Law: By virtue of life’s own powers there is a constant tendency for the volume of all organic bodies to increase and for the dimensions of their parts to extend up to a limit determined by life itself.

(This is more or less true; there does seem to be some evolutionary advantage in having a bigger body, and most multi-celled animal species have got bigger in the course of evolution.)

Second Law: The production of new organs in animals results from newly experienced needs which persist, and from new movements which the needs give rise to and maintain.

(At the very least this is not completely wrong; if the environmental circumstances change, there are pressures which favour certain evolutionary developments. But Lamarck means, wrongly, that the ‘new organs’ develop within individuals, not by tiny changes from one generation to the next.)

Third Law: The development of organs and their faculties bears a constant relationship to the use of the organs in question.

(This is the idea that the flamingo’s legs get longer because the flamingo is always stretching up to avoid contact with the water. Definitely wrong.)

Fourth Law: Everything which has been acquired…or changed in the organization of an individual during its lifetime is preserved in the reproductive process and is transmitted to the next generation by those who experienced the alterations.

(This is the heart of Lamarckism – the inheritance of acquired characteristics. Definitely wrong.)

Perhaps the most telling point made by Lamarck, though, was the one which stuck in the throat of Charles Lyell and led him to reject the idea of evolution when writing the Principles – he specifically included humankind in the process.

Lamarck’s ideas were strongly opposed by the influential Georges Cuvier, who firmly believed in the fixity of species, and were promoted by Isidore Geoffroy Saint-Hilaire (1772–1844), who worked with Lamarck in Paris. Unfortunately, Saint-Hilaire’s support did at least as much harm to the Lamarckian cause as it did good. He built from Lamarck’s ideas and came very close to the idea of natural selection, suggesting that the kind of ‘new organs’ described by Lamarck might not always be beneficial and writing (in the 1820s) that:

If these modifications lead to injurious effects, the animals which exhibit them perish and are replaced by others of a somewhat different form, a form changed so as to be adapted to the new environment.¹¹

This includes elements of Lamarckism, but also the germ of the idea of survival of the fittest. But Saint-Hilaire also espoused wild ideas about the relationships between species, and although he did a great deal of sound comparative anatomy he went too far when he claimed to have identified the same basic body plan in vertebrates and molluscs, drawing further fire from Cuvier and discrediting all his work, including his ideas on evolution. By the end of the 1820s, with Lamarck dead and his main supporter to a large extent discredited, the way was clear for Charles Darwin to pick up the threads. But it took him a long time to weave those threads into a coherent theory of evolution, and even longer to get up the nerve to publish his ideas.

There are two popular myths about Charles Darwin, neither of which resembles the truth. The first, already alluded to, is that he was a dilettante young gentleman who was lucky enough to go on a voyage around the world, where he saw the rather obvious evidence for evolution at work and came up with an explanation that any reasonably intelligent contemporary might have thought of in the same circumstances. The second is that he was a rare genius whose unique flash of insight advanced the cause of science by a generation or more. In fact, both Charles Darwin and the idea of natural selection were very much products of their time, but he was unusually hard working, painstaking and persistent in his search for scientific truth across a wide range of disciplines.

By the time Erasmus Darwin died, his son Robert was well established in a successful medical practice near Shrewsbury, and had recently moved into a fine house that he had had built, called The Mount and completed in 1800. Robert resembled his father physically, over six feet tall and running to fat as he grew older; in the Darwin tradition, he fathered a healthy brood of children (although not quite on the scale that his father had), but Erasmus did not live to see the birth of his grandson Charles, who was the second-youngest of that brood. His sisters Marianne, Caroline and Susan were born in 1798, 1800 and 1803, elder brother Erasmus in 1804, Charles Robert Darwin on 12 February 1809 and finally Emily Catherine (known to the family as Catty) arrived in 1810, when her mother Susannah was 44. Charles seems to have had an idyllic childhood, spoiled by three older sisters, allowed to roam the grounds of the house and nearby countryside, taught the basics of reading and writing at home by Caroline until he was eight years old, and with an elder brother to look up to. Things changed dramatically in 1817. In the spring of that year, Charles began attending a local day school, prior to becoming a boarder at Shrewsbury School (where his brother Erasmus was already established) in 1818. And in July 1817, after a life troubled by illness of one kind or another, his mother died, taken by a sudden and painful intestinal complaint at the age of 52. Robert Darwin never came to terms with his loss, and far from following his father’s example of a happy second marriage, he forbade any discussion of his lost wife and sank into frequent bouts of depression for the rest of his life. His edict must have carried weight, since in later life Charles Darwin wrote that he could recall very little of his mother.

