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361 [551] AGASSIZ
AGASSIZ [551] Even slight quakes would cause the mer cury to bob from side to side. Small iron floats were so attached that their move ments could be read off on a scale, and the intensity of the quake estimated. This was the first step to the modern seismograph. [551] AGASSIZ, Jean Louis Rodolphe (ag'uh-see) Swiss-American naturalist
May 28, 1807 Died: Cambridge, Massachusetts, December 12, 1873 Agassiz, the son of a minister, was de scended from a Huguenot family that fled France when the hand of Louis XIV grew heavy against them. He obtained a Ph.D. at Munich but went on to a med ical degree in 1830 at his parents’ insis tence. He remained, however, pro foundly interested in zoology and had al most succeeded in joining Humboldt [397] in one of the latter’s trips. After attaining his degree he went to Paris in 1832 and worked under Cuvier [396] in that scientist’s last years. He then took a post as professor of natural history at Neuchatel in Switzerland and while there worked with Cuvierian enthusiasm and detail on a huge work on fossil fishes. This was published in five volumes be tween 1833 and 1844 with the spon sorship and financial help (to the tune of 1,000 francs) of the dean of Europe’s scientists, Humboldt. This would have been enough to make his reputation as a naturalist and indeed it won for him the Wollaston Prize, presented to him by Lyell [502], but much more was in store for him, partly through the accident of his Swiss birth. The Swiss are acquainted with glaciers as few other Europeans can be, thanks to their home among the Alps, and, among them Charpentier [449] and Ve- netz [453], speculating on the boulders that occasionally dotted the North Euro pean plains, came to the conclusion that they had been brought there through gla cial action. This meant two things: that glaciers had once been far more exten sive than they are now, and that glaciers moved.
This notion Agassiz began by doubt ing, but fortunately he decided to exam ine matters for himself. He combined pleasure with business by spending his vacations in 1836 and 1837 exploring glaciers. What he saw made it seem most likely that glaciers did move after all. At the ends and sides of glaciers were accu mulations of rock; then, too, he found rocks that had been scoured and grooved, as though by the passage of glaciers (and their embedded pebbles) moving over them. He found such grooved rocks also in areas where no glaciers had ever existed in the memory of man.
In 1839 Agassiz found a cabin built on a glacier in 1827 and now located nearly a mile down the glacier from its original site. He drove a straight line of stakes clear across a glacier, driving them deep. By 1841 they had moved a good distance and formed a U—the ones in the center moving faster since the gla cier was held back at the edges by fric tion with the mountain wall. Agassiz came to the conclusion that glaciers not only moved, but that many thousands of years before, they had grown and moved out over areas to which they were now a stranger. In 1840, for instance, he found signs of glaciation in the British Isles. There had once been an Ice Age. Thus, geology re treated from the extreme uniformi- tarianism of Lyell in the previous de cade, though it was not till 1857 that Lyell himself finally gave in on this point. The minor catastrophes of advanc ing and retreating ice sheets did seem to take place and it was interesting that this particular catastrophe was a form of neptunism, though very, very far from the extreme form that had been ad vocated by Werner [355], Agassiz him self, however, accepted the Ice Age as a full Wernerian catastrophe, imagining re peated creations, perhaps as many as twenty. In 1846, thanks more to his work on fossil fish than on glaciers, Agassiz was invited to the United States to give a series of lectures in Boston. (Lyell, who
[551] AGASSIZ
LAURENT [553] had been visiting the United States, had suggested Agassiz for the purpose.) Agassiz came with the financial aid of a grant of 15,000 francs from King Fred erick William IV of Prussia and the best wishes of the aged Humboldt The success of the lectures plus his in tense desire to study the natural history of the North American continent led him to extend his stay, then to decide to remain indefinitely, particularly since a revolution in Prussia in 1848 (an un successful one) cut off his scientific al lowance. He spent a quarter century, mostly at Harvard University, where he proved a phenomenally good and popu lar lecturer, training a whole generation of American natural historians. In 1861 Agassiz became an American citizen as a gesture of pro-Northem sympathy when the Civil War started. Nevertheless, he believed human beings existed in various species and seemed firmly convinced of the inherent inferiority of blacks. In North America he