Thomas Jefferson questioned the science of European doomsayers.

The environment is an endless source of anxiety in America these days. We worry about greenhouse gas emissions, hazardous wastes in our water supplies and toxic substances in our foods. But compared to the environmental concerns that plagued our nation at the very beginning of its history, these present worries do not seem all that overwhelming. Americans living in the early republic were informed by the best scientific authorities that something inherent in nature itself made the climate of the New World harmful to all living creatures, including the Indians and any newcomers from the Old World. This was not the conclusion of a few crackpots or of some fanatic European aristocrats eager to malign American republicanism. It was the conclusion of the greatest naturalist of the Western world, the French scientist George Louis Leclerc, comte de Buffon.

If Buffon’s scientific claims were true, then the chances for the success of the new American republican experiment were not good. Indeed, Thomas Jefferson was so offended by Buffon’s theories that he took great pains to refute them in the only book he ever wrote—Notes on the State of Virginia—and engaged in a spirited cross-Atlantic debate with the European naturalist that ultimately revolved around a desiccated moose. The exchange also brought to the fore an obsession Jefferson shared with most Americans of his era about the only humans native to the New World—the Indians.

Buffon included his profoundly pessimistic picture of the American environment in the rambling 36 volumes of his Natural History, published between 1749 and 1800. The American continents, said Buffon, were newer than those of the Old World. They had, it seemed, only recently emerged from the flood and had not as yet properly dried out. The American air was more humid than that of the older continents. Its topography was more irregular, its weather more variable, its forests and miasmic swamps more extensive. In short, America had an unhealthy climate in which to live.

Animals in the New World, observed Buffon, were underdeveloped—smaller than those of the Old World. America did not have any lions. The American puma was scarcely a real lion; it did not even have a mane, and “it is also much smaller, weaker, and more cowardly than the real lion.” The New World had no elephants; in fact, no American wildlife could be compared to the elephant in size or shape. The best that America had, Buffon wrote sarcastically, was the tapir of Brazil, but “this elephant of the New World” was not bigger than “a six-month-old calf.” All the American animals were “four, six, eight, and ten times” smaller than those of the older continents. Even the domestic animals introduced to America from Europe tended to shrink and dwindle under the influence of the New World’s climate.

Buffon also claimed that the American environment was responsible for the apparently retarded development of the native Indians, who seemed to be wandering savages stuck in the first stage of social development without any structured society. The Indians, Buffon said, were like reptiles; they were cold-blooded. Their “organs of generation are small and feeble.” The natives of the New World had no hair, no beards, no ardor for their females. Their social bonds were weak; they had very few children and paid little attention to those they had. In some way the moist climate of the New World had devastatingly affected the physical and social character of the only humans native to it.

Even more alarming was Buffon’s conclusion that the American environment posed a serious threat to newcomers from the Old World. For many 18th-century Englishmen and Europeans, the term “American” conjured up images of unrefined if not barbarous persons, degenerate and racially debased mongrels living thousands of miles from civilization amidst African slaves and Indian savages. Now the best scientific theories of the day seemed to reinforce these popular European images of the degeneracy of the New World.

Of course, most Americans in the generation following the Revolution did not let such theorizing seriously dampen their optimism and enthusiasm for the future. Instead, they reacted with indignant dismissal, exaggerated boasting or extensive scientific comparison. Perhaps it was true, conceded Jefferson, that America had twice as much rain as Europe, but in America, he said, it fell “in half the time.”

Yet some Americans seemed to have an underlying anxiety that the European critics might be right after all. There did seem to be something peculiar about America’s climate. The same regions with temperatures well below zero in winter could swelter in heat close to 100 degrees Fahrenheit in the summer; also, swings of 40 degrees Fahrenheit in 24 hours were not uncommon. No place in Europe had these sorts of radical variations in temperature. The American climate did seem to have more moisture. Humidity was often high, and heavy rainfall alternated with an unusual number of sunny cloudless days. Some speculated that these peculiarities were due to the existence of so much uncultivated land with so many dense forests in America. Europe’s climate had once been like America’s, it was thought, but once most of its trees had been cut down, its climate had changed.

The devastating yellow fever epidemics that erupted in American cities during this period, beginning with the catastrophe in Philadelphia in 1793 (which killed 10 percent of the population), were not duplicated elsewhere in the Western world. This led some Americans, including Jefferson, to conclude that the disease was indeed “peculiar to our country.”

