by Sarah Dry
His somber meditations do not long dominate his thoughts. Just as often he finds occasion for a cheering, even valedictory, feeling of unity with the forms of water around him. Traveling to the glacier on Christmas Day, he’d happily embraced the unity of the nature that surrounded him. “The heavens mostly grey,” he recorded in his journal, “a clammy vapour overspread the lake, and the red of the eastern sky had dusky cloud streamers drawn across it in different directions. . . . The hoofs clinked merrily upon the frozen road: right and left we were flanked by snow, but in the middle of the road, this was pressed to hard ice. As the valley narrowed, and the mountain walls came nearer this softened, and at some places had melted almost entirely away. As day advanced, the clouds vanished and a fine blue dome stretched overhead.”2
Soon after arriving, Tyndall and his guides headed for a rough chalet called Montanvert, close to the Mer de Glace, the glacier where they planned to make measurements. Tyndall had been here before, with the same aim, but never in winter. Soon snow was falling, astoundingly fast and thick. The men made it to the building where they would shelter, and Tyndall lay listening to the wind howling through the night. In the morning, he watched as the red light of the rising sun hit the clouds that fringed the steep ridge rising above the glacier. He recalled Tennyson’s “eternal” phrase, “God made himself an awful rose of dawn.”3 For a moment, the mountains burned like a pair of torches, and then the sun rose fully and the day began.
With daylight, the men started the work that had brought them here. Tyndall arranged his theodolite, a surveying tool for measuring locations precisely, in heavy snow, while the men advanced onto the glacier. Once in position, they set stakes in the snow along a line determined by Tyndall and his instrument. Heavy snow swirled across the glacier. Tyndall was able to communicate with the men only during brief moments when the air cleared. For the most part, all was whiteness and wind.
As the day continued, the quality of the snow changed and the flakes became blossom-like. They fell thickly on his coat, “soft as down.” Such prodigal beauty seemed to Tyndall a rebuke to humanity’s overweening pride. What could human beings matter to Nature if she is content to put on such shows where none can see them? It is typical of Tyndall that even as he considered his own insignificance, he recorded his unstoppable appreciation of the beauty.
After three hours in the snowy blizzard, Tyndall and his men managed to complete the measurement of a single line of stakes across the glacier. They returned the next day to record the distance they had traveled from their locations the day before. The weather remained awful, but Tyndall managed to make the measurements in the brief moments when it cleared. By midday, the work was complete. As he set back down the glacier, he turned and observed the line of stakes with a philosophical eye. “I knew of course that I had set them there, still the idea of intelligence and order that they suggested in the midst of that scene of desolation was pleasant”; he later recorded, “it seemed like the perception of law in apparent confusion.”4
The air atop the glacier was fresh and sere, as if all the moisture had been evacuated from it. Before he turned to the absorbing business of the descent, which required every ounce of his attention to be kept focused on the ice beneath his feet, Tyndall took a last lingering look at the great snow-filled valley and wondered at the ages it had taken for the miniscule action of molecules upon molecules to carve out the landscape before him. How long it had taken for these vast ice fields to accumulate was more than he, or anyone, could say, though some had tried. In a good year, some forty centimeters of new snow was laid down. How much was compacted by the weight of the snow that came after it, leaving a narrow sliver to represent an entire year of steady accumulation of snow? And how many of those tiny bands made up the bones of the glacier? It was impossible to know. Worse still, the glacier produced its own excretions, the freshwater that emerged from its lowest depths like a spring from the ground. This water was like a liquid breath, evidence that the glacier lived. It also destroyed the chance of a calendar written in the ice, since it was always the very oldest ice that had been slowly melting. And who could say for how long?
In the search for certain fundamental laws of nature in the chaos of the Alpine glaciers, Tyndall felt more alive than he ever did in London. The danger of the ice focused his mind, forcing him to think only about his next step and the one after that. Somewhat paradoxically, considering how many had already visited before he had, being on the glacier also allowed him to see himself as being alone in his scientific enterprise. If he was singular, he had a better chance at winning the prize, of explaining how sheets of ice could move across the earth. When he thought of the race to be first, the image of the virgin field of snow came to his mind, the glacier a pristine whiteness, whose “billows rose steep and pure and sharply crested.”
FIG. 2.1. John Tyndall in 1857, around the time of his first glacier investigations.
Of course he was alone neither literally, since he had his porters and his guides, nor figuratively, since he carried with him all the weight of previous theories that had come before, and all the fellow scientists who had put them forward, men who were simultaneously his imaginary collaborators and fellow combatants in the fight for priority, for influence. He selected his approach, and marshaled his resources accordingly. What he chose to do on the mountain was to undertake an open-air experiment. He would not simply look and record what he saw, as the geologists did, but would use his stakes, his theodolites, and his obedient assistants to subject the glacier to a particular kind of investigation—an experiment—more suited to physics than geology. As experiments go, this one was relatively crude. Measurements were made in yards rather than millimeters, and time measured in days rather than milliseconds. But it was still an experiment. He was trying to answer a specific question: How fast does the glacier travel at different locations? He would use the measurements he had stolen from the blizzard to support what he called his “theory of glacial movement” (others have different ideas). From a comparison of the locations of the stakes on the two days, he determined that the glacier had shifted 15.75 inches in that location. The same portion of the glacier, he knew from previous observations, had moved a little more than twice as fast during the summer.