found signs of ancient glaciation. It, like Europe, had undergone an Ice Age. Eventually he was able to trace out an ancient lake, no longer in existence, that had once cov ered North Dakota, Minnesota, and Manitoba. It is called Lake Agassiz in his honor. The Museum of Comparative Zoology at Harvard is also named in his honor. It was founded in 1858 around his natural history collection. The Ice Age, which Agassiz revealed to the world, is now known to exist in the plural. There have been a number of them in the earth’s history. The most re cent of them, filling the last half million years, was itself plural. Four times the ice advanced and then retreated, the last retreat being not much more than ten thousand years ago. Though Agassiz drew a spectacular picture of the past, he refused to accept the even more spectacular picture drawn by Darwin [554]. He was the most prominent biologist in the United States —as Owen [539] was in Great Britain— to oppose the notion of evolution by nat ural selection, though his work, willy- nilly, helped establish it. In 1915 Agassiz was elected to the Hall of Fame for Great Americans. By his grave in Mount Auburn Cemetery at Cambridge is a boulder from a Swiss gla cial moraine. [552] GUYOT, Arnold Henry (gee'oh) Swiss-American geographer
tel, Switzerland, September 28, 1807
February 8, 1884 After an education in Switzerland, Guyot traveled to Germany in 1825. There he abandoned theology for science and obtained his doctoral degree in 1835. In 1838 he met Agassiz [551] and through him eventually grew interested in the study of glaciers. In 1848, in the aftermath of the revo lutionary upheavals of that year, Guyot emigrated to the United States and set tled in Cambridge, Massachusetts, where he introduced the teaching of scientific geography. In 1854 he accepted a post as professor of physical geography and geology at Princeton. He was rescued from obscurity long after his death when the flat-topped sea mounts discovered by H. H. Hess [1304] were named for him in 1946. [553] LAURENT, Auguste (loh-rahnO French chemist
November 14, 1807 Died: Paris, April 23, 1853 Laurent, the son of a wine merchant, showed no interest in his father’s busi ness, and his teachers urged the disap pointed parent to allow his son to enter college. The young man earned a degree as a mining engineer in 1837 and served as assistant to Dumas [514] for a while, then became a professor of chemistry at Bordeaux in 1838. He was one of those who appreciated the point of view of Avogadro [412] and who fought to have Avogadro’s hypothe sis accepted as a guide to the determi nation of atomic weights—a point of
[553] LAURENT
DARWIN [554] view brought to a successful conclusion by Cannizzaro [668]. Laurent also fought against the ideas of Berzelius [425] concerning organic compounds. Berzelius divided all atoms and atomic groupings into positively and negatively charged entities and main tained that organic reactions depended on the manner in which such electric charges were brought together. Laurent, however, showed in 1836 that a sup posedly positively charged hydrogen atom could be replaced by a supposedly negatively charged chlorine atom with scarcely any change in essential proper ties. He defended this view in his doc tor’s thesis before Dumas and Dulong [441] among others. Dumas had held something of this view, but when the eminent Berzelius retaliated furiously, Dumas backtracked. Laurent, however, held firm and con tinued to accumulate evidence. For this he was rewarded by being barred from the more famous laboratories and being forced to remain in the provinces. He is supposed to have contracted tuberculosis as a result of working in poorly heated laboratories, and he died in middle age. His theories did not. He believed that families of organic compounds were built about certain atomic groupings and that electric charge had nothing to do with it. He classified organic compounds according to the characteristic groupings of atoms within the molecule and this view slowly won out over that of Ber zelius. Laurent even tried to present three-dimensional models of molecules. This, too, was ignored in his time but came into its own a generation later with Van’t Hoff [829], Liebig [532] eventually took up the new view though Wohler [515] held with Berzelius. Gmelin [457] finally adopted the Laurent point of view in his text book, and Beilstein [732] centered his massive encyclopedia of organic com pounds upon it. As Laurent’s theory grew more popu lar, Dumas, regretting his earlier pusil lanimity, attempted to take more than his fair share of the credit and there were lengthy arguments over this. The essential core of Laurent’s theory 364 has persisted to this day. Nevertheless, the concept of positively and negatively charged atoms and groups of atoms rose to prominence again with Arrhenius [894] a half century later, though in con nection with inorganic chemistry rather than with organic. The resonance theory of Pauling [1236], a century after Laurent, restored electric charge to its role in organic molecules, too, albeit in a much more sophisticated and subtle form than that envisaged by Berzelius. Laurent’s suggestion for naming or ganic chemicals formed the basis of the Geneva nomenclature adopted for or ganic chemistry by a congress held at Geneva in 1892 under the chairmanship of Friedel [693]. [554] DARWIN, Charles Robert English naturalist
