Darwin's Voyage of the Beagle
An introduction by Gordon Chancellor
Darwin's Journal of researches better known as the Voyage of the Beagle was his 'first literary child'. It was the published version of his Beagle diary, kept from embarkation as naturalist on HMS Beagle at Devonport in October 1831 up to the end of his voyage around the world at Falmouth in October 1836 (1).
The Beagle diary was initially written for Darwin's family back in Shrewsbury, perhaps especially for his father who – like Robinson Crusoe's fictitious father - had initially dismissed the offer to his son of participating in a long sea voyage as a 'wild scheme'. Darwin, as a student, had adored Alexander von Humboldt's Personal narrative and longed to be a scientific explorer, but he must also have felt a heavy weight of responsibility towards his father as the little Beagle finally departed England at the end of 1831.
Although he was at liberty to leave the voyage at any point, Darwin's Beagle diary reveals his determination not to squander any opportunity and to withstand its hardships throughout five long years. When at sea he often suffered the misery of sea sickness and in the final year of the voyage homesickness must have been almost as unbearable. He was also in serious danger on many occasions, but he never gave up and he returned with a rich harvest of specimens and new ideas (2). We know from his Autobiography how excited he was, on the homeward leg in 1836, by a letter from his sister Susan telling him that Professor Adam Sedgwick had told Darwin's father that once back in England he would 'have a great name among the naturalists of Europe'.
Half a year after his return to England, in the Spring of 1837, Darwin at Captain FitzRoy's suggestion (see Darwin to Caroline Darwin, 29 April 1836) started adapting his Beagle diary for publication as part of the official 'Narrative' of the voyage. Darwin deleted many of his personal reflections and most of the account of the two-thirds of the voyage spent at anchor or sailing back and forth between survey locations. (See the complete itinerary of Darwin's voyage by Kees Rookmaaker here.) In their place he imported a great deal of material from his scientific diaries from the voyage (the Geological diary and the Zoological diary), compiled from the fifteen field notebooks he had carried on the third of the voyage he spent exploring on land. He had read many 'personal narratives' by this time, such as the highly-praised travel journals from Chile, Peru and Mexico of Captain Basil Hall (1824: Volume 1 Text Volume 2 Text) so he had excellent models to follow.
Whereas the Beagle diary was of course written chronologically, forming a very readable account of what Darwin saw and did, he re-arranged the published version into geographical order to clarify his narrative. This re-arrangement had the great advantage of conveying a much stronger sense of Darwin's voyage of progression, both as a five-year circumnavigation and as a journey of self-discovery. Darwin was 'inventing' himself through his re-writing as a man who had undergone a sea-change, from an 'extraordinarily well-trained natural scientist' (Thomson 1995) into a sophisticated and knowledgeable travel writer in the Romantic tradition (Richards and Ruse 2016). Darwin was, in short, transforming himself from a man inspired by Humboldt into a man who would himself inspire the next generation of travellers.
Darwin's re-writing was completed in June 1837 and in print by early 1838, but delays with the other volumes meant that they could not be published by Henry Colburn until June 1839 as Journal and remarks. The delay did at least give Darwin the opportunity to add a lengthy appendix bringing his research up to date. His volume seems to have been in greater demand than the others, which had been written or edited by Captain FitzRoy, and by August was re-issued as the standalone 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 1832-1836. This was warmly received by the critics and by the 'great guns' of the scientific community, notably Humboldt but also Charles Lyell, who had been Darwin's geological inspiration on the voyage and was now his closest colleague. The Journal of researches, together with the five-volume Zoology of the Beagle (1838-1843, edited by Darwin) and the three-volume Geology of the Beagle (1842-1846) and a multitude of shorter papers all available here, comprise Darwin's publications from the voyage, although he continued to use his findings throughout his career, most notably in The origin of species (1859).
The success of the Journal encouraged John Murray to offer Darwin the chance to publish a second edition. Before attending to that, however, Darwin wanted to spend some time on a project he had been working on privately since the end of the voyage. Once the lion's share of his Beagle publications was either published or in press, in 1844 he drafted a substantial Essay summarizing his theory of evolution on which he had been amassing notes since early 1837. Once he had finished it and explained to his wife Emma in July 1844 that he wanted her to get it published if he died prematurely, he then 'parked' the Essay, as he knew it would need a lot more work before his theory would be ready for the public. He returned to preparing his Geological observations on South America which was completed in April 1845.
Darwin then worked on the second edition of the Journal, which eventually appeared in August 1845 in John Murray's popular 'Home and Colonial Library'. This is the book known since 1905 as The voyage of the Beagle which we refer to here as the Journal of researches. Nora Barlow estimated that around 11,000 words were cut from the first edition to the second and the number of chapters was reduced from twenty-three to twenty-one. Word counts of the two editions on Darwin Online indicate that the reduction is closer to 26,000.