The speed of the glacier would give an indication of the mechanism of its motion. What Tyndall had come to the Mer de Glace to do specifically was gather evidence with which to formulate and bulwark a theory that could explain all of the surprising facts about glacial motion. In the process, he hoped to claim victory for his theory over that of the religiously and socially conservative Scottish geologist James David Forbes, eleven years his elder and the man he considered to be his main opponent.5 Forbes had already said that ice moves like a viscous substance, but Tyndall wanted to show that this was merely an observation, not a theory. In itself, according to Tyndall, Forbes’s set of observations explained nothing. Worse, Forbes’s theory actively obscured the true nature of glacier motion. Tyndall wanted to show not merely what the ice seemed like (treacle or honey) but how it actually moved. Tyndall had chosen his destination for this winter expedition carefully. He came to the Mer de Glace because he wanted to be in the place upon which “the most important theoretic views of the constitution and motions of glaciers are based.”6 Many other scientists had stood upon this same glacier, the largest and most accessible in Europe, making their own observations and formulating their own theories. What all of these men had been wanting to know was the precise mechanism by which ice moves. Following in their footsteps was the only way to surge ahead. Tyndall must witness the same phenomena with new eyes, and submit them to new experiments, to prove that his understanding was superior to those of the men who had come before. If he went to another glacier and made his experiments, critics could always argue that the phenomena in question were different, that the results didn’t apply. But if he did them in the same place and showed that his account of glacier motion was superior, th
en he would have vaulted to the front of the pack.
FIG. 2.2. James David Forbes, Tyndall’s adversary in the matter of glacier motion, traveled to the Alps during the 1840s to make measurements on the ice.
FIG. 2.3. The Mer de Glace, in the French Alps, where John Tyndall and James David Forbes both made measurements on glacier motion.
Until recently, it simply hadn’t occurred to anyone, with a few important exceptions, to consider whether the ice could move, much less how it might accomplish such a thing. Those exceptions were the local people, mostly shepherds, who lived and worked in the mountains amid the glaciers. They noticed, year after year, the subtle and sometimes not-so-subtle changes in the glaciers that indicated movement. They saw the scratches on the sides of steep mountain valleys, the long piles of rocks discharged at the foot of the glacier. They lived with the occasional catastrophe, too, when the ice dams that preserved glacier lakes burst, sending huge amounts of water and terrifying blocks of ice tumbling through otherwise serene mountain valleys. But these people were not natural philosophers. They kept their thoughts to themselves, and it occurred to none of the small cadre who called themselves “gentlemen of science” to ask them what they thought.
* * *
It was only in the 1830s that the Alps started to matter to those who did not live and work there. Only then, when the mountains started to become more than a curiosity to men of science in places like London, were the seeds sown that gave Tyndall’s idea of journeying to the Alps an urgency that he was unable to resist. To a surprising degree, it was the hot and heavy world of industry, commerce, and trade that turned an obscure and icy corner of Europe into a major site of scientific inquiry. The tracks laid down by hungry railway companies as they sliced across Britain and the mines that dug ever deeper to find coal brought more and more secrets of the earth’s crust to light. These newly exposed strata and fossils raised increasingly hard-to-ignore questions about the earth’s history. The people who spent time scrambling over these new rocks with hammer and magnifying lens at the ready were concerned, first and foremost, with coming up with a good story to tell about the earth’s past. But the railway and mining companies also stood to make vast amounts of money on the basis of the advice these men could give them about where the earth’s hidden riches might lie. Soon, the rock-scramblers had a collective name for the study of the earth’s history—geology. These geologists looked to the Bible, with its compellingly dramatic narrative of the universal flood, as a resource that could guide and check their studies, but most were happy to read scripture metaphorically, translating a biblical day or year into thousands or even millions of years, if need be. Most important was the way that the intensely human Bible story—studded with contingent events—could still serve as an exemplar for a chronology of the earth’s history that was, in literal terms, vastly longer than anything it contained within it. The idea that the earth had a history that was separate from, and far longer than, human history was new and unfamiliar. But the structure of this astoundingly long history was not new at all. When Tyndall and his peers inherited this way of thinking, they were inheriting a way of looking at the earth that was rooted in the most familiar stories of all. This kind of earth history looked like the human history recorded in the Bible, a history marked by twists and turns, by the sense that, but for the intercession of chance events, things could have turned out differently.7
In addition to being provoked by the new evidence from below the earth’s crust, geologists in the early nineteenth century also started to look differently at things that were lying on the earth’s surface, which they had previously either ignored, discounted, or simply failed to see because they were not looking for them. Erratic boulders, of a type of stone alien to the landscape in which they were found, had always puzzled locals and provoked geologists to try to explain how they came to be where they were. Strange deposits were often found near these erratic boulders, a layer embedded with stones of every shape and size, arranged in no particular order. These disordered, unlayered beds were mystifying to geologists whose main tool for analyzing the structure of the earth was the comparison of fossils that had been laid down in stable strata.
