Frozen Earth: The Once and Future Story of Ice Ages (13 page)

I have been frequently urged during the past few years to draw up a statement of the principle incidents of my life. As this is a thing to which I have a strong aversion, I have hitherto declined. Induced mainly by the desire of my wife, I have at last agreed to comply with the wishes of my friends. Mrs. Croll will hurriedly jot down in pencil, to dictation, the facts as they occur to my mind. These jottings will probably never be reviewed or read over by me . . . it is a sort of work to which I am naturally ill adapted . . .

But in spite of their differences, Croll had a tremendous curiosity and an inner drive to learn and to explore knowledge that was in many ways at least the equal of Agassiz’s.
He had an ability to focus on a problem or a topic to the exclusion of almost everything else, and he was resolute in his pursuit of answers to questions he encountered in his reading.
At the age of twenty-one, while running a tea shop, Croll acquired a copy of
Freedom of Will
by the American philosopher-theologian Jonathan Edwards (1703–58).
He was so enamoured with the book that he read and reread it minutely in order to gain command of all of the author’s arguments.
He would spend an entire day on a single page.
Most of his spare time for a period of more than a year was devoted to Edwards’s book.
To his customers, he was an odd character: a large, shy man with a laborer’s frame and hands, running a tea shop but studiously reading philosophy whenever he had a spare moment.
It was clear to all—even to Croll—that he was not cut out for business, and his tea shop was short-lived.
But his ability to concentrate his intellect on nearly any subject he found interesting never wavered.
This trait served him well in pursuit of a theory for the cause of ice ages.
Based on his reading, Croll suspected that the cycles of glacial and interglacial climates might have an astronomical cause.
To investigate this possibility, he had to work out the mathematics of the Earth’s orbit around the sun.
His goal was to calculate how changes in the orbit would affect the amount of solar energy that is received by the Earth—if the changes were large enough, they would surely influence the climate.
In the 1800s, there were no computers or calculators available—all of the calculations had to be done, painstakingly, by hand.

Perhaps fittingly for a man whose name was to become linked with the ice ages, James Croll was born on a cold, snowy January night in 1821, near the end of a time that is now known as “The Little Ice Age” (about which more will be said in chapter 11).
But weather aside, there was little to indicate that this new entry into the world would make important contributions to our understanding of ice ages and climate.
Croll was born in rural Scotland; his father was a crofter who also worked as a stonemason.
It was a not an easy life.
Although the family was by no means destitute, neither were there any luxuries.
Young Croll was somewhat sickly, and only attended formal school classes intermittently.
He was educated partly at home, sometimes tutored by his parents and at others by a local schoolteacher.
But at least initially, he showed little real interest in learning.
However, when he began to realize the possibilities that education offered, his attitude changed.
Unfortunately, just at that time, at age thirteen, when he was finally eager to push on with his learning, he was forced to abandon further study.
He was needed to work on his family’s small farm.

Croll’s change of heart about education seems to have come from a single incident in 1832, when he was eleven.
It was characteristic of a number of events in his life that suddenly led him in new directions, often, it seems, on little more than a whim or passing impulse.
The 1832 incident occurred on a visit to the nearby city of Perth, where the young Croll found the very first issue of a small periodical called the
Penny Magazine
in a bookshop.
He promptly bought it, and was hooked—from then on he purchased issues whenever possible.
The little journal
was published by an organization that called itself “The Society for the Diffusion of Useful Knowledge,” and in the case of James Croll, it certainly succeeded in its aim.
Although Victoria was not quite yet queen when Croll stumbled on that first issue, it was a magazine and a venture typical of Victorian Britain: eclectic, wide-ranging, and meant to bring information about the wider world to the British public.
The issue that first caught young James’s eye in Perth contained, among other things, brief sketches of the lives of the French mathematician and philosopher René Descartes and the British physician who discovered the true nature of blood circulation, William Harvey; an article about Van Diemen’s land (now Tasmania); and a story about the grizzly bear that had just arrived at the London Zoo.
Whether it was the illustrations or the titles that attracted Croll’s attention is unknown, but from what we know about his studious habits in later life, it is likely that he read every word in the slim, eight-page issue.
For a country boy, it was a window onto lands beyond his own and a source of insight into the accomplishments of prominent intellectuals.
It was almost certainly one of the major inspirations for his own intellectual endeavors.
As a grown man, Croll went to some lengths to purchase a few missing back issues of
Penny Magazine,
which was then no longer published, so that he would own a complete set.

Stimulated by what he learned in
Penny Magazine,
but still tied down to work on the farm, Croll eventually purchased a few key books on philosophy and science and set to work to educate himself.
By the time he was sixteen, he was well versed in a wide range of subjects—remarkably so, considering that for much of this time, his days were occupied with physical labor.
Croll’s approach probably helped.
He was to remark later that he was generally not interested in the small details of a problem, but instead wanted to understand the underlying principles.
The details would fall into place if one knew the framework.

Croll eventually became a prominent figure in science and philosophy in Britain.
It is difficult to know whether he would have been even more productive had he been able to attend university and live the life
of a scholar.
As it was, the path from a self-taught farm laborer of sixteen to recognition as a leading intellectual was long and tortuous.

