Wednesday, July 11, 2012

Voyages of Discovery Sometimes Open Minds

For the past several weeks, I’ve been on an island, a big, very long one.  It is easy to lose sight of the fact that Long Island, New York, is an island.  Crossing the Verrazano Narrows Bridge is perhaps the clearest signal for me that this product of the last ice age is separate from the mainland.  Each summer I undertake a little voyage of discovery to this island’s flora and fauna, particularly the wildflowers along the lanes of the North Fork and the invertebrates whose shells decorate Flanders Bay.  (I have written several posts on this part of the island, including one about examining some of the shells in Flanders Bay by touch.)

But this island and my explorations bear little resemblance to the lands of the southern hemisphere and grand sagas of exploration described in a beautiful piece of historical writing that I just recently read.  There are a few books that must be shared and Darwin’s Armada:  Four Voyages and the Battle for the Theory of Evolution (2009) is one of them.  Written by historian Iain McCalman (University of Sydney), this is a masterfully and succinctly told story of four sea voyages that reshaped modern scientific thinking.  Four young Britons in the first half of the 19th century set sail for southern lands in search of adventure and discovery on voyages that served to awaken their latent scientific brilliance and propel them into the forefront of evolutionary science.  These were also voyages of self-discovery; they returned changed men.

The first of these voyages, Charles Darwin’s nearly five-year voyage to South America, the Galapagos, Australia, and the South Seas aboard the Beagle between 1831 and 1836, was the seminal event, not only for Darwin (1809 – 1882), but for the three who came after him, each of those inspired by Darwin’s book Voyage of the Beagle.  They were Joseph Dalton Hooker (1817 – 1911), Thomas Henry Huxley (1825 – 1895), and Alfred Russel Wallace (1823 – 1913).

Following McCalman's lead, I have gathered portraits (in the public domain) of each of these voyagers because one needs to keep in mind that they were young men.  Each shows the man shortly before or after his journey of discovery.

The portrait below of Charles Darwin was painted in the 1830s by George Richmond.  Darwin would have been in his very late 20s or early 30s and just returned.  (This has been downloaded from Wikimedia Common which states it is in the public domain.)

Joseph Hooker is seen below at age 32 in an image from Leonard Huxley's Life and Letters of Sir Joseph Dalton Hooker (Volume 1, p. 340, 1918).  This was some six years after the voyage that Calman describes in his book. 

Hooker served as assistant surgeon and botanist on Captain James Clark Ross’ vessel HMS Erebus during the 1839 – 1843 expedition to Antarctica, Australia, New Zealand, the Falklands, among other places in the southernmost regions of the globe.  (Ross considered him the ship's botanist, though it was an unofficial title.)  This voyage was part of a broader effort to map the behavior of the earth’s magnetic field.  Hooker truly modeled himself after the Darwin depicted in the pages of the Voyage of the Beagle, though his natural history expertise lay principally in botany.

Huxley is pictured below in a daguerreotype taken in 1846 when he was 21.  It is the frontispiece of Volume 1 of The Life and Letters of Thomas Henry Huxley, by Leonard Huxley (1901).  Here he is about to begin his voyage.
From 1846 to 1850, Huxley sailed on the HMS Rattlesnake as a surgeon’s mate.  This was a surveying expedition to New Guinea, the Coral Sea, and Australia, specifically the western side of the Great Barrier Reef.  Huxley’s natural history interests centered on the structure of extant creatures and their interrelationships.  His initial focus was on jellyfish, but his ethnographic interests came to the fore as the journey continued.

Finally, this is Wallace in 1848 when he was 25, just as his voyages were about to begin.  It is taken from his My Life:  A Record of Events and Opinions (Volume 1, 1905, p. 264).

Wallace, as far as I’m concerned, is a bit of an outlier in this group.  His was not one voyage of discovery, but several, and his initial motive was profit.  He was a collector of natural history specimens wherever he might find them, and so he took himself to those places where exotic and sought-after flora and fauna were – the Amazon and Southeast Asia.  During a period from 1848 to 1866, he was mostly abroad, collecting from, and thinking about, the disparate plants and animals he was observing and collecting.

McCalman’s accounts of these journeys of exploration are lively and informative, moving briskly through the details, but capturing the critical discoveries each man made and the maturation of their thinking about the history of the earth and its myriad inhabitants.  Further, the introductory pages to each provide the reader with a critical understanding of the social and economic backgrounds of each man.  There is no way to understand why Hooker and Huxley, in particular, fought so vigorously for evolution against the British scientific establishment if one doesn’t appreciate that they were in allegiance to tear down the walls of privilege and church-influence that surrounded that establishment and much of British society.  By the end of the evolution wars, all four of these men had become pillars of British science.