As far as running the household was concerned, Marianne and Caroline were old enough to take over, and the younger daughters later played their part. Some historians (and psychologists) argue that his mother’s death, and especially his father’s response to it, must have had a profound impact on young Charles and shaped his future personality; others suggest that in a large household with several sisters and servants, his mother was a more remote figure than would be the case for an 8-year-old today, and that her death probably left no lasting scars. But the fact that Charles was sent away to boarding school just a year after his mother died, cutting him off from that supportive family environment (but bringing him closer to his brother Erasmus), suggests that the combination of factors in 1817 and 1818 really did have a profound impact on him. Shrewsbury School was close enough to The Mount – just 15 minutes away across the fields, making relatively frequent visits home quite feasible – but to a 9-year-old boy living away from home for the first time it made little difference whether home was 15 minutes’ or 15 days’ journey away.

Darwin developed a strong interest in natural history during his time at Shrewsbury School, taking long walks to observe his natural surroundings,¹² collecting specimens and poring over books in his father’s library. In 1822, when Erasmus was in his final year at the school and Charles was 13, the elder brother developed a short-lived but passionate interest in chemistry (a very fashionable subject at the time) and easily persuaded Charles to act as his assistant in setting up a laboratory of their own at The Mount, funded to the tune of £50 with the aid of their indulgent father. When Erasmus duly left to go up to Cambridge later that year, Charles had the run of the lab to himself whenever he was at home.

Erasmus was following in the family tradition, training to become a doctor, but had no vocation for the profession and found the academic routine at Cambridge boring, but the extra-curricular activities much more to his taste. Charles found life at Shrewsbury School without Erasmus equally dull, but made up for it when he was allowed to visit Erasmus in the summer of 1823, having what could only be described as a high old time, which had a distinctly bad influence on the 14-year-old. Back home he developed a passion for shooting game birds, preferred sports to academic work at school and was so clearly showing signs of becoming a wastrel younger son that in 1825 Robert Darwin took him out of school and made him his own assistant for a few months, trying to instil in him something of the Darwin medical tradition. He was then packed off to Edinburgh as a medical student. Although Charles was only 16, Erasmus had just completed his three years in Cambridge and was himself about to spend a year in Edinburgh to complete his medical training; the idea was that Charles could be looked after by Erasmus and attend medical courses during that year, after which he would be settled enough and old enough (hopefully, mature enough) to work formally for his medical qualifications on his own. But it didn’t work out like that.

In many ways, the year in Edinburgh was a rerun of the high old time in Cambridge, although Erasmus managed to scrape through his courses and the two young men managed to avoid any detailed reports of their extra-curricular activities getting back to Dr Robert. Any possibility that Charles might himself become a doctor disappeared, however, not through neglect of his studies but through his own squeamishness. Although made physically sick by dissection of a corpse, Charles did stick to certain aspects of his studies. But the turning point came when he watched two operations, one on a child, being carried out, as was the only way possible then, without anaesthetic. The image of the screaming child, in particular, made a deep impression on him, and he later wrote in his Autobiography:

I rushed away before they were completed. Nor did I ever attend again, for hardly any inducement would have been strong enough to make me do so; this being long before the blessed days of chloroform.

Unable to bring himself to admit this failing to his father, Darwin returned to Edinburgh in October 1826, ostensibly to continue his medical studies, but enrolled in classes in natural history, attended lectures on geology and in particular came under the influence of Robert Grant (1793–1874), a Scottish comparative anatomist and expert on marine life who was fascinated by sea slugs. Grant was an evolutionist who favoured Lamarckism and also shared some of Saint-Hilaire’s views about the universal body plan; he passed these ideas on to young Darwin (who had already read Zoonomia for its medical insights, although, according to his autobiography, without the evolutionary ideas in it making any impact on him at the time) and encouraged him to do his own studies of the creatures they found on the sea shore. In geology, Darwin learned about the argument between the Neptunists, who thought that the Earth’s features had been shaped by water, and the Vulcanists, who saw heat as the driving force (he preferred the latter explanation). But by April 1827, although Darwin (still only 18) had found something he was deeply interested in and prepared to work hard at, it was clear that the sham of his medical studies could not be sustained and he left Edinburgh for good, with no formal qualifications. Perhaps in order to delay the inevitable confrontation with his father, he took his time getting back to The Mount. After a short tour of Scotland he went on his first visit to London, where he met up with his sister Caroline and was shown around by his cousin Harry Wedgwood, newly qualified as a barrister. He then moved on to Paris, meeting up with Josiah Wedgwood II (Harry’s father, and the son of the close friend of Charles’s grandfather Erasmus) and his daughters Fanny and Emma, on their way back to England from Switzerland.

In August, however, it was time to face the music, and the upshot was that Robert Darwin insisted that the only prospect was for Charles to go up to Cambridge and obtain his degree, so that Robert could set him up as a country clergyman, the standard respectable way of disposing of rapscallion younger sons at the time. After a summer divided between the country pursuits of the rich (hunting and partying) and cramming rather desperately to bring his knowledge of the classics up to scratch, Charles Darwin was formally accepted by Christ’s College in the autumn of 1827, and took up residence, after more swotting, early in 1828. Once again, he was in the company of Erasmus, now finishing his Bachelor of Medicine degree before setting off on a Grand Tour of Europe as a reward. The contrast for Charles, who faced four years’ study and a life as a country parson, must have been hard to swallow.