This was achieved by the merging of material from chapters 9-12 into chapters 8-10, so that chapters 13-23 became chapters 11-21. Darwin condensed much from the earlier edition but added a fulsome dedication to Lyell and a considerable amount of new material based on his more recent research, including the new identifications of many of his Beagle specimens. Importantly, Darwin also expanded the sections about the indigenous Fuegians (as the peoples of Tierra del Fuego were called) – material he had left out in the first edition because FitzRoy had covered it in his volume. Knowing today that Darwin had already written out a summary of his theory of evolution in the Essay of 1844 and that within fifteen years he would publish the Origin, it is possible now to read his maturing theory's influence on the 1845 edition of Journal of researches.
Many of Darwin's various transactions relating to the publication of the new edition are detailed in The Correspondence of Charles Darwin, vol. 4. These include his correspondence with Joseph Hooker regarding the Beagle plants and his response to critiques, such as Humboldt's enthusiastic comments in Kosmos (1845-), a book which Darwin found rather disappointing. The Journal of researches was marketed as 'cheap literature for all classes' and was a step down in printing quality, with the two fine maps from the first edition omitted, although several important woodcuts were added, mostly from Coral reefs and Volcanic islands. Nevertheless, it was quickly established as an outstanding piece of travel writing with the order of geology and natural history reversed in the title, perhaps reflecting Darwin's shift of interest since 1839. Murray must have been pleased that he had shrewdly secured the copyright from Darwin for £150.
The Journal of researches has been continuously in print since 1845 and is second only to the Origin as Darwin's most widely read book. An American edition came out in 1846 and a higher quality edition by Murray appeared in 1860 in the same green cloth binding as that used for the Origin. The title on the spine of this and all subsequent Murray editions was A naturalist's voyage around the world. A postscript to the June 1845 preface was appended to the 1860 edition, updating a few details, but this is omitted in later Murray editions where the amendments are added as footnotes on the relevant pages.
A fine illustrated edition was brought out in 1890 which included a plate showing two important diagrams of the Beagle based on drawings by Philip Gidley King, who had been a midshipman on Darwin's voyage. Murray attached his own preface to this edition in which he says that "The extraordinary minuteness and accuracy of Mr. Darwin's observations, combined with the charm and simplicity of his descriptions, have ensured the popularity of this book with all classes of readers and that popularity has even increased in recent years." A cheaper illustrated edition by Murray came out in 1901, with a painting of the ship by First Lieutenant John Wickham. Unfortunately, the original of this painting seems not to have survived.
The full title 'The voyage of the Beagle' was first used in 1905 and this has ever since been the title by which the book is known. R. B. Freeman, the great bibliographer of Darwin's writings, recorded that the book had been translated into 22 languages by 1977. Continuing his work, the Darwin Online project has identified 32 languages in the Freeman Bibliographical Database. Darwin Online currently provides Journal of researches in Chinese, Croatian, Danish, Dutch, Finnish, French, German, Greek, Italian, Japanese, Polish, Portuguese, Romanian, Russian, Spanish and Swedish. This makes the Journal of researches Darwin's second most widely translated work after Origin. Freeman found that Origin had been translated into 29 languages. The Darwin Online project has so far recorded a total of 56 languages—a record for any scientific book.
The Journal of researches and the Origin are in many ways closely connected in that both have their genesis in the Beagle voyage and reflect their author's great powers of seeing and explaining nature's meaning. Of all Darwin's literary progeny, however, they are in other ways very unlike. The Journal of researches is one of the most charming travel books and in its day inspired many fine naturalists like Wallace and Bates to emulate Darwin's model. The Origin, on the other hand, took its nineteenth-century readers much, much further, on an intellectual voyage into regions many of them trembled to enter. It is a masterpiece of rhetoric and undoubtedly one of the most important books ever written.
This introduction is intended to guide readers through the Journal of researches and to tease out some of the themes which Darwin dealt with, especially those which we can now read as having an evolutionary importance. This is complementary to the approach taken by Howard Gruber in his excellent paper (1994) although he focused on the changes made between the two editions of Journal of researches and arranged these thematically. We take a chronological approach, starting in June 1832, considering passages from the Journal of researches which link back to jottings from the field notebooks so that it becomes possible to guess how Darwin's thinking about species developed through the voyage. It is important not to 'read back' into the notebooks what Darwin believed in 1845, as he did not clearly doubt the fixity of species until almost the end of the voyage and was not convinced of transmutation until the spring of 1837 (Hodge 2010). Of course, there is no substitute for reading the whole Journal of researches itself, but we hope that by highlighting this selection readers' we be better able to understand this historic work.