I came away with the strong sense that, because these men often explored islands on these voyages, they were primed to formulate (Darwin and Wallace) or embrace (Hooker and Huxley, the latter with some well-planned persuading) the explanatory power of the theory of evolution by descent with modification, powered by natural selection.  [Later edit:  Huxley's relationship to Darwin's theory is much more complex than I made it out to be here.  For instance, he never embraced natural selection as adequate enough to be the driving force behind evolution.  These and other points of tension are delineated in Sherri L. Lyons' book Thomas Henry Huxley:  The Evolution of a Scientist (1999).  Her book is a challenging read on Huxley's thoughts on evolution but well worth the effort.]  They learned to recognize the unique attributes of the flora and fauna in distinct, isolated locations, as well as those features that tied those living systems to those of other places.  That each man had undergone a passage of discovery was critical, according to McCalman, to what followed.

Through their South Seas odysseys, these four young, romantically minded amateur naturalists gained access to one of the richest natural laboratories on the globe.  They each discovered evidence from which to build new scientific theories, and each stored life-long memories of a common experience of hardship and pleasure that bound them together like shipmates.  Out of these southern adventures grew their friendship, their interlocking scientific interests, and finally, their joint participation in Darwin’s evolution war.  The southern oceans were the training ground of the seamen who would lead Darwin’s armada to ultimate victory.  (p. 12-13)

Though McCalman’s account of the evolution war itself is well done, it’s the story of the development of these young naturalists on their voyages to the southern hemisphere that makes his book so worthwhile.

In a curious way, a common jingle shell I found on the beach at the Great Peconic Bay (east of Flanders Bay) has led me to wonder about how frequently Britons, and Europeans in general, for that matter, in the early 19th century made these sea voyages to distant southern places and whether they were always as transformative.

My little, falling apart, paperback version of R. Tucker Abbott’s How to Know the American Marine Shells (1961), a still useful guide, describes the common jingle shell, providing its scientific name – Anomia simplex Orbigny.  At first blush, the most striking piece of information in this description is that, for this mollusk, the two valves are dramatically different.  The upper valve or shell is often strongly convex while the lower is flat with a large hole at the apex, where it is hinged to the upper shell.  The animal attaches itself to rocks, pilings, shells, and other surfaces through the hole in its lower shell.  The color of these generally smooth, thin shells varies from bright orange to a yellowy silver, often with a sheen.  The upper and lower shells can be colored very differently even in the same specimen.  Frankly, the upper and lower valves are so dissimilar that, though I could readily identify the upper as a common jingle shell, I was agnostic about what creature that bottom shell might be from.  In the picture below, the two valves of a single specimen are shown.    A small Atlantic slipper shell (Crepidula fornicata Linné) has attached itself to the upper valve.

With McCalman’s book fresh in mind, the taxonomic history of Anomia simplex had a different impact than it would have otherwise had.  Abbott followed the convention of identifying the individual who first named the shell as Orbigny.  The French naturalist in question is Alcide Dessalines d’Orbigny (1802 – 1857).  (As an aside, I think the naturalist’s full last name should be given in the scientific name for this shell – Anomia simplex d’Orbigny, but that seems to be infrequently done.)  It’s not hard to see why some aspects of his life seemed so familiar to me.  As a young man he showed great promise in natural science, in part, using the microscope to study foraminifera (how can I not be attracted to him when he’s sometimes referred to as the “father of micropaleontology").  His talent and skill prompted the Académie des Sciences and leading European naturalists, including Georges Cuvier and Alexander von Humboldt, to support him on a voyage of exploration to South America.  He sailed in 1826 and remained in South American for 8 years, exploring, collecting fossils, and amassing a huge collection of specimens from the region’s flora and fauna.  He ultimately reached Bolivia and stayed there for much of his time in South America.

It is only appropriate to include an image of d'Orbigny.  Clearly, he is young in this image, but I cannot read the script that appears below his portrait that might help me date it.  This is from the frontispiece to a work that d'Orbigny edited, titled Voyage Pittoresque Dans Les Deux Amériques (1841).  (Google Translate renders this title in English as Picturesque Voyage In The Two Americas.)

His account of his South American expedition appeared in 8 volumes published from 1837 through 1847.  A small translated excerpt from Voyage dans l'Amérique Méridionale appears in South America:  The Green World of the Naturalists, edited by Victor Wolfgang Von Hagen (1951).  It recounts his adventure traveling in Bolivia, from Moxos to Cochabamba.  In one passage, he describes his journey along a trail in the mountains with a wonderful blend of natural history and matter of fact observation about the perils he was facing.  (I presume the mountain range he mentions is part of the Andean Cordillera Oriental.  The entry is dated June 8th, but no year is given in this excerpt.)

Passing through deep ravines both to the east and to the west of the crest covered with eternal snows, I arrived at the highest point of the mountain range where, at an altitude of almost five thousand meters above sea level and in a Silurian terrain broken up by geological upheavals, I found to my amazement a great quantity of fossil sea shells.  In these savage regions everything is contrast; if I raised my eyes I could see above me peaks partly covered with snow, the blackish color of the rock emphasizing their whiteness.  Where I was passing I could see loose rocks and some rare plants such as geraniums, violets, malvaceas [malvaceae? – a plant family that includes the hibiscus], saxifrage plants and valerian which grew to a height only of a few centimeters above the ground. . . . I passed near a frozen lake between two ravines; and further on at the beginning of one of the lateral valleys I found the celebrated grotto of Palta Cueva under an immense rock which can shelter about ten people.  The numerous skeletons of mules scattered in all directions warned us clearly of the danger of staying there, a danger nevertheless which is difficult to avoid in view of the length of the journey and roughness of the trail.