Because the sun rarely shone in the middle and northern parts of Europe, the Europeans could “safely build cities in solid blocks without generating disease.” But America’s unusual atmosphere—the cloudless skies and the intense heat and humidity—fermented the garbage and filth in America’s cities, creating putrefaction that released effluvia and morbific fluids that bred disease; thus in America, said Jefferson, “men cannot be piled on one another with impunity.” He hoped that some good might come out of these epidemics of yellow fever: Americans might be inhibited from building the sorts of huge sprawling cities that existed in Europe.

Although America’s cities were scarcely crowded or dirty by European standards, many Americans decided that their unusual climate required their cities to be designed differently from those in the Old World. Urban renewal in the early republic was born out of these concerns about public health. Jefferson was especially worried about New Orleans, which promised to become “the greatest city the world had ever seen. There is no spot on the globe,” he said, “to which the produce of so great an extent of fertile country must necessarily come.” But unfortunately at the same time, “there is no spot where yellow fever is so much to be apprehended.” He decided that New Orleans and other American cities had “to take the chequer board” for a plan, with “the white squares open and unbuilt for ever, and planted with trees.”

Dr. Charles Caldwell, a Philadelphia physician who drew up even more elaborate plans for urban renewal to deal with the effluvia that presumably caused yellow fever, seems to have conceded that the Europeans were correct in their judgment about America’s climate. Instead of denying the Europeans’ charges, he turned them around by claiming that America’s climate was simply more stupendous than any other. “Nature,” he said in an oration in 1802, “was more gigantic in her operations” in America. “Compared to our own, how humble are the mountains, rivers, lakes, and cataracts of the Old World.” It stood to reason, he said, that America had bigger and more powerful diseases than other places. “Our diseases are not only more frequent but aspire to the same scale of greatness with our other phenomena.”

Americans’ preoccupation with the association of climate with these diseases grew out of their Enlightenment assumption that people were the products of experience and external circumstances. Since, as most people believed, humans had all sprung from the same origin, as recorded in Genesis, only the effects of the environment through time could account for the obvious differences among them. Even skin color was explained in environmental terms. Many believed that the Negro’s blackness came from the intense African sun—that somehow the African’s skin had become scorched. In the peculiar climate of America, some Americans thought, the African Americans’ skin would gradually become lighter, perhaps eventually white. The South Carolina historian David Ramsay, who believed that “all mankind [was] originally the same and only diversified by accidental circumstances,” claimed that “in a few centuries the negroes will lose their black color. I think now they are less black in Jersey than Carolina.”

All this emphasis on the power of climate had ominous implications for people living in America. If the climate of the New World was powerful enough to create peculiar American diseases or to affect the color of people’s skins, then Buffon’s charges were very serious indeed. And Jefferson felt obligated to address them head on.

In his (first published in a French edition in 1785; the first American edition Notes on the State of Virginia appeared in 1787, with two more in 1800 and five new editions in 1801), Jefferson systematically attempted to answer Buffon’s famous theories about the New World climate; in fact, he requested that one of the first copies of his book be delivered directly to the great naturalist. The parts of the book that today are often skipped over or eliminated in abbreviated editions— the tables and statistics about animals in Query VI—are precisely those parts that Jefferson considered central to his work.

Side by side, in order of volume, Jefferson listed the animals of the Old and New Worlds, accompanied by the weights of each in pounds and ounces. In almost every case the American animal is bigger. If the European cow weighed 763 pounds, the American cow was 2,500 pounds. If the European bear weighed 153.7 pounds, then the American bear weighed 410 pounds. As Jefferson described the various American animals—the moose, the beaver, the weasel, the fox—and found them all equaling or bettering their European counterparts, he got carried away with excitement and brought in the prehistoric mammoth to offset the Old World elephant. He even matched Buffon’s sarcastic reference to the tapir, “the elephant of America,” being but the size of a small cow. “To preserve our comparison, I will add that the wild boar, the elephant of Europe, is little more than half that size.”

Jefferson scarcely hid his anger at Buffon’s charges, and he raised question after question about the sources of the naturalist’s data. Who were those European travelers who supplied the information about America’s animals? Were they real scientists? Was natural history the object of their travels? Did they measure or weigh the animals they speak of? Did they really know anything at all about animals? Jefferson’s conclusion was clear: Buffon and the other European intellectuals did not know what they were talking about.