SPIDERS, BEETLES AND ANTS: NATURE'S ECONOMY
In June 1832, while Darwin was exploring the tropical environs of Rio de Janeiro, he jotted the following remarkable observation in his Cape de Verds notebook: "Scale in nature amongst spiders kept up by hymenopt [i.e. hymenoptera - ants] in absence of Carabid [i.e. Caribidae – ground beetles] supplied by ants – may after been less of insects & caterpillars" (p. 84b)
What Darwin is saying is that he believes that unlike in Britain, where he had been collecting beetles so enthusiastically as a student, in Rio the carabid beetles are not among the top predators of the insect world. Whilst in Rio he was able easily to catch numerous species of spiders and smaller beetles, but the more 'rapacious' beetles were much harder to find. He was surmising that in the tropics the carabids' place in Nature's scale – today we would call it their 'ecological niche' – is occupied by spiders and carnivorous ants, the latter of which are insects of the hymenopteran order.
Perhaps Darwin in this jotting is also suggesting that ants might be driving down the numbers of caterpillars and therefore of butterflies and moths. If this is the case, this may be the earliest example of Darwin considering the struggle for life, a key element of his theory of natural selection which he arrived at in 1838. This simple note shows how acute, even at this early stage in the Beagle voyage, were Darwin's powers of drawing profound inferences from his fieldwork. It also proves emphatically how well his youthful natural history pursuits had prepared him for the opportunities opening up to him (Smith 1987).
The following is from Darwin's Journal of researches account of his Rio invertebrate collecting. Here he extends his ecological ruminations to ask why there are in the tropics so few carabids and yet so many large carnivorous mammals (quadrupeds), such as lions and jaguars, and adds a delightful footnote: "I may mention, as a common instance of one day's (June 23rd) collecting, when I was not attending particularly to the Coleoptera, that I caught sixty-eight species of that order. Among these, there were only two of the Carabidæ, four Brachelytra, fifteen Rhyncophora, and fourteen of the Chrysomelidæ. Thirty-seven species of Arachnidæ, which I brought home, will be sufficient to prove that I was not paying overmuch attention to the generally favoured order of Coleoptera." (p. 34)
INDIGENOUS PEOPLES
In the Journal of researches Darwin describes his first encounter with the indigenous people of Tierra del Fuego. This took place on 17 December 1832, on pp. 204-205.
About a month later and just a week after the Beagle nearly sank in a terrible storm on 13 January 1833 (3), Darwin set out with an expedition to chart the Beagle Channel. Captain FitzRoy was also hoping to re-establish contact with Jemmy Button's people whom he knew from the Beagle's previous voyage. Jemmy, who was said to have been bought for one button and whose Yahgan name was Orundellico, was one of the three surviving Fuegian Indians whom FitzRoy had taken back to England and now wanted to resettle with their families (see van Helvert & van Wyhe 2021, p. 40). FitzRoy wanted Jemmy to help to make a base for Richard Matthews, sent by The Church Missionary Society to spread Christianity among the Indians. On the expedition, in his Buenos Ayres notebook Darwin concentrated on recording the geology, but around the 19th they entered the area inhabited by the indigenous people and he made the following entries:
…long pull in boat.— scenery same, astonishment & following of savages wild appearance on hill: naked long hair: (give them many things. slings dinner time) attempt to drive them away by fires, innocent naked most miserable very wet…… wet night yet comfortable at starting afraid of fighting with savages women & children retreated signs of great fire [on] side of hill. (pp. 20a-21a)
This was the basis for an important passage from the Journal of researches which shows how quickly situations could turn from tranquil to tense. (pp. 218-219)
In the event the prospective 'mission' was set up on the 23 January at Woollya on the southwest coast of Navarin Island. This is about 10km south of what is now Ushuaia, the two places separated by the Beagle Channel and the Argentine/Chile border (4). The whole exercise was, however, a disaster and Matthews had to be rescued from constant harassment on 6 February otherwise he would probably have been killed. Darwin made several more notes during that fortnight in the Buenos Ayres notebook (pp. 30a-51a) which convey the futility of the project. Matthews eventually left the Beagle to join his brother in New Zealand, nevertheless the episode left a deep impression on Darwin.
TUCO-TUCOS: 'USE AND DISUSE' AND LAMARCK
In the second week of August of 1833 Darwin was engaged in a risky ride from El Carmen on the Rio Negro north to Bahia Blanca, where he intended to meet the Beagle. He was always in the company of Gauchos and under the protection of General Rosas whose soldiers were doing their best to exterminate the native people. The Beagle having not arrived, Darwin explored the country around the Rio Colorado until he finally embarked at the end of August. He was full of traveller's tales and eager to continue his 1,000km ride to Buenos Aires, but first he spent several days excavating important fossil mammal bones to send back to England (Allmon 2015). Most of his observations from this expedition are recorded in his Falkland notebook. Eventually he obtained his permits and horses and set off overland, arriving on 20 September 1833.
