Science of Discworld III

that version of Roundworld’s historical record, and the wizards are exercising extreme care and attention in the hope of steering history through, past, and around these causal singularities.
    For example, the Beagle really did come under fire from a cannon. When the ship tried to enter the harbour at Buenos Aires in 1832, one of the local guard ships fired at it. Darwin was convinced that he heard a cannonball whistle over his head, but it turned out that the shot was a blank, intended as a warning. FitzRoy, mutteringangrily about insults to the British flag, sailed on, but was stopped by a quarantine boat: the harbour authorities were worried about cholera. Incensed, FitzRoy loaded all of the cannons on one side of his ship. As he sailed back out of the harbour he aimed them all at the guard ship, informing its crew that if they ever fired at the Beagle again, he would send their ‘rotten hulk’ to the seabed.
    Darwin really did learn to throw a bolas, too, on the pampas of Patagonia. He enjoyed hunting rheas, and watching the gauchos bring them down by entangling a bolas in their legs. But when he tried to do the same, all he managed was to trip up his own horse. The Origin might have vanished from history’s timeline then and there, but Darwin survived, with only his pride hurt. The gauchos found the whole thing hugely amusing.
    Charles even took part in suppressing an insurrection. When the Beagle reached Montevideo, shortly after the cannonball incident, FitzRoy complained to the local representative of Her Majesty’s Royal Navy, who promptly set sail for Buenos Aires in his frigate HMS Druid to secure an apology. No sooner had the warship disappeared from view than there was a rebellion, with black soldiers taking over the town’s central fort. The chief of police asked FitzRoy for help, and he dispatched a squad of fifty sailors, armed to the teeth … with Darwin happily bringing up the rear. The mutineers immediately surrendered, and Darwin expressed disappointment that not a shot had been fired.
    No expense, then, has been spared to bring you historical truth, inasmuch as so weighty a characteristic as truth can be attributed to something as ethereal as history. Except for the giant squid, of course. That happened in a different timeline, when the malign forces were getting extremely desperate and strayed into Twenty Thousand Leagues Under the Sea through some obscure warp in L-space.
    The most important similarity between the two Darwins is less exciting, but essential to our tale. The real Charles Darwin, like his fictional counterpart, began by writing the wrong book . In fact, hewrote eight wrong books. They were very nice books, very worthy … of great scientific value … and they did his reputation no harm at all … but they weren’t about natural selection, his term for what later scientists would call ‘evolution’. Still, that book was brewing merrily away in the back of his mind, and until he was ready to bring it off the back burner, he had plenty of other things to write about.
    It had been FitzRoy who had put the idea of authorship into his head. The Beagle ’s captain had signed himself up to write the story of his round-the-world voyage, based on the ship’s log. He had also agreed to edit an accompanying book about a previous survey by the same vessel – the one where Stokes had shot himself. As the Beagle headed north-west from Cape town, stopped briefly at Bahía in Brazil, and turned north-east across the Atlantic towards its final destination in Falmouth, FitzRoy suggested to Darwin that the latter’s diary might form the basis of a third volume on the natural history of the voyage, completing the trilogy.
    Darwin was nervous but excited at the prospect of becoming an author. He had another book in mind, too, on geology. He’d been thinking about it ever since his revelation on the island of St Jago.
    As soon as the ship had returned to England, FitzRoy got married and went on honeymoon, but he also made an impressive start to his book. Darwin began to worry that his own slow writing would delay the whole project, but FitzRoy’s early enthusiasm soon ground to a halt. Between January and September 1837 Charles worked flat out, overtook the captain, and towards the year’s end he sent his finished manuscript to the printer’s. It took FitzRoy more than a year to catch up, so Darwin’s contribution was held back, finally seeing the light of day in 1839 as volume 3 of