29 November, 2009

Sunday Sensational Science

Getting Acquainted with Agassiz
Parte the Second: The Ice Man Cometh

In Parte the First, I introduced you to Louis Agassiz, who dominated my hometown by way of the peak named after him.  We explored the odd fascinating fact, and I promised you much, much more.

In this edition, we shall discuss his illustrious career, and some of the details that made me fall in love with the man.  Grab your ice axe and follow me after the jump, where we'll go cover the earth in ice with Agassiz.

Agassiz was a protege of Alexander von Humboldt, whom you may know through such things as the Humboldt Current.  If you're really current with your science history, you also know that von Humboldt provided the foundation for biogeography.  No small intellect, there.  This was the pattern of Louis's life: he surrounded himself with brilliant people.

He worked in Paris for Georges Cuvier, one of those men whose name comes up time and again when you're discussing such things as comparative anatomy and paleontology.  Well his name should - he was instrumental in establishing those fields.  You might think Louis Agassiz would be overshadowed by such giants, but no.  By the ripe old age of twenty-nine, he'd already made a reputation for himself as a paleontologist.  If he'd done nothing more with himself, his place in history would be secure just on the basis of that.

But then he discovered the ice ages.

We take it for granted now.  Of course the earth was icy.  We know that a good portion of it was covered in vast continental glaciers because we have films like Ice Age to tell us so.  Back in the 1800s, they didn't have Ice Age. They didn't even have an Ice Age.  They had some mountain glaciers, and they had erratic boulders.

Agassiz wasn't thinking erratic boulders when he moved down the street from Jean de Charpentier.  He was after fish in Lake Neuchâtel.  The only care he had for boulders was whether or not they contained fossil fish.  But there he was, living right near Charpentier, whose traumatic experience with a faulty ice dam had led him to investigate such things as glaciers and erratics and eventually had him publishing "Notice sur la Cause Probable du Transport des Blocs Erratiques de la Suisse."  (That's "Note on the Probable Cause of the Transport of the Erratic Boulders of Switzerland," more or less, for those who don't parlez français.)  Charpentier shared his ideas that huge sheets of ice had moved those out-of-place boulders around with Agassiz.

Louis Agassiz, father of the ice age, thought Charpentier's theory of the ice was absolutely absurd.  Whole districts covered in ice?  Enormous glaciers chauffeuring boulders around?  Really, Jean?  Louis laughed as roundly as all of Charpentier's other critics, of which there was no shortage.

So Charpentier took him walkies, and showed him a few things in the Valley of the Upper Rhone. Best thing to do, really.  Evidence that ice had altered the valley was undeniable, and that evidence was everywhere in the Swiss countryside.  Charpentier and Agassiz saw grooved and polished rock where glaciers had scraped over with their sandpaper undersides.  They found moraines in places where the ice had long ago melted away.  Rounded boulders were set down where no flood could have carried them.

Agassiz found the same evidence in a variety of places, enough to cause a wild leap of imagination.  When he put all the evidence together, he saw sheets of ice thousands of feet thick stretching from Ireland to Russia.  The skeptic became a firm believer.  When the Helvetic Society met in Neuchâtel that summer of 1837, president-elect Louis Agassiz surprised the gathered scientists by neglecting fishes for freezes.  He laid out his evidence and chronology of the glaciers.  Earth had, he announced, experienced an Epoque Glaciaire.  He'd discovered the Ice Age.

The assorted scientists listened to him lay out his case, and then gave their verdict. Von Buch threw up his hands in disgust and dismay.  Von Humboldt told him to go back to his fishes.  "Your ice frightens me."

Agassiz didn't take von Humboldt's earnest advice.  Ice didn't frighten him.  Much the contrary.  "Since I saw the glaciers I am quite of a snowy humor, and will have the whole surface of the earth covered with ice, and the whole prior creation dead by cold," he wrote to an English geologist.  "In fact I am quite satisfied that ice must be taken in every complete explanation of the last changes which occurred at the surface of Europe."  He chased the ice all over Europe, finding its traces in moraines on the plains of France.  Swedish boulders had emigrated to Germany.  If you knew what to look for, signs of the Ice Age were inescapable.