Around the 9th and 10th August Darwin made notes about the tuco-tuco (5), a rodent named after its characteristic 'tuc-tuc' call. He describes the animal and its relatives as follows:
Toco Toco or Taupes (6) & Aperea (7) different from Maldonado, latter smaller tamer, appears more in day feeders frequent hedges & holes: have 2 young at a time latter quite different more more distinct louder sonorous, like distant cutting of small tree more peculiar noise double & not three or 4 times repeated only twice, said to have no tail (?) & blind (?) Inhabits same sites — more injurious than Talpe (pp. 106a-107a)
Darwin did not mention the Rio Negro tuco-tuco in his personal Beagle diary but he added some notes to those he had already made about a very similar animal at Maldonado in May 1833 in his Zoology diary (Keynes 2000, pp. 165-166). By the time he wrote up his Animal Notes, DAR29.1.5-8v, in mid-1836, he had confirmed that the Rio Negro species was separate from the Maldonado species. In the notes to his transcription of the Notes, Richard Keynes indicates that the species described in the Falkland notebook is Kerodon kingii, see Mammalia, pp. 88-9, whereas the tuco-tuco is Ctenomys brasiliensis, Mammalia, pp. 79-82. Nevertheless, the two species had many similarities, including the fact that they lived in burrows and suffered from inflammation of the nictating membrane of their eyes, often leading to blindness, hence the note 'said to have no tail (?) & blind (?)'.
The significance of all this is that Darwin was struck by the fact of an animal possessing eyes, when much of the time these delicate organs were of no use to the animal and were in fact so damaged that the animal often went blind. Why would any animal created for living in burrows have such an imperfect organ? As he wrote in his Animal Notes:
Considering the subterranean habits of the tuco-tuco, the blindness, though so frequent, cannot be a very serious evil. Yet it appears odd that an animal should possess an organ constantly subject to injury. The mole, whose habits are so similar in every respect, excepting in the kind of food, has an extremely small protected eye, which although possessing a limited vision, seems at once adapted to its manner of life. (p. 8v)
Darwin repeated these observations in the Journal of researches, but added a rather sarcastic reference to Lamarck's evolutionary theories (8):
Considering the strictly subterranean habits of the tucutuco, the blindness, though so common, cannot be a very serious evil; yet it appears strange that any animal should possess an organ frequently subject to be injured. Lamarck would have been delighted with this fact, had he known it, when speculating* (probably with more truth than usual with him) on the gradually-acquired blindness of the Aspalax, a Gnawer living under ground, and of the Proteus (9), a reptile living in dark caverns filled with water; in both of which animals the eye is in an almost rudimentary state, and is covered by a tendinous membrane and skin… In the tucutuco, which I believe never comes to the surface of the ground, the eye is rather larger, but often rendered blind and useless, though without apparently causing any inconvenience to the animal: no doubt Lamarck would have said that the tucutuco is now passing into the state of the Aspalax and Proteus. Philosophie Zoologique, v. 1, p. 242 (pp. 51-52)
The tuco-tuco eventually became a cornerstone of Darwin's discussion of 'use and disuse' in the Origin, p. 137. By 1859 he took it as read that the tuco-tuco had eyes because it had inherited them from some surface-dwelling ancestor and he suggested that natural selection would eventually result in some protection for the animals' eyes. It is clear from the Animal Notes that the case had already started him thinking some time before the end of the Beagle voyage, but we can only speculate as to how much this contributed to his growing doubts about the special creation of perfectly adapted organisms.
DARWIN'S RHEA: NOT THE COMMON OSTRICH
On the Rio Negro expedition in August 1833, Darwin made the following jotting in his Falkland notebook:
…ostriches. males certainly sit on eggs easily distinguished: stray eggs first laid: many females, said, I know not on what evidence to lay in one nest. about 50 eggs in the belly: analogy to African method manner of laying: — Avestruss Petises: colour oveiro (p. 131a)
Darwin is here referring to the 'Avestruz petise' which is the small rhea of Patagonia, ('petiso' being a slang word used in Argentina for a very short person); it is listed as Rhea Darwinii in Birds (pp. 123-5, plate 47) and its current name is Pterocnemia pennata. See Zoology notes (pp. 101-102,188-9) and Ornithological notes, (pp. 268-277). It is not clear what Darwin means here by 'oveiro' although it is presumably a reference to the bird's eggs.