Darwin’s time as an undergraduate in Cambridge followed the pattern he had established in his later months in Edinburgh; he neglected his official studies but threw himself into the study of what really interested him – the natural world. This time, he came under the wing of John Henslow (1795–1861), professor of botany in Cambridge, who became a friend as well as a teacher. He also studied geology under Adam Sedgwick (1785–1873), the Woodwardian professor of geology, who was outstanding at field work, although he rejected the uniformitarian ideas of Hutton and Lyell. Both men regarded Darwin as an outstanding pupil, and his intellectual capacity and ability for hard work were demonstrated when, after a desperate burst of last-minute cramming to catch up on all the things he had been neglecting while out botanizing and geologizing, Darwin surprised even himself by obtaining a very respectable degree (tenth out of 178) in the examinations held at the beginning of 1831. But in spite of the scientific ability he had shown, the route to a country parsonage now seemed more clear-cut than ever, not least since while Charles had been up at Cambridge, Erasmus had managed to persuade their father that he was not suited to the medical life and had been allowed to abandon his career at the age of 25 and settle in London with an allowance from Dr Robert. Indulgent the doctor might be, but he naturally wanted at least one of his sons to settle down at a respectable profession.

Charles spent the summer of 1831 on what he must have thought would be his last great geological expedition, studying the rocks of Wales, before returning to The Mount on 29 August. There, he found a totally unexpected letter from one of his Cambridge tutors, George Peacock. Peacock was passing on an invitation from his friend Captain Francis Beaufort (1774–1857), of the Admiralty (and now famous for the wind scale that bears his name), inviting Darwin to join a surveying expedition to be carried out by HMS Beagle, under the command of Captain Robert FitzRoy, who was looking for a suitable gentleman to accompany him on the long voyage and take advantage of the opportunity to study the natural history and geology of, in particular, South America. Darwin’s name had been suggested by Henslow, who also sent a letter urging him to seize the opportunity. Darwin was not actually the first choice for the position – Henslow thought briefly of taking the opportunity himself, and another of his protégés turned it down in favour of becoming vicar of Bottisham, a village just outside Cambridge. But he absolutely had the right credentials – FitzRoy wanted a gentleman, a member of his own class, who he could treat on equal terms during the long voyage, when he would otherwise be isolated from social contact by his God-like position in command. The gentleman had (of course) to pay his own way; and the Admiralty were keen that he should be an accomplished naturalist to take advantage of the opportunities offered by the expedition to South America and (possibly) around the world. When Henslow suggested Darwin (via Peacock) to Beaufort, though, the name struck an additional chord. One of grandfather Erasmus Darwin’s close friends had been Richard Edgeworth, a man after his own heart who had four happy marriages and produced 22 children. Twelve years younger than Erasmus, Edgeworth had married for the fourth and last time in 1798, to a Miss Frances Beaufort, the 29-year-old sister of the Francis Beaufort, who by 1831 was Hydrographer to the Royal Navy. So when Beaufort wrote to FitzRoy recommending young Charles for the role of companion and naturalist on the voyage, he was happy to describe him as ‘a Mr Darwin grandson of the well known philosopher and poet – full of zeal and enterprize’ even though the two had never met.¹⁴

There were some hurdles to overcome before Darwin’s role on the Beagle was finalized. At first, his father (who would have to fund young Charles on the trip) objected to what seemed to be another madcap scheme, but was won over by Josiah Wedgwood II, Charles Darwin’s uncle. Then, FitzRoy (a temperamental man) took exception to the way Darwin seemed to be being foisted on him, sight unseen, and darkly suggested that he might have already found his own companion; things were smoothed out when Darwin and FitzRoy met and hit it off with one another. Eventually all was settled, and the Beagle, a three-masted vessel just 90 feet (27 metres) long, set sail on 27 December 1831, when Charles Darwin was not quite 23 years old. There is no need to go into details of the five-year-long voyage (which did indeed go right around the world) here, but there are a few points worth mentioning. First, Darwin was not cooped up on the ship for all that time, but went on long expeditions through South America, in particular, while the ship was busy at the official surveying work. Second, he made his name in scientific circles as a geologist, not as a biologist, through the fossils and other samples that he sent back to England during the voyage. And finally, there is one particular detail worth mentioning – Darwin experienced a large earthquake in Chile and saw for himself how much the disturbance had raised the land, with shellfish beds stranded high and dry several feet (about a metre) above the shoreline. This was first-hand confirmation of the ideas spelled out by Lyell in his Principles of Geology. Darwin had taken the first volume with him on the voyage, the second caught up with him during the expedition and the third was waiting for him on his return to England in October 1836. Seeing the world through Lyell’s eyes, he became a confirmed uniformitarian, and this had a profound influence on the development of his ideas on evolution – as Darwin put it late in his life:

I always feel as if my books came half out of Lyell’s brain, and that I have never acknowledged this sufficiently…I have always thought that the great merit of the Principles was that it altered the whole tone of one’s mind.¹⁵

Darwin came home to a reception he can scarcely have dreamed of, and which must have both puzzled and gratified his father. He soon met Lyell himself, and was introduced as an equal to the geological luminaries of the land. In January 1837 he read a paper to the Geological Society of London on the coastal uplift in Chile (the hottest discovery from his voyage) and was almost immediately elected a Fellow of the Society (significantly, he did not become a Fellow of the Zoological Society until 1839, the same year that he was elected a Fellow of the Royal Society). As well as his fame as a geologist, Darwin soon also received acclaim as a writer, in the mould of Lyell. The first project was a Journal of Researches,¹⁶ in which Darwin wrote about his activities on the voyage, while FitzRoy wrote about the more naval aspects. Darwin soon completed his share of the work, drawing on his diaries, but publication was delayed until 1839 because of FitzRoy’s naval commitments, which left him little time for writing – and also, to be frank, because FitzRoy wasn’t very good at writing. To FitzRoy’s chagrin, it soon became clear that Darwin’s part of the book was of much wider interest than his own, and it was quickly republished on its own as the Voyage of the Beagle.

1839 was a big year in Darwin’s life – the year he turned 30, saw the publication of the Journal, became a Fellow of the Royal Society and married his cousin Emma Wedgwood. It was also smack in the middle of what he later described as his most creative period intellectually, from the return of the Beagle in 1836 to the time he left London and settled with his new family in Kent, in 1842. But it was also during this period that he began to suffer a series of debilitating illnesses, the exact cause of which has never been ascertained, but which in all probability resulted from a disease picked up in the tropics. The move out of London, where Darwin had initially settled on his return to England, resulted in no small measure from the political turmoil of the time, with reformers such as the Chartists demonstrating on the streets of the capital and kept in check by the army. The Darwins moved to Down House, in the village of Down, in Kent (the village later changed its name to Downe, but the house kept the old spelling).

Charles and Emma had a long and happy marriage, blighted only by his recurring illness and the early deaths of several of their children. But they also produced many survivors, some of whom went on to achieve eminence in their own right. William, the first-born, lived from 1839 to 1914; then came Anne (1841–1851), Mary (died aged three weeks, 1842), Henrietta (1843–1930), George (1845–1912), Elizabeth (1847–1926), Francis (1848–1925), Leonard (1850–1943), Horace (1851–1928) and Charles (1856–1858). It’s worth looking again at those dates for Leonard; born well before the publication of the Origin, he lived until well after the atom had been split, which gives some idea of the pace of change of science in the hundred years from 1850 to 1950. But the family life, except as a stable background for Charles Darwin’s work, is not what matters here. What we are interested in is Darwin’s work, and especially the theory of evolution by natural selection.

There was no question in Darwin’s mind by the time he returned from his voyage (if not before he set out) that evolution was a fact. The puzzle was to find a natural mechanism that would explain that fact – a model, or theory, of how evolution worked. Darwin started his first notebook on The Transformation of Species in 1837, and developed his evolutionary ideas privately while publishing geological papers that proved crucial in deciding the uniformitarian/Catastrophist debate in favour of the Uniformitarians. A key step came in the autumn of 1838, not long before his marriage, when Darwin read the famous Essay on the Principle of Population by Thomas Malthus (1766–1834).¹⁷ Originally published anonymously in 1798, the essay was in a sixth (by now signed) edition by the time Darwin read it. Malthus himself, who studied at Cambridge and was ordained in 1788, wrote the first version of the essay while working as a curate, but later became a famous economist and Britain’s first professor of political economy. He pointed out in his essay that populations, including human populations, have the power to grow geometrically, doubling in a certain interval of time, then doubling again in the next interval the same size, and so on. At the time he was writing, the human population of North America really was doubling every twenty-five years, and all that is required to achieve this is that, on average, each couple should, by the time they are 25, have produced four children who in turn survive to be 25. The fecundity of the Darwin family must have immediately brought home to Charles how modest a requirement this is.

Indeed, if each pair of even the slowest-breeding mammals, elephants, left just four offspring that survived and bred in their turn, then in 750 years each original pair would have 19 million living descendants. Yet clearly, as Malthus pointed out, there were about the same number of elephants around at the end of the eighteenth century as there had been in 1050. He reasoned that populations are held in check by pestilence, predators and especially by the limited amount of food available (as well as by war, in the case of humans), so that on average each pair leaves just two surviving offspring, except in special cases like the opening up of new land for colonization in North America. Most offspring die without reproducing, if nature takes its course.

Malthusian arguments were actually used by nineteenth-century politicians to argue that efforts to improve the lot of the working classes were doomed to failure, since any improvements in living conditions would result in more children surviving and the resulting increase in population would swallow up the improved resources to leave even more people in the same abject state of poverty.¹⁸ But Darwin, in the autumn of 1838, leaped to a different conclusion. Here were the ingredients of a theory of how evolution could work – pressure of population, struggle for survival among members of the same species (more accurately, of course, it is a struggle to reproduce) and survival (reproduction) only of the best-adapted individuals (the ‘fittest’, in the sense of the fit of a key in a lock, or a piece in a jigsaw puzzle, rather than the sporting sense of the word).