February 12, 1809 Died: Down, Kent, April 19, 1882
Darwin was bom on the same day that Abraham Lincoln was bom four thou sand miles away in Kentucky. Darwin was bom in no log cabin, however. He was the son of a well-to-do physician and the grandson of the poet-physician, Erasmus Darwin [308], His other grand father was Josiah Wedgwood, famous for his porcelainware. Darwin showed no particular promise in his youth. At first he studied medicine but found that unlike his father and grandfather he had no aptitude for it. The sight of operations on children (per formed without anesthesia) horrified him beyond measure. He thought next that he would make a career in the church but found he had no aptitude for that ei ther. (His father angrily declared he would disgrace the family.) However, he had made natural history his hobby after reading Humboldt [397] and had grown gradually more interested in the subject during his stay at Cambridge. This was his road to fame. His first scientific work was partici pating in a geologic field trip led by Sedgwick [442]. Sedgwick recognized the [554] DARWIN
DARWIN [554] young man’s genius, but in later years was to be aggrieved and dismayed by Darwin’s theory of evolution. H.M.S. Beagle was about to set out for a voyage of scientific exploration in 1831 and Darwin was offered the post of ship’s naturalist, after the fashion of Brown [403] a half century before and Banks [331] a quarter century earlier still. The ship’s captain hesitated, for he was not favorably impressed by Darwin. In addition, Darwin’s father, larger in bulk (350 pounds) than in judgment, opposed the project as unfitting a future minister, but Darwin’s uncle Josiah inter vened and talked the elder Darwin out of his opposition. Darwin accepted, and off he went on a five-year cruise around the world under Robert Fitzroy [544], a cruise that lasted from December 27, 1831, to October 2, 1836. He suffered agonies of seasickness and permanently impaired his health. It is possible that he contracted trypanoso miasis on the trip, for his chronic symp toms in late life resemble those of this disease. Since these symptoms are not dramatic, Darwin has long been consid ered a hypochondriac and here he may have been done a great injustice. In any case, the voyage was the making of him, and through him it became the most im portant voyage in the history of biology. Darwin had already read some of the works of Lyell [502]. He had been intro duced to them by someone who felt Lyell’s views were ridiculous and thought Darwin would get a good laugh out of them. Darwin didn’t laugh. He was con verted to uniformitarianism in geology and to a clear realization of the antiquity of the earth and of the long ages through which life had had time to develop. Now, during the course of the voyage of the Beagle, his thoughts on the subject had a chance to sharpen. He noticed how species changed, little by little, as he traveled down the coast of South America. Most striking of all were his observations during a five-week stay of the animal life of the Galapagos Islands, a group of a dozen or so islands about six hundred and fifty miles off the coast of Ecuador. The Galapagos Islands con tained unusual giant tortoises, but what Darwin mainly noticed was a group of birds now called “Darwin’s finches.” These finches were closely similar in many ways but were divided into at least fourteen species. Not one of those spe cies existed on the nearby mainland, or, as far as was known, anywhere else in the world. It seemed unreasonable to think that by a special act fourteen different species were created on this small group of islands, fourteen species that existed nowhere else. Darwin believed that the species of finch on the nearby mainland, a seed-eat ing variety somewhat similar to the is land finches, must have colonized the is land eons before and that gradually the descendants of those first finches evolved into different forms. Some came to eat seeds of one sort, some of another; still others came to eat insects. For each way of life a particular species would develop a particular beak, a particular size, a particular scheme of organization. The original finch did not do this on the mainland because a great deal of compe tition existed in the form of other birds, while on the Galapagos Islands the origi nal finches found a relatively empty land.