On the next stage of his expedition, on the Bahia Blanca to Buenos Ayres leg, Darwin made some further notes on this bird, on Saturday 7 September, in his B. Blanca notebook:
Avitruce Petisses frequent sea side. South of Colorado overo. feathers same structure body & neck & head similar legs rather shorter, covered with feathers to claws. has sort of fleshy 4th toe without claw. — eggs a trifle smaller: Head with scattered hairs. cannot fly. — good information. — my prospects are now better, gracias a dios start in the morning — hazy air (pp. 28a-29a)
Finally, the following year, on the Rio Santa Cruz, around 24 April 1834, he noted in his Banda Oriental notebook: "Saw an ostrich about ⅔ size of common & much darker coloured exceedingly active & wild" (p. 52)
We know from Darwin's Red Notebook that the way the smaller rhea replaces the 'common sort' as the traveller goes south was important evidence nudging him towards a transmutation position in early 1837 (see Herbert 1980 for full discussion). In the Journal of researches, however, he chooses not to discuss this but instead to turn his forgetfulness of April 1834 to amusing advantage. (p. 92)
Perhaps Darwin recalled sitting by the camp fire twenty-five years previously, when in theOriginthe rhea was pressed into service as another exhibit in his case for evolution: (Origin, p. 349).
TURCOS AND TAPACOLOS, CHEUCAUS AND GUID-GUIDS: THEY INHABIT DIFFERENT HABITATS SO WHY ARE THEY SO OBVIOUSLY RELATED?
While on the continent of South America Darwin recorded observations about the bird species he encountered, firstly and briefly in his field notebooks, then in his Zoological diary and finally – in June or July of 1836 – in his detailed Ornithological notes. Although he could use the extensive library on the Beagle and already had a good knowledge of birds and could often apply temporary European names for the species he found, sometimes he encountered little known or even unknown species.
There were some species which seemed difficult to fit into the picture of nature which Darwin had been brought up with in which species were assumed to have been specially created to suit the environments in which they are found. This 'creationist' view was exemplified by William Paley's Natural theology, a book Darwin had greatly admired at Cambridge, and championed by Charles Lyell in his Principles of geology, which was the most important influence on Darwin's thinking during the voyage.
We have discussed above Darwin's discovery that the smaller rhea replaced the larger species going south in Patagonia. We know from jottings made in early 1837 in his Red Notebook that the rheas contributed to his rejecting the 'creationist' view, because he had seen no obvious change of habitat as he travelled south which would explain the replacement. There is, however, no documentary evidence that Darwin saw anything challenging about his discovery during the voyage. We may now consider a handful of species, lumped under the name 'Myothera' in the Ornithological notes, which may have been more intriguing to Darwin as he encountered them about a year later, while preparing to leave the South American mainland. These species are now classed as members of the family Rhinocryptidae and are discussed by Herbert (1980), Hodge (2010) and Steinheimer (2004).
Darwin made few notes on the 'Myothera' species in his field notebooks (10) But in chapter 12 of the Journal of researches he described two species he encountered in central Chile (the 'Turco' and 'Tapaculo'), then in chapter 13 he described another two from further south in Chiloe and Chonos (the 'Cheucau' and 'Guid-guid'. Although lengthy, both descriptions are worth reading as they are charmingly anthropomorphic and show Darwin's deep natural sympathy for animal behaviour. (See Turco p. 270, Tapacolo pp. 271-272, Cheucau p. 288, Guid-guid pp. 288-289.)
It was probably while sorting the previously undescribed mockingbirds of the Galápagos collected the previous September and October and preparing his Ornithological notes, that Darwin realized there were several distinct varieties on different islands which prompted his famous note: "If there is the slightest foundation for these remarks the zoology of Archipelagoes will be well worth examining; for such facts [would inserted] undermine the stability of Species"(p. 262). By the time the 1845 edition of the Journal of researches was written the ornithologist John Gould had examined the birds collected by Darwin and others on the Beagle and published his descriptions in Birds, usually with notes on the birds' habits added by Darwin.
As Jon Hodge has argued persuasively in his important paper (2010), what makes the 'Myothera' so intriguing is that Darwin clearly saw their similarities, as they were species of the same genus. This may seem odd, in view of the significance to him that we attributed above to the differences he noticed between the Galápagos mockingbirds. The key point, however, is that the 'Myothera' species were encountered in various habitats spread down the length of Chile, whereas the Galápagos mockingbirds, which he assumed were only varieties of one species, all lived on similar islands and seemed, therefore, only to differ by virtue of being separated by stretches of sea. It may be significant that in the Ornithological notes Darwin's discussion of the 'Myothera' is only three or four manuscript pages before the discussion of the mockingbirds.
If Lyell's 'creationist' position was valid and species were perfectly adapted to their habitats, there would be no reason for the 'Myothera' species to be similar if inhabiting different habitats unless they shared a common ancestry. Of course, this is historical guess work as there is no 'smoking gun' in his notes or in the Journal of researches of Darwin's thoughts about the origins of the 'Myothera' species. There is, as we have seen, for the mockingbirds, where again common ancestry of what Darwin thought were varieties of a mainland species combined with isolation would be the best explanation for the differences which he had discovered. The enormous significance of the differences was only really clear in the spring of 1837 when Gould told Darwin that the mockingbirds were a group of new species, not just varieties.