Darwin sketched out these ideas in a document dated by historians to 1839, and more fully in a 35-page outline dated by himself to 1842. The theory of evolution by natural selection was essentially complete before he even moved to Down House, and he discussed it with a few trusted colleagues, including Lyell (who, to Darwin’s disappointment, was not convinced). Afraid of the public reaction to the theory, and worried about upsetting Emma, a very conventional Christian, Darwin then sat on the idea for two decades, although in 1844 he did develop his outline into a manuscript about 50,000 words long, running to 189 pages, which he had copied out neatly by a local schoolmaster and left among his papers, with a note to Emma requesting that it be published after his death.

Or rather, he didn’t quite sit on it. In the second edition of the Voyage of the Beagle, which he worked on in 1845, Darwin added a lot of new material, scattered here and there through the pages. Howard Gruber has pointed out that it is easy to identify these paragraphs by comparing the two editions, and that if you take all the new material out and string it together, it forms ‘an essay which gives almost the whole of his thought’ on evolution by natural selection.¹⁹ The only explanation is that Darwin was concerned about posterity, and about his priority. If anyone else came up with the idea, he could point to this ‘ghost’ essay and reveal that he had thought of it first. Meanwhile, in order to make it more likely that his theory would be accepted when he did eventually get around to publishing it, he decided that he ought to make a name for himself as a biologist. Starting in 1846 (ten years after the Beagle had brought him home), he began an exhaustive study of barnacles, drawing in part on his South American materials, that eventually formed a definitive, three-volume work completed in 1854. It was a stunning achievement for a man with no previous reputation in the field, often wracked by illness, during a period which also saw the death of his father in 1848 and of his favourite daughter, Annie, in 1851. It earned him the Royal Medal of the Royal Society, their highest award for a naturalist. He was, for the first time, established as a biologist of the first rank, with a thorough understanding of the subtle differences between closely related species. But he still hesitated about publishing his ideas on evolution, although, at the urging of the few close confidants with whom he discussed the idea, he began, in the mid-1850s, to collect his material together and organize it into what he planned would be a big, fat book that would present such a weight of evidence that it would overwhelm any opposition. ‘From September 1854 onwards,’ he wrote in his Autobiography, ‘I devoted all my time to arranging my huge pile of notes, to observing, and experimenting, in relation to the transmutation of species.’ It is doubtful if such a book would ever have seen the light of day in Darwin’s lifetime, but he was finally forced to go public when another naturalist did indeed come up with the same idea.

The ‘other man’ was Alfred Russel Wallace, a naturalist based in the Far East, who in 1858 was 35 years old, the same age that Darwin had been in 1844, when he developed the extended outline of his theory. The contrast between Darwin’s privileged life and Wallace’s own struggle for survival is striking, and worth highlighting as an example of how science at this time was ceasing to be the prerogative of the wealthy gentleman amateur. Wallace was born at Usk, in Monmouthshire (now Gwent), on 8 January 1823. He was the eighth out of nine children of an ordinary family; his father was a rather unsuccessful solicitor and the children were given a basic education at home by him. In 1828, the family moved briefly to Dulwich, then settled in Hertford, the home town of Alfred’s mother. There, Alfred and one of his brothers, John, attended the local grammar school, but Alfred had to leave at about the age of 14 to earn a living. In his autobiography My Life, published in 1905, Wallace said that school made little impact on him, but that he read voraciously from his father’s large collection of books and from the books that became available to him when his father ran a small library in Hertford. In 1837 (with Darwin already returned from his famous voyage), Wallace went to work with his eldest brother William, a surveyor. He revelled in the open-air life, fascinated by the different kinds of rock strata being uncovered by canal- and road-building work, and intrigued by the fossils revealed in the process. But the money and prospects in surveying were poor at that time and Wallace briefly became apprenticed to a clockmaker, only giving up the trade because the clockmaker moved to London and he didn’t want to follow. So it was back to surveying with William, this time as part of the programme of land enclosure in mid-Wales – Wallace didn’t appreciate the political implications at the time, but later railed about this ‘land-robbery’.²⁰ The brothers also turned their hands to building, designing the structures themselves, seemingly successfully, even though they had no training in architecture and relied on what they could learn from books. But all the while, Alfred Wallace was becoming more interested in the study of the natural world, reading appropriate books and beginning a scientific collection of wild flowers.