But it wasn't enough for Agassiz.  He traipsed every glacier he could find: by the Matterhorn, under the Eiger and the Jungfrau; he ambled up the Aar Glacier and discovered a message in a bottle in a cabin on the ice.  It told him that the monk who'd built the cabin in 1827 had returned after an absence of nine years, only to find the glacier had taken it upon itself to move his domicile two thousand feet down the mountain.

Agassiz and his colleagues measured the movement of the ice by driving a row of stakes straight across the glacier.  The glacier curved them.  Thus, Agassiz and company discovered that glacier ice flows like a very slow river, complete with more rapid flow in the center and around the outside of bends.

Von Humboldt's fear still didn't rub off on Agassiz.  When he came across a meltwater stream pouring into a deep hole in the glacier ice, he decided to have it diverted so he could have a look inside.  Sturdy men lowered him from a sturdy tripod; he didn't hit water for 20 fathoms.  He shouted for them to bring him up: they mistook his meaning and sent him underwater instead, before they realized what he'd actually been requesting.  Dripping and spluttering, he was hauled up past stalactites of ice so large that one falling would have killed him.  Colder and wiser, he said of the experience, "Unless induced by some powerful scientific motive, I should not advise anyone to follow my example."


Mountain climbers conquer peaks to be the first to the top, to prove themselves against the wilderness, for the joy of the challenge.  Agassiz conquered previously unsummited peaks just so that he could see the valley ice in its regional perspective.  This was, after all, an age in which one couldn't scrounge up some funding for an afternoon's worth of helicopter ride, or pull up Google Earth.  Induced by some powerful scientific motive, one did what one had to.

He headed down the mountains and scoured England, Scotland, Ireland and Wales for signs of ancient glaciers.  Everywhere he looked, he found them.  "The surface of Europe, adorned before by tropical vegetation and inhabited by troops of large elephants, enormous hippopotami, and gigantic carnivor, was suddenly buried under a vast mantle of ice, covering alike plains, lakes, seas, and plateaus," he wrote in his 1840 Etudes sur les Glaciers.  (That's Studies on the Glaciers, for those of you who don't parlez français).  Agassiz waxed poetic: "Upon the life and movement of a powerful creation fell the silence of death.  Springs paused, rivers ceased to flow, the rays of the sun, rising upon this frozen shore (if, indeed, it was reached by them), were met only by the breath of the winter from the north and the thunders of the crevasses as they opened across the surface of this icy sea."

That poetic language didn't win over doubting scientists.  Christian Leopold von Buch, celebrated geologist, paleontologist, and author of the first geological map of Germany, who'd won a reputation for his studies of volcanism, seems to have gone so far as to remove Agassiz's name from consideration for a professor's chair at the University of Berlin.  Sir Roderick Murchison, who had described and named the Silurian system and was thus considered a Big Name, got downright feisty over the matter, warning he was prepared to "make fight."  He at least made trouble, disparaging the very idea of glacial ice sheets before the Geological Society of London.  And Agassiz's old friend mentor von Humboldt stood fast in his opposition.  All that evidence Agassiz was trotting back with, he believe, was nothing but merely local stuff.

Everyone, it seemed, was a critic.  Until the day Agassiz got a letter from a friend.  "Lyell has adopted your theory in toto!!!" the letter said.  "On my showing him a beautiful cluster of moraines, within two miles of his father's house, he instantly accepted it, as solving a host of difficulties that have all his life embarrassed him."

You might ask what warranted no less than three exclamation points, and whether such effusive punctuation was necessary.  Geologists, however, know that no fewer were justifiable, and indeed, a case could be made for up to five.  Charles Lyell was the geologist of the time, whose Principles of Geology rather set the foundation for a whole new view of geology and made sense of the previously insensible.  Think of Albert Einstein or Stephen Hawking endorsing a new theory of physics, and you have an idea of what Lyell's effusive praise meant.  Perhaps three exclamation points were a bit on the restrained side, then.

And Lyell wasn't the only giant of science who got swept up by Agassiz's glaciers.  Charles Darwin hastened himself into the English countryside to see for himself if there were "marks left by extinct glaciers."  A letter to a friend soon followed: "I assure you, an extinct volcano could hardly leave more evident traces of its activity and vast powers....  The valley about here and the site of the inn at which I am now sitting must once have been covered by at least eight hundred or a thousand feet in thickness of solid ice.  Eleven years ago I spent a whole day in the valley where yesterday everything but the ice of glaciers was palpably clear to me, and then I say nothing but plain water and bare rock."