Darwin's recognition, albeit perhaps subconscious, that it was common ancestry linking the various 'Myothera' species – and that adaptation was relative and not perfect — removed for him any logical objection to descent with modification. What he needed then was to find a possible cause for the modification, and this he suspected would be found in the isolation of variants which occurred when barriers were imposed, such as the sea between the islands of the Galápagos. Thus, Darwin's first tentative glimpses of descent with modification in living species was of a process which allowed change while retaining resemblances.
MR LYELL'S ADMIRABLE LAWS: THE ASSUMPTION OF IMMUTABILITY
By the end of 1834, at about two-thirds point of the voyage, Darwin had been in Chile for a year and had had many adventures, not least exploring Chiloe Island, making his first treks in the Andes and being seriously ill – probably with typhoid. Then during the southern summer, he saw great volcanoes erupt in January 1835 and experienced a huge earthquake in February. By 18 March he was ready to commence his epic traverse of the Andes from Santiago across to Mendoza and arriving back again, exhausted, on 10 April.
Just over half way through his extraordinary St Fe notebook, while descending the Portillo Pass into Argentina on 24 March 1835, Darwin made the following entry:
Vegetation spring bushes. many flowers like Patagonia: Blue & Orange finch long-tailed tit: tufted do. red-tail Furnarius. Guanaco dung in heap: just the same in appearance (Ulloa): very many mice: Biscatcha on a peak: very different aspect: more bushy tail. tinge of red in breast (p. 133a)
Darwin was here realising the differences between the plants and animals on the opposite sides of the Cordillera. Gradually he came to see these differences as highly significant. We see this in a passage in the Journal of researches on p. 326. In a footnote to this, which strikes us today as blatantly suggestive of his evolutionary perspective, Darwin referred to Lyell's interest in this link between geology and the distribution of species:
This is merely an illustration of the admirable laws, first laid down by Mr. Lyell, on the geographical distribution of animals, as influenced by geological changes. The whole reasoning, of course, is founded on the assumption of the immutability of species; otherwise the difference in the species in the two regions, might be considered as superinduced during a length of time. (pp. 326-327)
THAT MYSTERY OF MYSTERIES
Following his Andean expedition, after resting in Valparaiso, Darwin in late April 1835 commenced an immensely long geological ride northwards up the Chilean coastal range to Copiapò, arriving there on 22 June. After an exploration of the Despoblado valley he then sailed north on the Beagle to Iquique and Lima in Peru where he was based for six weeks, eventually sailing for the Galápagos on 7 September and so starting the final leg of the circumnavigation. He visited four of the Islands: Chatham, Charles, Albemarle and James (11).
Darwin's account of the Galápagos in chapter 17 of the Journal of researches should of course be read in its entirety as a classic description of one of the world's most pristine natural places. The archipelago has a unique combination of endemic plants and animals, many of which still have little fear of humans, all under an equatorial sun but surrounded by cool seas. The islands' impact on Darwin is clear from the start of his natural history discussion on pp. 377-378 including the suggestive line "Hence, both in space and time, we seem to be brought somewhat near to that great fact—that mystery of mysteries—the first appearance of new beings on this earth."
In the back pages of his Galapagos notebook (12) Darwin recorded his initial observation concerning the mockingbirds which he knew from the mainland as the Thenca and which we have discussed above. Most importantly the jotting confirmed his recognition that the flora and perhaps the fauna were South American types:
|| The Thenca very tame & curious in these Islds. I certainly recognise S. America in ornithology, would a botanist? — || (p. 30b)
This entry is probably the most famous in all the field notebooks, and the double scoring in pencil at the start and end show how important it was to Darwin himself. It was probably jotted on Charles Island on 25 September. In the Journal of researches this realisation was described in an important passage on p. 393.
As is almost universally known, Darwin was also very impressed with the finches (13) he encountered on the Islands. In the Galapagos notebook he made two short jottings about these birds, the first a simple mention of the large ground finch, also made on 25 September: "Gross-beakes" (p. 34b), the second a longer note about another species which was standing on a land iguana (Conolophus subcristatus): "Small Finc[h] picking from same piece after alights on back" (p. 43b). In the Journal of researches he explains the importance of these birds on pp. 379-80. Darwin saves the greatest significance of all these findings, namely that in the Galápagos there are noticeable differences between many of the plants and animals from different islands, for his important summary in the Journal of researches on pp. 393-395.