But what could cause these evolu tionary changes? Lamarck [336] had believed that the inheritance of acquired characteristics was involved and that creatures deliberately tried to change in ways advantageous to themselves. Dar win could not accept that. He returned to England in 1836 with no answer (though he had come to pas sionate conclusions regarding Negro slavery, which he had witnessed in the Americas and which he detested with all the fire of a gentle, humanitarian soul). He was elected to the Geological Society and kept busy preparing several books on the voyage and the observations he had made. The first of these, now usu ally known as A Naturalist’s Voyage on the Beagle, published in 1839, was a great success (impressing Humboldt, for one, as Humboldt had once impressed Darwin) and made him famous. (Dar win always strove for a clear, unclut tered style. He believed “in making the style transparently clear and throwing el
[554] DARWIN
DARWIN [554] oquence to the dogs.”) He also an nounced a theory on the slow formation of coral reefs by the gradual accumu lation of the skeletons of corals, which was accepted by naturalists with enthusi asm. This theory was in opposition to one held by Lyell, but so pleased was Lyell with the clearly superior work of Darwin that the two became close friends. Darwin married his cousin Emma Wedgwood in 1839, and he joined the Geological Society of London, serving as secretary from 1838 to 1844. In this way he had an opportunity for close associa tion with Lyell and discussed with him the problem of evolution—for suddenly he had the key. On September 28, 1838, he read a fa mous book entitled An Essay on the
Malthus [387] forty years earlier. Malthus had maintained that human population always increased faster than the food supply and that eventually pop ulation had to be cut down by starva tion, disease, or war. Darwin thought at once that this must hold for all other forms of life as well and that those of the excess population that were first cut down would be those who were at a disadvantage in the com petition for food. For instance, those first finches on the Galåpagos Islands must have multiplied unchecked to begin with and would surely have outstripped the supply of the seeds they lived on. Some would have had to starve, the weaker ones first, or those less adept at finding seeds. But what if some could turn to eating bigger seeds or tougher seeds or, better still, turn from the eating of seeds to the eat ing of insects? Those that could not make the change would be held in check by starvation, while those that could would find a new untapped food supply and could then multiply rapidly until, in turn, their food supply began to dwindle. In other words, creatures would adapt themselves to different ways of life under the stress of environmental pressure. Every once in a while a change that would allow a better fit to a particular niche in the environment would permit one group of creatures to swamp another group and to replace them. Thus Nature would select one group over another and by such “natural selection” life would branch out into infinite variety, more efficient groups always replacing less efficient ones in each particular environ mental niche. (To be sure, Darwin had been thinking of natural selection before reading Malthus’s book, but Malthus had made him aware of just what a powerful force natural selection could be. It made Darwin realize that natural selection was sufficient to explain evolution.) But how did these changes come about? How could a seed-eating finch suddenly learn to eat larger seeds that others could not, or learn to eat insects? Here Darwin was on rough ground. There was no doubt that changes did take place. For one thing, Darwin, a country gentleman, kept pigeons as a hobby and had personal experience with the breeding of odd varieties of domesti cated animals. He could see that in any group of young there were variations from one to another—random variations in size, col oring, abilities. Darwin reasoned that it was through taking advantage of such variations, by deliberately breeding one and suppressing others, that over the generations man had developed larger, stronger, faster horses; cattle to give more milk and beef; sheep to give more wool; hens more eggs; and cats and dogs of odd and amusing shapes. Could not Nature substitute for man and make the same selection for its own purposes, much more slowly and over a much longer period, fitting animals to their environment rather than to man’s tastes and demands? (Empedocles [17] had suggested a very primitive version of this, something of which Darwin was aware.) By Darwinian notions the giraffe got its long neck not because it tried for one (as Lamarck had it) but because some giraffes were born with naturally longer necks and these got more leaves, lived better, and left more descendants, which inherited the naturally longer necks. A combination of natural variation and
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