Agassiz had given scientists a new vision.  In retrospect, it seemed, he'd been pointing out the obvious, but before him, few had had the eyes to see, and no one had made the case with quite as much passion and literary force, backed by such hard evidence.  He did for continental glaciation what Darwin did for the origin of species, and it is, therefore, a tad bit ironic that Darwin's equally powerful case for evolution never swayed Agassiz.  But that's a tale for another Sunday Sensational Science.

Eventually, as inexorably as glaciers moved monks' cabins down mountainsides, Agassiz's theory of the Ice Age won over his critics.  In an 1862 address to the very Geological Society of London where Murchison had bashed Agassiz a scant couple of decades before, he now proclaimed his support.  He sent a copy of his address to Agassiz with a thoughtful little note: "I have had the sincerest pleasure in avowing that I was wrong in opposing as I did your grand and original idea of my native mountains.  Yes!  I am now convinced that glaciers did descend from the mountains to the plains as they do now in Greenland."

Agassiz got Murchison's kind note in America, where he'd relocated in 1846, there to found Harvard's Museum of Comparative Zoology and proclaimed the ice ages to the masses.  Imagine, if you will, this foreign scientist with his Swiss accent captivating American students with his stories of the ice.  He painted Boston covered by the glacier that deposited Cape Cod.  He covered Bridgeport with another glacier, which left Long Island behind.  When the ice retreated from Concord, it left behind Thoreau's Walden Pond.  Americans were enchanted by the ice.

Imagine, if you will, Agassiz paddling Lake Superior in a bark canoe, discovering features along its shores that wouldn't have been out of place in Neuchâtel.  The Hudson Highlands might as well have been the highlands of the Rhine.  America enchanted Agassiz as much as he'd enchanted America.  "The erratic phenomena and the traces of glaciers... everywhere cover the surface of the country.  Polished rocks, as distinct as possible; moraines continuous over large spaces; stratified drift, as on the borders of the glacier of Grindewald," he exulted.  Describing the Connecticut Valley, he wrote, "The erratic phenomena are also very marked in this region; polished rocks everywhere, magnificent furrows on the sandstone and on the basalt, and parallel moraines defining themselves like ramparts upon the plain....  What a country is this!  ....  I have had the pleasure of converting already several of the most distinguished American geologists to my way of thinking."

If he spoke in the language of evangelical religion, one can perhaps forgive him.  He was so passionate about the science of glaciers, so excited by their traces around him, and so swept up by geology as a whole that he'd teach geology to stagecoach drivers.  He believed that anyone could understand the nature of the earth, if only they were given a chance and a little assistance.  And he worked miracles.  He got Americans to pay him for his lectures on geology.  That American men and women wanted to hear scientific lectures wasn't the miracle: the fact they paid to hear them in French was.  Agassiz could speak English fairly fluently, but not fluently enough to do his glaciers justice.  Nothing for it but to deliver his lectures in his native language, and such was his power of presentation that Americans gladly shelled out for the privilege. Of course they would.  It didn't matter what language he was speaking in: geology moved him to tears, and that force of emotion left no one unmoved.

It probably didn't hurt that he'd often conduct his conversations with his Saturday Club with lit cigars in each hand.  You couldn't help but share his excitement.

Charles Darwin once told Henry Wadsworth Longfellow, "What a set of men you have in Cambridge.  Both our universities put together cannot furnish the like.  Why, there is Agassiz - he counts for three."

That he did.

Steven J. Gould, Time's Arrow Time's Cycle

As always, click on the illustrations for links to their sources.  I found easter eggs aplenty this time round - if you have the time, go explore.  And join me here Sunday after next, when we shall continue our odyssey with Agassiz in Parte the Third, wherein I explain how such a brilliant scientist, beloved even of Charles Darwin, could be a bleedin' creationist and still hang on to his science cred.

1 comment:

Cujo359 said...

That woodcut of an alpine glacier (sixth picture from the top) looked familiar for a moment, then I'd realized where I'd seen that pattern before. Here is an illustration. I saw it while making whipped cream. I'm guessing the reasons are similar - new ice or cream is pushed up against the old, forming ridges.

Interesting article, as usual, my dear.