Even before publication of the Origin of species, Darwin's account of the Galápagos in the Journal of researches had made the archipelago famous and today they are recognized as one of the world's greatest natural laboratories for evolutionary study. There is no question that the species he encountered in the Islands were catalysts during 1836 and 1837 for undermining his belief in the 'stability' of species – indeed he says so very clearly in his private Journal and in the opening lines of theOrigin– but it was the previous three years he had spent in South America which had prepared his mind for this conceptual shift. Unfortunately the myth that Darwin 'discovered' evolution in the Galápagos is now so firmly entrenched in the popular imagination that it is probably impossible to dispel it.
CORAL REEFS
Our final selection is Darwin's longest essay on a single subject from the Journal of researches and is essentially a summary in chapter 20 of his monograph on Coral reefs (1842). The chapter deals with Keeling Atoll in the Indian Ocean, but ranges far and wide to consider the three types of reef from around the world which Darwin tied together for the first time by his single theory for their formation.
Coral reefs were a very hot topic in geology and hydrography in the 1830s and the Beagle's orders required that Captain FitzRoy take every opportunity to study them, partly because they could be a terrible hazard to shipping, as Captain Cook had experienced on the Great Barrier Reef of Australia in June 1770. Charles Lyell had also included a summary of the features of coral reefs in the second volume of his Principles of geology (1832) which Darwin had studied avidly since receiving a copy in Montevideo in November 1832. So when the Beagle set a southwesterly course from the Galápagos towards Tahiti, Darwin was eager to see reefs for himself. He had become convinced, especially after seeing fossil forests in the Andes which he believed must have been elevated by thousands of feet, that South America is rising from the sea. He had also been converted to Lyell's view that the Earth's crust is in constant oscillation so that if one region is rising other regions must be sinking to compensate. In his Santiago notebook while Darwin was in Chile he made the following entry in February 1835:
As in Pacific a Corall bed forming as land sunk. would abound with those genera which live near the surface. (mixed with those of deep water) & what would more easily be told the Lamelliform Corall forming Coralls. — I should conceive in Pacific wear & tear of Reefs must form strata of mixed. broken sorts & perfect deep-water shells (& Milleporae). — Parts of reefs themselves would remain amidst these deposits, & filled up with infiltrated calcareous matter. — Does such appearance correspond to any of the great calcareous formations of Europe. — Is there a large proportion of these Coralls which only live near surface. — If so we & may suppose the land sinking: (pp. 95-97)
We can see from this note that Darwin was already considering coral reefs in a theoretical light even before he had seen one. We can also see that he 'conceives' that corals only grow in very shallow waters in the tropics so where the land is sinking we will find dead coral in the sediments at the bottom of the sea. From this, if the Pacific is sinking, he is predicting that we will find such deposits on the bed of the Pacific. He is also predicting that if any of the 'great calcareous formations of Europe' (e.g. the Chalk and the Carboniferous Limestone) have this composition, they too will tell a tale of subsidence.
As recounted in the Journal of researches, after examining the fringing reefs of Tahiti in November, then stops in New Zealand in December and Australia in January and February 1836, the Beagle finally entered the lagoon at Keeling Atoll in the Indian Ocean in April and Darwin waded out onto the reef on the 5th. See his passage on pp. 458-459.
Darwin's work on Keeling and other coral reefs has been expertly described by many scholars, especially Armstrong (2004) and Sponsel (2016). After paying great attention to the types of coral brought up on the sounding lead at different depths around the reefs of Keeling and Mauritius, Darwin became certain that atolls are not – as Lyell and others generally believed – circular because they are built on the rims of sunken volcanoes but are in fact the end point in the gradual sinking of a tropical island. The rising island may acquire a fringing reef, as at Tahiti, which then becomes a barrier reef when the land starts to sink and finally an atoll when there is no longer any visible trace of the island on which the reef is built.
Darwin's theory showed how by applying a historical perspective to a series of present day related natural phenomena we may discover how they have evolved. The theory, which was proved correct by deep drilling in the 1950s, had the enormous added benefit that by plotting the distribution of the three sorts of reefs one could instantly see which parts of the world are rising and which are sinking. It was also of course within a few years to become the prototype for Darwin's theory of evolution by natural selection, which made special creation of species a redundant hypothesis.