These relatively good times came to an end in 1843, when Alfred’s father died and the surveying work dried up as the country was gripped by an economic recession (by now, Darwin had settled in Down House and had already written down at least two outlines of the theory of natural selection). Alfred lived for a few months in London with his brother John (a builder), surviving on a small inheritance. When that ran out in 1844, he managed to get a job at a school in Leicester, teaching the basics of reading, writing and arithmetic to the youngest boys, and surveying (which was probably the key to him getting the job, since anyone could teach the ‘three Rs’) to older boys. His salary was £30 a year, which puts the £50 spent by young Charles and Erasmus Darwin on setting up their home chemical laboratory in perspective. Wallace was now 21, just a year younger than Darwin had been when he graduated from Cambridge, in a dead-end job, with no prospects. But two significant events occurred during his time in Leicester. He read Malthus’s Essay for the first time (although it did not initially have a dramatic impact on his thinking) and he met another keen amateur naturalist, Henry Bates (1825–1892), whose interest in entomology neatly complemented Wallace’s interest in flowers.

Wallace was rescued from a life as a (by his own admission) second-rate schoolmaster by a family tragedy. In February 1845, his brother William died from pneumonia, and after settling William’s affairs, Alfred decided to take over his surveying work, based in the town of Neath, in South Wales. This time he was lucky; there was plenty of work connected with the railway boom of the time and Alfred was quickly able to build up a small capital fund, for the first time in his life. He brought his mother and brother John to live with him in Neath, and with John’s help once again branched out into architecture and building work. His interest in natural history also flourished and was boosted by correspondence with Bates. But Wallace became increasingly frustrated and disillusioned by the business side of the surveying and building work, finding it difficult to cope with businesses which owed him money but delayed payment, and getting depressed when sometimes confronted by smaller creditors who genuinely could not afford to pay. After a visit to Paris in September 1847, when he visited the Jardin des Plantes, Wallace hatched a scheme to change his life once and for all, and proposed to Bates that they should use the small amount of money that Wallace had accumulated to finance a two-man expedition to South America. Once there, they could fund their natural history work by sending back specimens to Britain to be sold to museums and to the wealthy private collectors who were then (partly thanks to Darwin’s account of the voyage of the Beagle) always on the lookout for curiosities from the tropics. Already a firm believer in evolution, Wallace said in his autobiography that even before setting out on this expedition, ‘the great problem of the origin of species was already distinctly formulated in my mind…I firmly believed that a full and careful study of the facts of nature would ultimately lead to a solution of the mystery’.

Some four years spent exploring and collecting in the jungles of Brazil, often under conditions of extreme hardship, gave Wallace the same sort of first-hand experience of the living world that Darwin had gained during the voyage of the Beagle, and helped him to establish a reputation as a naturalist through papers published as a result of his work in the field, as well as through the specimens he collected. But the expedition was far from being a triumph. Alfred’s younger brother Herbert, who travelled out to Brazil to join him in 1849, died of yellow fever in 1851, and Alfred always blamed himself for his brother’s death, on the grounds that Herbert would never have gone to Brazil if Alfred had not been there. Alfred Wallace himself nearly died as a result of his South American adventure. On the way home, the ship he was travelling on, the brig Helen, carrying a cargo of rubber, caught fire and went to the bottom, taking Wallace’s best specimens with her. The crew and passengers spent ten days at sea in open boats before being rescued, and Wallace returned to England late in 1852 almost penniless (although he had had the foresight to insure his collection for £150), with nothing to sell, but with notes which he used as the basis for several scientific papers and a book, Narrative of Travels in the Amazon and Rio Negro, which was modestly successful. Bates had stayed in South America and returned three years later, with his specimens intact; but by then Wallace was on the other side of the world.

During the next sixteen months, Wallace attended scientific meetings, studied insects at the British Museum, found time for a short holiday in Switzerland and planned his next expedition. He also met Darwin at a scientific gathering early in 1854, but neither of them could later recall any details of the occasion. More significantly, the two began a correspondence, resulting from Darwin’s interest in a paper by Wallace on the variability of species of butterfly in the Amazon basin; this led to Darwin becoming one of Wallace’s customers, buying specimens that he sent back from the Far East, and sometimes complaining (gently) in his notes about the cost of shipping them back to England. Wallace went to the Far East because he decided that the best way to pursue his interest in the species problem would be to visit a region of the globe which had not already been explored by other naturalists, so that the specimens he sent home would be more valuable (both scientifically and financially), and the income from them could support him adequately. His studies at the British Museum, and conversations with other naturalists, convinced him that the Malay Archipelago fitted the bill, and he scraped together enough money to set out²¹ in the spring of 1854, some six months before Darwin started arranging his ‘huge pile of notes’, this time accompanied by a 16-year-old assistant, Charles Allen.