The sixteen-year-old farm laborer reading books on philosophy in his spare time really wanted to attend university.
But he had a very mediocre scholastic record and no formal training in Greek, Latin, or mathematics—important subjects for an aspiring university student in the nineteenth century.
He also had no money.
With characteristic logic and determination, although perhaps without pondering the consequences too carefully—another one of those new-direction-on-a-whim turning points in his life—Croll mulled over his situation for a few days and decided to become a millwright.
It seemed to him to be an occupation that would fit his abilities perfectly.
I know mechanics, he thought, therefore I’ll become a millwright.
What he hadn’t considered was that his penchant for understanding principles rather than details meant that he knew mechanics from a theoretical point of view, but had little feeling for the practical side of machines.
It must have been a rude awakening.
But he persevered, served out an apprenticeship, and joined a local firm.
“It was on the whole a rather rough life,” he reflected in his understated way.
The work took him around the countryside repairing mill machinery, sleeping in “on an average, three different beds a week.”
Bed is perhaps too luxurious a description for some of the sleeping arrangements Croll and his fellow mechanics endured; usually, they were put up in an unheated shed or barn.
To add insult to injury, his employers were having a difficult time financially, and the employees were not always paid.
After five or six years of slogging it out, he decided he had had enough and quit, resolving to try something else.

Croll was then twenty-one, unknown to anyone save a few farmers and millwrights in one small part of Scotland.
He was still as unlikely a candidate to make major contributions to science as he had been at birth.
It is all the more amazing, then, that when, in his sixties, Croll requested a small increment to his meager pension, a long list of luminaries from across the country petitioned to support his cause.
The duke of Devonshire, the marquess of Salisbury, the duke of Buccleuch,
Alfred, Lord Tennyson, Thomas Huxley, Joseph Lister, various members of Parliament, and many, many others lent their names to his request.
It was a startling testament to his emergence as an original and influential thinker, especially as he had never been a part of the stratum of society occupied by most of his supporters.

After deciding to give up his chosen profession as a millwright, Croll, for the next sixteen years or so, worked variously as a carpenter, a tea merchant, a self-employed electric battery maker, a hotel manager, an insurance salesman, and a writer for a newspaper.
None of these positions lasted very long, and they required him to move about from place to place in Scotland, and, at one point, to Leicester in England.
During most of this time, the itinerant Croll read voraciously and systematically, concentrating on his twin loves of philosophy and science.
He was much interested in the subject of will and the question of the existence of God.
During a spell of unemployment when he was about thirty-five, he organized his thoughts on the matter and wrote a book:
The Philosophy of Theism.
Croll was still an unknown to those who pondered such matters, and he published the book anonymously, probably on the assumption that it was better to be anonymous than to be an unknown writer.
Although he didn’t put his name on the book, he was otherwise not at all secretive about being its author.
The year was 1857 and this was his first real venture into print.
The subject matter wasn’t exactly likely to guarantee commercial success, and Croll had difficulty finding a publisher who was willing to take a chance on the book.
However, in the end, it got good reviews.
Although only five hundred copies were printed, Croll even earned a small sum in royalties.
But perhaps the most important effect of this book was that it brought Croll recognition as a significant intellectual.
He would no longer feel the need to publish his work anonymously.

A few years after his book appeared, in 1859, Croll’s meandering, frequently changing career finally settled into a semblance of normalcy when he took a position as caretaker at Anderson College, a private school and museum in Glasgow.
No more hard manual labor, no more
soliciting life insurance contracts from strangers, no more traveling about the country.
Croll’s position required a minimal amount of effort, physical or mental, and his salary, although small, was sufficient for his needs.
His brother, who was physically disabled and lived with Croll and his wife, helped him with the work.
The school had a well-stocked library, and the science section was extensive.
Croll had plenty of free time; for a man who loved to read and think it was heaven.
Almost forty, he was ready to begin making his mark in the field of science.

In his short autobiography, Croll recounts that when he took up his position at Anderson College, his primary intellectual interest was in philosophy and religion, the twin subjects of the book he had published a few years before.
He had plans to expand his earlier exploration of these topics in a more systematic way.
But instead he found the library at his new place of employment full of interesting works in science, and he decided to put his “metaphysics” aside for a while to investigate them.
As a teenager, when he first began his program of self-education, he had been much taken with physics and mathematics.
Through the newfound resources of the library at Anderson College, he wanted to reacquaint himself with these subjects, and to find out what was new in the world of science.
He became especially interested in research into the nature of heat, electricity, and magnetism, and, quite amazingly, within a few years began to make original contributions to these subjects.

The list of Croll’s scientific publications begins in 1861, just two years after he began his caretaker’s job in Glasgow.
His first effort was a paper on electricity in the respected
Philosophical Magazine.
Over the next twenty-five years, he contributed, on average, several articles annually to the scientific literature, many of them in the leading periodicals of the day.
Although it was undoubtedly a time when a determined “outsider” could make more of an impact on the world of science than is possible in today’s specialized world, Croll’s record is nevertheless impressive.
It is one that would bring credit to a full-time present-day academic.

Although Croll was retiring by nature, he had no hesitation in sending copies of his scientific papers to leading scientists throughout the
country and corresponding with them about his work.
He seemed secure in his scientific endeavors and confident in his own ability, in contrast to his feelings about some of his other ventures.
Recognition of his work was rapid.
In 1863, the prominent physicist John Tyndall, professor of natural philosophy at the Royal Institution in London, corresponded with Croll about some of the ideas expressed in his early publications.
Tyndall urged him to continue sending papers, writing, “I have no doubt that anything you send me will interest me.”

At about this time Archibald Geikie, one of Scotland’s most prominent geologists, published a lengthy and detailed description of glacial features in the country, concluding that they must be the work of great ice sheets that had flowed across the land in the past.
The work had been discussed in scientific circles in Scotland for several years before its formal publication, and, attuned as he was to current research in the physical sciences, Croll was undoubtedly well aware of it.
Here was a challenging and important unsolved problem to which he could turn his attention.
Croll thought initially that it would be a relatively straightforward task; “little did I suspect, at the time when I made this resolution [to investigate the causes of ice ages] that it would become a path so entangled that fully twenty years would elapse before I could get out of it,” he would later say in his autobiography.