The fragmentary nature of these so-called drift deposits, as well as erratic boulders that seemed to be scattered across the landscape without apparent order, posed a substantial challenge to the geologists trying to explain what caused them. For a long time, the leading explanation was a great flood, or series of floods, powerful enough to displace and transport even very large stones hundreds of miles. But the idea of a global deluge was too violent and too improbable for Charles Lyell, the pre-eminent geological thinker of the day. By 1835, Lyell had developed an explanation more compatible with the idea that geological change happened gradually as a result of causes that could be seen acting today. The unusual drifts, he said, were best explained by the existence of a huge sea, created by a gradual but dramatic lowering of the continents, which had once covered most of the globe, across which floated myriad icebergs, laden with a cargo of stones and clay. As the icebergs melted, Lyell imagined, they deposited their rocky loads on the seafloor. Because the movements of the icebergs were jumbled, their deposits were similarly chaotic. This theory had the merit of justifying the failure of geologists to bring clarity to their study of these drift materials. Clarity was elusive, according to the iceberg theory, because the mechanism of deposit was the jolly confusion of floating icebergs. Since icebergs had been seen in recent times, during a comparatively warm climate, his theory had the merit of not requiring a massively different climate in the past. “Adoption of this theory of ice-drift,” reassured Lyell, “does not of necessity require us to assume the former existence of a colder climate than that now prevailing in North America.”8 It made Lyell distinctly uncomfortable to imagine a past climate that was dramatically different from that of the current day.
FIG. 2.4. Tyndall, center right with beard and hat, stands with other members of the Alpine Club outside their club room in Zermatt. From Edward Whymper, Scrambles Amongst the Alps (London: John Murray, 1871).
Growing up, Tyndall heard of frequent voyages in search of the fabled Northwest Passage that could funnel British ships through the narrow inlets and icy seas of northern Canada to the other side of the world. Expedition narratives told of bergs so massive that ships floated alongside them for weeks at a time. These stories strained credulity at first, but, once authenticated, they were the perfect grist for Lyell’s theory. Indeed, Lyell drew liberally on reports of towering icebergs and massive ice sheets from expeditions to Canada and Greenland to construct a theory of sufficient grandeur to explain the widely dispersed geological puzzles. Sightings of icebergs as far south as forty degrees north suggested that very mild climatic change in the past could have produced the kinds of deposits that geologists were trying to explain. In 1819, William Parry brought back tales of enormous bergs that dwarfed the sailing ships—one estimated to be some 860 feet high (including the underwater portion). In 1822, whaling captain William Scoresby headed the first English expedition to lay eyes on the eastern coast of Greenland. The vast island backed by coastal mountains seemed to be topped by an ice sheet of unimaginable size. News came from the south as well, from ships in the Antarctic that sailed through a watery landscape strewn with icebergs. These reported visions—treated as facts thanks to the authority of the men who made them—fired the imagination of writers, poets, and playwrights. Stories of the ice helped bring the ice closer to home, to domesticate the ice for Tyndall and his contemporaries. Ice became part of popular culture. In 1816, a young Mary Shelley framed her gripping tale of a scientist’s creation of new life with a cautionary story of Arctic exploration and loss. Ice, in the early part of the century, was a source of new sensations that titillated and terrified the public in equal measure.
FIG. 2.5. Louis Agassiz, the Swiss geologist who promoted the bold new theory of the ice ages in the 1840s.
I
n 1840, Louis Agassiz made a bold suggestion that changed forever the way that everyone—scientists and the public—thought about ice. Synthesizing ideas that had largely been developed by others, Agassiz argued that erratic boulders and clay deposits could be explained by the action of a huge ice sheet that had once covered much of Europe and North America. The idea of an ice age raised many questions (had woolly mammoths really roamed the English countryside at the same time as humans?), but none more challenging than what it meant for the accepted history of the earth. The existence of enormous ice sheets in the past implied something that was almost inconceivable to most people at the time: that the earth might have been colder in the recent past.9
The reason this was such an unimaginable idea at the time was thanks to the work not of geologists but of another type of investigator. These men did not typically spend much time mucking about on the sides of mountains. Nor, when it came to it, did they spend much time on the glaciers of the Alps. Brothers William and James Thomson were among the most able of this brand of scientist. Armed not with stories but with mathematics, they made predictions that were best tested by experiments in the lab, where the precision of their analysis could yield spectacular results. Unlike the geologists, who saw history as a product of countless contingent accidents, these men saw time as ahistorical and uniform, the kind of time that unfolded in the belly of a steam engine. Their sacred text was Newton’s Principia Mathematica, and they hoped to do for the earth’s physics what Newton had done for celestial physics—to provide equations that could perfectly account for its motions.