This time, Wallace’s expedition was an unqualified success, although once again he endured the hardships of travelling in tropical regions where few Westerners had yet been. He was away for eight years, during which time he published more than forty scientific papers, sent back to the journals in England, and he returned with his specimen collections intact. Apart from his ideas on evolution, his work was extremely important in establishing the geographical ranges of different species, which showed how they had spread from one island to another (later, such work would tie in with the idea of continental drift). But, of course, it is evolution that concerns us here. Influenced, like Darwin, by the work of Lyell, which established the great age of the Earth (what Darwin once called ‘the gift of time’) and the way an accumulation of small changes could add up to produce large changes, Wallace developed the idea of evolution as like the branching of a huge tree, with different branches growing from a single trunk, and continually dividing and splitting down to the little twigs, still growing, which represent the diversity of living species (all derived from a common stock) in the world today. He presented these ideas in a paper published in 1855, without, at that point, offering an explanation for how or why speciation (the splitting of the branches into two or more closely related growing twigs) occurred.

Darwin and his friends welcomed the paper, but several, including Lyell, soon became concerned that Darwin might be pre-empted, by Wallace or somebody else, if he did not publish soon (Lyell still wasn’t convinced about natural selection, but as a friend and a good scientist he wanted the idea in print, to establish Darwin’s priority and stir a wider debate). The climate of opinion was much more favourable to open debate about evolution than it had been twenty years before, but Darwin still failed to see any urgency and carried on sorting his vast weight of evidence in support of the idea of natural selection. He did drop hints in his correspondence to Wallace that he was preparing such a work for publication, but gave no details of the theory; they were intended to warn Wallace that Darwin was ahead of him in this particular game. But they had the effect of encouraging Wallace and stimulating him to develop his own ideas further.

The breakthrough came in February 1858, when Wallace was ill with a fever in Ternate, in the Moluccas. Lying in bed all day, thinking about the species problem, he recalled the work of Thomas Malthus. Wondering why some individuals in each generation survive, while most die, he realized that this was not due to chance; those that lived and reproduced in their turn must be the ones best suited to the environmental conditions prevailing at the time. The ones that were most resistant to disease survived any illness they experienced; the fastest escaped predators; and so on. ‘Then it suddenly flashed upon me that this self-acting process would necessarily improve the race, because in every generation the inferior would inevitably be killed off and the superior would remain – that is, the fittest would survive.’²²

This is the nub of the theory of evolution by natural selection. First, offspring resemble their parents, but in each generation there are slight differences between individuals. Only the individuals best suited to the environment survive to reproduce, so the slight differences which make them successful are selectively passed on to the next generation and become the norm. When conditions change, or when species colonize new territory (as Darwin saw with the birds of the Galapagos Islands and Wallace saw in the Malay Archipelago), species change to match the new conditions and new species arise as a result. What neither Darwin nor Wallace knew, and which would not become clear until well into the twentieth century, was how heritability occurred or where the variations came from (see Chapter 14). But, given the observed fact of heritability with small variations, natural selection explained how, given enough time, evolution could produce an antelope adapted to a grazing lifestyle, the grass itself, a lion adapted to eat antelope, a bird that depends on a certain kind of seed for its food, or any other species on Earth today, including humankind, from a single, simple common ancestor.

It was the insight experienced on his sickbed in February 1858 that led Wallace to write a paper, ‘On the Tendency of Varieties to Depart Indefinitely from the Original Type’, which he sent to Darwin with a covering letter asking his opinion of the contents. The package arrived at Down House on 18 June 1858. The shock to Darwin at seeing his ideas pre-empted, as Lyell and others had warned might happen, came almost simultaneously with another, more personal, one – just ten days later, his infant son Charles Waring Darwin died of scarlet fever. In spite of his family problems, Darwin immediately tried to do the decent thing by Wallace, sending the paper on to Lyell with the comment:

Your words have come true with a vengeance – that I should be forestalled…I never saw a more striking coincidence; if Wallace had my MS sketch written out in 1842, he could not have made a better short abstract!…I shall, of course, at once write and offer to send it to any journal.²³

But Lyell, in conjunction with the naturalist Joseph Hooker (1817–1911), another member of Darwin’s inner circle, found an alternative plan. They took the matter out of the hands of Darwin (who was happy to leave them to it while he came to terms with the loss of little Charles, consoled Emma and made the funeral arrangements) and came up with the idea of adding Darwin’s 1844 outline of his theory to Wallace’s paper and offering it to the Linnean Society as a joint publication. The paper was read to the Society on 1 July, without causing any great stir at the time,²⁴ and duly published under the impressive title ‘On the tendency of species to form varieties; and on the perpetuation of varieties and species by natural means of selection by Charles Darwin Esq., FRS, FLS, & FGS and Alfred Wallace Esq., communicated by Sir Charles Lyell, FRS, FLS, and J. D. Hooker Esq., MD, VPRS, FLS, &c.’ That ‘&c.’ is irresistible!