D’Orbigny has come down in history as a preeminent taxonomist of invertebrates, naming many, many species.  He was a follower of Cuvier and, so, subscribed to the theory that species were created periodically, following catastrophes that wiped out earth’s previous cadre.  (The Natural History Museum, London, has a short and sweet backgrounder posted on d’Orbigny and his scientific thinking.)

But voyages of self discovery are not all the same, certainly not as transformative for some explorers as for others.  Apparently, d’Orbigny’s years in South America, exploring its geology and collecting its flora and fauna did nothing to challenge his basic views on the processes through which the earth changes and through which new species might arise.  To be fair, Darwin was primed to see things differently by his reading of geologist Charles Lyell’s Principles of Geology during his Beagle voyage.  (More on Lyell’s geology in a bit.)

D’Orbigny was in South America when Darwin came through, and though they did not cross paths, Darwin was aware of his presence.  In a letter dated November 24, 1832 and written in Montevideo, Darwin groused to John Steven Henslow (a naturalist and a clergyman)

. . . by ill luck the French government has sent one of its Collectors to the Rio Negro. – where he has been working for the last six month, & is now gone round the Horn.— So that I am very selfishly afraid he will get the cream of all the good things, before me. –

(Darwin Correspondence Project.  The editors at the Darwin Correspondence Project identify this French “collector” as d’Orbigny though the Darwin’s comment that he had “gone round the Horn” is a little puzzling.  What little I’ve read about d’Orbigny in South America doesn’t suggest he did that.)

In a later missive to Henslow (Lima, Peru, August 12, 1835), Darwin still complained about the Frenchman’s presence, but he realized that he could take advantage of what d’Orbigny might have collected and learned.

— I lately got hold of <  > report on M. Dessalines D’Orbigny’s labors in S. America.  I experienced rather a debasing degree of vexation to find he has described the geology of the Pampas, & that I have had some hard riding for nothing; it was however gratifying that my conclusions are the same, as far as I can collect, with his results.—  It is also capital, that the whole of Bolivia will be described. I hope to be able to connect his Geology of that country, with mine of Chili.— (Darwin Correspondence Project.)

Ah, the Pampas.  Darwin’s assertion that he and d’Orbigny agreed on the formation of the Pampas region was very premature and very mistaken.  He didn’t, and it was later a source of great irritation to him because d’Orbigny adhered to what Darwin considered to be geological reasoning conclusively disproved and discredited by Lyell.  In explaining how the Pampas (a huge geographic area of flat land, mostly in Argentina but including portions of Uruguay and Brazil) came to be, d’Orbigny, ever the disciple of Georges Cuvier, argued that entire region, Pampas and distant mountainous areas, were created in a sudden cataclysm.  Darwin believed unreservedly that the formation was the ancient estuary of the River Plata and was created slowly over time.

This was the quintessential distinction between the old and new in geology at the time.  Lyell had marked out the new thinking, positing that the geological features of the earth could be explained by the working of the same geological processes we see today over earth’s long history.  In his Geological Observations on South America (1846), Darwin went to great lengths to disprove d’Orbigny’s hypothesis about the formation of the Pampas.  I read the following excerpt from the book as a wonderfully subtle snide remark (on the order of “how in the world could someone with such a reputation hold to such a ridiculous theory?”):

To my mind it is little short of demonstration, that a great lapse of time was necessary for the production and deposition of the enormous amount of mud-like matter forming the Pampas; nor should I have noticed the theory of a debacle, had it not been adduced by a naturalist so eminent as M. d’Orbigny. (p. 98.)

Though Darwin and d’Orbigny disagreed on the big things, theirs was still a productive relationship (despite how much the Frenchman’s beliefs got under the Englishman’s skin).  In the same volume on the geology of South America, Darwin praised d’Orbigny and thanked him for the work he had done on some of the Andean specimens Darwin had collected during the Beagle voyage.

M. Alcide d’Orbigny, in his great work on South America, having published descriptions of many fossil mollusca, I took the liberty of writing to him to request that he would be so good as to look through my collection, and to this request, he acceded in the most obliging manner:  hence every species, with M. d’Orbigny’s name attached to it, has been identified by him.  Not only did M. d’Orbigny render me this important service, but, as will be apparent in the course of this work, he has favoured me with his opinion on the age of the several groups of fossils, and on the distinctness and affinities of many of the species:  considering that I had no claim on M. d’Orbigny’s time, I cannot express too strongly my sense of his extreme kindness.  (p. iv.)

Yes, the two might not see eye to eye on the fundamental issues, but Darwin recognized d’Orbigny’s taxonomic skills and, as was his want, enlisted his expertise.

Speaking of taxonomy, there’s a taxonomic story to be told about the Anomia simplex, one of inconsistency in the sources cited as to where d’Orbigny actually named and described the shell.  But it’s de minimis in the scheme of the stories told here, better to stick to voyages of discovery.

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