Jefferson was not someone who liked personal confrontations, but when he went to France in the 1780s as American minister he prepared himself for his first meeting with Buffon by taking with him “an uncommonly large panther skin.” He was introduced to Buffon, the curator of King Louis XVI’s cabinet of natural history, as someone who had combated several of Buffon’s theories. Jefferson did not hesitate in pressing Buffon about his ignorance of American animals. He especially stressed the great size of the American moose and told Buffon that it was so big that a European reindeer could walk under its belly. Finally, in exasperation, the eminent European naturalist promised that if Jefferson could produce a single specimen of the moose with foot-long antlers, “he would give up the question.”

That was all Jefferson needed, and he went busily to work, writing friends in America, imploring them to send him all the skins, bones and horns they could find, or better still, entire stuffed animals. Governor John Sullivan of New Hampshire took the most trouble of anyone, for he was commissioned to get the moose that was to demolish Buffon’s theories once and for all. Sullivan sent a virtual army into the northern wilderness of New Hampshire and even cut a 20-mile road through the woods to drag it out. By the time the specimen arrived in Portsmouth to be readied for its transit across the Atlantic, it was half rotten and had lost all its hair and head bones. So Sullivan sent along to Paris the horns of some other animal, blithely explaining to Jefferson that “they are not the horns of this Moose but may be fixed on at pleasure.”

Understandably, Jefferson was not entirely happy with the impression his bones and skins were making on Buffon. Although he asked his correspondents in America to send him the biggest specimens they could find, he continually apologized to Buffon for their smallness. Apparently, however, the specimens convinced Buffon of his errors, for according to Jefferson, the French naturalist promised to set these things right in his next volume. But he died before he could do so.

In 1789 Jefferson urged the president of Harvard to encourage the study of America’s natural history in order “to do justice to our country, its productions, and its genius.” In the mid-1790s on the basis of some fossil remains, probably belonging to a prehistoric sloth, he concocted the existence of a huge super-lion, three times bigger than the African lion, and presented his imagined beast to the scientific world as the Megalonyx, “the great claw.”

Meanwhile, others besides Jefferson wrestled with the problem of America’s environment. Indeed, at times it seemed as if the entire American intellectual community was involved in examining the creatures and the soil and climate of America. Clergymen in such obscure places as Mason, N.H., faithfully compiled meteorological and demographic records, and otherwise exclusively literary journals such as the Columbia Magazine and the North American Review published periodic weather charts sent from distant correspondents in Brunswick, Maine, and Albany, N.Y. Indeed, temperature-taking became everyone’s way of participating in the fact-gathering of enlightened science. Between 1763 and 1795, Ezra Stiles, president of Yale, filled six volumes with his daily temperature and weather readings. Countless other intellectuals felt the need to present papers about America’s climate. The Transactions of the American Philosophical Society for the year 1799 contained no less than six articles on the topic.

All this writing and temperature-taking showed that Americans were actually changing their climate. By cutting down forests and filling in swamps, they were moderating the extreme temperatures that had existed decades earlier. If Americans could change the weather, then they could change anything, or so they hoped.

Amidst all the discussion and debate, the issue finally came back to the Indian. Had America’s climate actually retarded the development of the only people native to the New World? Jefferson’s lifelong defense of the prowess and virtue of the Indian grew out of this passionate desire to protect the American environment against European aspersions. Buffon was wrong, he wrote; the Indian “is neither more defective in ardor, nor more impotent with his female, than the white reduced to the same diet and exercise.” The difference between the native peoples of America and Europeans was “not a difference of nature, but of circumstance.” There were good reasons why Indian women bore fewer children than whites, why the Indians’ hands and wrists were small, why they had less hair on their bodies; and those reasons, said Jefferson, had nothing to do with America’s soil or climate. For Jefferson, the Indian had to be “in body and mind the equal of the white man.” He could readily doubt the capacities of blacks, who after all came from Africa, but he could never admit any inferiority in the red men, who were products of the very soil and climate that would mold the people of the United States.

Jefferson, of course, never questioned that the Indians might not want to participate in the progressive course of history by giving up hunting and gathering and becoming assimilated into a society of white farmers. In his mind and in the minds of most enlightened Americans, his intentions were always pure. “We will never do an unjust act towards you,” he told a visiting delegation of Northwestern Indians in 1809 just before he left the presidency. “On the contrary we wish you to live in peace, to increase in numbers, to learn to labor as we do, and furnish food for your ever increasing numbers, when the game shall have left you. We wish to see you possessed of property and protecting it by regular laws. In time you will be as we are; you will become one people with us. Your blood will mix with ours; and will spread, with ours, over this great land.”


Gordon S. Wood, a historian at Brown University, won a Pulitzer Prize for The Radicalism of the American Revolution.

Originally published in the February 2010 issue of American History. To subscribe, click here