You might have expected Wallace to be more than a little upset at this cavalier treatment of his paper without him even being consulted, but in fact he was delighted, and always afterwards referred to the theory of natural selection as Darwinism, even writing a book under that title. Much later, he wrote, ‘the one great result which I claim for my paper of 1858 is that it compelled Darwin to write and publish his Origin of Species without further delay’.²⁵ That he did; On the Origin of Species by Means of Natural Selection, or the Preservation of favoured races in the struggle for life was published by John Murray on 24 November 1859 and certainly did make a big impression, both on the scientific community and the world at large. Darwin went on to write other important books, accumulate more wealth and enjoy old age surrounded by his family in Down House, where he died on 19 April 1882; by and large, though, he kept out of the public debate about evolution and natural selection. Wallace also wrote more books, prospered in a more modest way for a time, but became an enthusiast for spiritualism, which tainted his scientific reputation. His spiritualist views also coloured his ideas about human beings, which he saw as specially touched by God, and not subject to the same evolutionary laws as other species. At the age of 43, in 1866 he married Annie Mitten, then just 18 years old, and the couple had a daughter and a son. But they were beset by financial worries, which only eased in 1880, when as a result of a petition which was primarily the idea of Darwin and Thomas Henry Huxley,²⁶ and was signed by several prominent scientists, Queen Victoria granted Wallace a pension of £200 a year for life. He was elected a Fellow of the Royal Society in 1893, received the Order of Merit in 1910 and died at Broadstone, in Dorset, on 7 November 1913. Charles Darwin was the first scientist we have encountered in these pages who was born after 1800; Alfred Wallace was the first who died after 1900. In spite of all the other achievements of science in the nineteenth century, their achievement reigns supreme.

^1.When enemy ships or booty were captured they were purchased by the Crown (or sold on the open market) and the proceeds shared among the men involved in the action in accordance with strictly laid down rules (most for the Admiral, of course, and least for the men); this was the prime motive that persuaded men to serve in the Royal Navy in spite of the extreme hardships and poor pay. Most men never received significant prize money, if any at all, but were sustained by the example of the few that hit the jackpot.

^2.Leaving the Scottish property in the hands of agents.

^3.Exactly the kind of country parsons you find in the pages of Jane Austen’s novels – she died in 1817, the year that Lyell became interested in geology.

^4.Quotes from Principles of Geology, Lyell’s italics.

^5.The subtitle on the title page of the volume reads, ‘Being an attempt to explain the former changes of the Earth’s surface, by reference to causes now in operation’. No scope there for any doubt in the mind of a prospective purchaser as to Lyell’s intentions!

^6.Although it certainly was; the nearest analogy, both with the drama of the science and the level of popular interest in the subject, is with cosmology in the late twentieth century.

^7.For evidence in support of these startling claims, see the biography of Erasmus Darwin by Desmond King-Hele. Coleridge visited Erasmus in 1796.

^8.By an ‘age’ Erasmus Darwin probably means about a hundred years, so his ideas on the timescale of evolution were way ahead of his time.

^9.At this time, remember, the Church still taught that species were created individually by God, and once created were fixed and immutable.

^10.Translation quoted by Jordanova.

^11.Quoted by Henry Osborn’s, From the Greeks to Darwin.

^12.Possibly the long walks were the cause of the developing interest in natural history, rather than resulting from it; this would fit in with the idea that Darwin really was deeply affected by the events of 1817 and 1818.

^13.The edition edited by Nora Barlow is the best source for such insights into Darwin’s early life.

^14.Quoted by Browne.

^15.Letter cited by Jonathan Howard, Darwin.

^16.In full, Journal of Researches into the Geology and Natural History of the Various Countries Visited by HMS ‘Beagle,’ under the Command of Captain FitzRoy, R.N., from 1832 to 1836.

^17.The essay can still be found in print in an edition edited by Antony Flew.

^18.The flaw in this argument can be summed up in one word, almost taboo in Victorian times – contraception.

^19.Howard Gruber, Darwin on Man.

^20.My Life.

^21.Delayed by the outbreak of the Crimean War.

^22.My Life. This was written long after the event, which explains Wallace’s use of the term ‘survival of the fittest’, which did not occur in the original formulations of the theory by Darwin or by himself.

^23.See the Autobiography, edited by Francis Darwin.

^24.In his autobiography, Darwin commented that ‘our joint productions excited very little attention, and the only published notice of them which I can remember was by Professor Haughton of Dublin, whose verdict was that all that was new in them was false, and what was true was old’.

^25.Quoted by Wilma George.

^26.Huxley (1825–1895) deserves far more space than we can give him here, not so much for his own scientific work, which was important but not groundbreaking, or even his role as ‘Darwin’s bulldog’ in promoting the theory of natural selection. His real importance in the history of science is that by dint of sheer ability and hard work he clawed his way up from humble origins to become a leading scientific figure, fought for better education for the working classes and was instrumental in seeing new seats of learning, with entry not restricted to gentlemen, opened up in London, Birmingham and Manchester, as well as Johns Hopkins University in Baltimore. He helped to establish science as a profession that people were paid to do, rather than a hobby indulged in by the rich. It is one of life’s little ironies that in 1858 he effectively championed the cause of the gentleman amateur Darwin (who stood for everything Huxley hated, except that he was a brilliant scientist) and not the working-class Wallace. Our only consolation for relegating Huxley to a footnote is that you can find out all about him in Adrian Desmond’s superb biography.