We close this introduction with Darwin's wonderful final paragraph from the "Retrospect on our voyage" at the end of the book:
But I have too deeply enjoyed the voyage, not to recommend any naturalist, although he must not expect to be so fortunate in his companions as I have been, to take all chances, and to start, on travels by land if possible, if otherwise on a long voyage. He may feel assured, he will meet with no difficulties or dangers, excepting in rare cases, nearly so bad as he beforehand anticipates. In a moral point of view, the effect ought to be, to teach him good-humoured patience, freedom from selfishness, the habit of acting for himself, and of making the best of every occurrence. In short, he ought to partake of the characteristic qualities of most sailors. Travelling ought also to teach him distrust; but at the same time he will discover, how many truly kind-hearted people there are, with whom he never before had, or ever again will have any further communication, who yet are ready to offer him the most disinterested assistance. (p. 506)
May 2021
NOTES
1 That Darwin was the naturalist on the Beagle, rather than just a companion to Captain FitzRoy, has been conclusively demonstrated by John van Wyhe (2013). Darwin's 770-page manuscript Beagle diary was posted back in batches during the voyage and is now on display at Down House. It was edited for publication by Darwin's granddaughter Nora Barlow in 1933 and a slightly corrected version with an excellent introduction and notes was published by his great-grandson Richard Keynes in 1988. Scans of the manuscript are now available here alongside a full transcription by Kees Rookmaaker: Beagle diary.
2 There is a vast literature on the Beagle voyage and it is only possible here to mention a small selection. Recent detailed articles about Darwin's exploits include Allmon (2015), Egerton (2010) and Sponsel (2016). Darwin's religion during the voyage is discussed rather speculatively in Harley (2006), the best study of the Journal of researches as literature is Tallmadge (1980) and the best analysis of the changes made between the 1839 and 1845 editions is Gruber (1994).
Specialist books on Darwin's scientific discoveries include Armstrong (2004), Grant and Estes (2009), Herbert (2005), Keynes (2003), and Nicholas and Nicholas (2008). Darwin's views on enslavement and race are discussed in detail by Desmond and Moore (2009). Transcripts of Darwin's field notebooks, with detailed introductions are in Chancellor and van Wyhe (2009) and in Darwin Online and his correspondence during the voyage is available in the first volume of the Correspondence, with a selection in Burkhardt (2008). The best general history of the voyage is perhaps Taylor (2008) and we recommend Browne (2003) as the best all round biography of the first half of Darwin's life. Browne has also written the introductions to Burkhardt (2008) and (with Michael Neve) to the Penguin edition of the Journal of researches.
3 The near-sinking of the Beagle is depicted in the painting 'Sorely Tried' by John Chancellor (1925-1984).
4 There are beautiful photographs of Woollya and almost all the Patagonian locations visited by Darwin in Bartolomé and Gluckman (2007).
5 The toco toco or tuco-tuco described by Darwin 'as a rodent with the habits of a mole'. There are about fifty species of tuco-tuco. See specimen 1267 in Zoology notes, p. 165; listed as Ctenomys braziliensis in Mammalia, pp. 79-82.
6 Taupe is French for the mole. This is probably a species of Ctenomys.
7 Aperea (Cavia aperea) is the wild guinea pig and was described in Mammalia p. 89 as Cavia cobaia.
8 The theory of evolution of Jean Baptiste de Lamarck (1744-1829) was laid out in its greatest detail in his Philosophie zoologique (1809). Although sometimes both logically inconsistent and inadequately explained at many points, it is undoubtedly the first complete theory of evolution and the only academically respectable one before Darwin's. Lamarck's theory is summarised in our introduction to Lyell's Principles of geology. Darwin in his comments is mocking Lamarck's idea of the inheritance of acquired characteristics as the explanation of the blindness of cave animals. Darwin by 1845 believed that it was mainly natural selection which explained the blindness, although he always believed that the inheritance of acquired characteristics was possible.
9 "The Proteus aquatic reptile, neighbour of salamanders by its relations, and which dwells in deep and obscure cavities which are under water, no longer has, like the Aspalax, but vestiges of the organ of sight; remains that are covered and hidden in the same way. Here is a decisive consideration, relative to the question which I presently raise. Light does not penetrate everywhere; consequently, animals that usually live in places where it does not occur lack the opportunity to exercise the organ of sight if nature has provided it. However, the animals which are part of an organization plan in which the eyes necessarily enter, must have had it in their origin. However, since we find some among them who are deprived of the use of this organ and who have only hidden and covered vestiges of it, it becomes obvious that the impoverishment and even the disappearance of the organ are the results, for this organ, of a constant lack of exercise." [our translation]
10 The northern species are mentioned in August 1834 in the Valparaiso notebook (p. 2a) and the southern species appear briefly in the Port Desire notebook notes for Chiloe in November-December 1834 (pp. 58,83,101,178).
11 Darwin's final departure from the Islands on 17 October is imagined in John Chancellor's well known 1982 painting and appears on the cover of Chancellor and van Wyhe (2009).
12 This notebook is only known from a microfilm as it disappeared from Down House around 1980. (see Rookmaaker and Chancellor 2008).
13 Galapágos finches, commonly known as 'Darwin's finches'. This is the first known explicit recording by Darwin of the Galapágos finches and is here presumably referring to the thick-billed large ground finch listed as Geospiza magnirostris, Birds, p. 100, plate 36; see specimen 3331 in Zoology notes, p. 297.
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