[1] . Literally, 'jointed acorn'

He became ill, but continued working on barnacles. In 1851 he published two books about them - one on fossil barnacles for the Palaeontographical Society, the other on the living ones for the Royal Society. By 1854 he had produced a sequel to each of them.

These were Darwin's eight wrong books:

1839 Journal of Researches into the Geology and Natural History of the Various Countries Visited by H.M.S. Beagle

1842 The Structure and Distribution of Coral Reefs

1844 Geological Observations on the Volcanic Islands Visited During the Voyage of H.M.S. Beagle

1846 Geological Observations of South America

1851 A Monograph on the Fossil Lepadidae, or, Pedunculated Cirripedes of Great Britain

1851 A Monograph on the Sub-class Cirripedia volume 1

1854 A Monograph on the Fossil Balanidae and Verrucidae of Great Britain

1854 A Monograph on the Sub-class Cirripedia volume 2

Not a hint of transmutation of species, the struggle for life, or natural selection.

Yet, in a strange way, all of his books - even the geological ones - were crucial steps towards the work that was now putting itself together inside his head. Darwin's ninth book would be pure dynamite. He wanted desperately to write it, but he had already decided that it would be far too dangerous to be published.

It is a common dilemma in science: whether to publish and be damned, or not to publish and be pre-erupted. You can have the credit for a truly revolutionary idea, or a quiet life, but not both.

Darwin was wary of publicity, and he was scared that putting his views into print might damage the Church. But there is nothing that more effectively galvanises a scientist than the fear that somebody else will pip them to the winning post. In this case, that somebody was Alfred Russel Wallace.

Wallace was another Victorian explorer, equally keen on natural history. Mostly because he could sell it. Unlike Darwin, he was not `gentry', and had no independent income. He was the son of an impecunious lawyer [1] and had been taken on at age fourteen as a builder's apprentice. He spent his evenings drinking free coffee in the Hall of Science off Tottenham Court Road in London. This was a socialist organisation, dedicated to the overthrow of private property and the downfall of the Church. Wallace's experiences as a youth reinforced a left-wing view of politics. He financed his own travels, and made a living by selling the specimens he collected - butterflies, beetles (a thousand labelled specimens per box, the dealers demanded), [2] even bird skins. He went on a collecting expedition to the Amazon in 1848, and again to the Malay Archipelago in 1854. There, in Borneo, he sought orang-utans. The idea that humans were somehow related to the great apes was simmering away in the collective subconscious, and Wallace wanted to investigate a potential human ancestor. [3]

One miserable Borneo day, when a tropical monsoon raged outside and Wallace was stuck indoors, he put together a little scientific paper outlining some modest ideas that had just popped into his head. It eventually appeared in the Annals and Magazine of Natural History, a rather ordinary publication, and it was about the 'introduction' of species. Lyell, aware of Darwin's secret interest in such matters, pointed the paper out to him, and Charles began to read it. Then another of Charles's regular correspondents, Edward Blyth,

[1] Yes, we know it sounds unlikely, but apparently there are such things.

[2] It was a good job that God had such a fondness for beetles.

[3] Its potential for Librarianship was not widely recognised at that time.

wrote from Calcutta with the same recommendation. `What do you think of Wallace's paper in the Ann M.N.H.? Good! Upon the whole!' Darwin had met Wallace shortly before one of the latter's expeditions - he couldn't remember which - and he could see that the Ann M.N.H. paper had useful things to say about relationships between similar species. Especially the role of geography. But apart from that, he felt that the paper contained nothing new, and made an entry to that effect in one of his notebooks. Anyway, it seemed to Darwin that Wallace was talking about creation, not evolution. Nevertheless, he wrote to Wallace, encouraging him to continue developing his theory.

This was a Really Bad Idea.

Encouraged by Lyell and others, who were now warning him that if he delayed too long, others might snatch the prize, Darwin was putting together ever more elaborate essays on natural selection, but he continued to dither about publication. All that changed in an instant in June 1858, when the postman dropped a bombshell through Charles's letterbox. It was a package from Wallace, containing a twenty-page letter, sent from the Moluccas. Wallace had taken Darwin's advice to heart. And he had come up with a very similar theory. Very similar indeed.

Calamity. Darwin declared that his life's work was `smashed'. `Your words have come true with a vengeance,' he wrote to Lyell. The more he read Wallace's notes, the closer the ideas seemed to his own. `If Wallace had my MS manuscript sketch written out in 1842, he could not have made a better short abstract!' Darwin moaned in a letter to Lyell.

Staid Victorians would soon consider both Wallace and Darwin to be out of their minds, and Wallace certainly came close, for he was suffering from malaria when he composed his letter to Darwin. As a good socialist, Wallace had been taught not to trust the reasoning of Malthus, who had argued that the world's ability to feed itself grew linearly, while the population grew exponentially - implying that eventually the population would win and there would be too little food to go round. Socialists believed that human ingenuity could postpone such an event indefinitely. But by the 1850s even socialists were beginning to view Malthus in a more favourable light; after all, the threat of overpopulation was a very good reason to promote contraception, which made excellent sense to every good socialist. Half-delirious with fever, Wallace thought about the rich variety of species he had encountered, wondered how that fitted in with Malthus, put two and two together, and realised that you could have selective breeding without the need for a breeder.

As it turned out, he didn't have quite the same view as Darwin. Wallace thought that the main selective pressure came from the struggle to survive in a hostile environment - drought, storm, flood, whatever. It was this struggle that removed unfit creatures from the breeding pool. Darwin had a rather blunter view of the selection mechanism: competition among the organisms themselves. It wasn't quite `Nature red in tooth and claw' as Tennyson had written in his In Memoriam of 1850, but the claws were unsheathed and there was a certain pinkness to the teeth. To Darwin, the environment set a background of limited resources, but it was the creatures themselves that selected each other for the chop when they competed for those resources. Wallace's political leanings made him detect a purpose in natural selection: to `realise the ideal of a perfect man'. Darwin refused even to contemplate this kind of utopian hogwash.

Wallace hadn't mentioned publishing his theory, but Darwin now felt obliged to recommend it to him. At that point it looked as if Charles had compounded his Really Bad idea, but for once the universe was kind. Lyell, searching for a compromise, suggested that the two men might agree to publish their discoveries simultaneously. Darwin was concerned that this might make it look as if he'd pinched Wallace's theory, worried himself to distraction, and finally handed the negotiating over to Lyell and Hooker and washed his hands of it.

Fortunately, Wallace was a true gentleman (the accident of breeding notwithstanding) and he agreed that it would be unfair to Darwin to do anything else. He hadn't realised that Darwin had been working on exactly the same theory for many years, and he had no wish to steal such an eminent scientist's thunder, perish the very thought. Darwin quickly put together a short version of his own work, and Hooker and Lyell got the two papers inserted into the schedule of the Linnaean Society, a relatively new association for natural history. The Society was about to shut up shop for the summer, but the council fitted in an extra meeting at the last minute, and the two papers were duly read to an audience of about thirty fellows.