Buffon's Natural History. Volume 10 (of 10): Containing a Theory of the Earth, a General History of Man, of the Brute Creation, and of Vegetables, Minerals, &c. &c

In Short

This final volume of Buffon’s natural history presents an ambitious, systematic synthesis of the physical universe. Traversing animal variation, the mechanics of light and heat, mineral composition, plant biology, and planetary cooling, it seeks to uncover the foundational laws governing nature. Rather than treating subjects in isolation, Buffon charts how organic life and physical forces continuously alter the globe over vast epochs. The work endures as a masterpiece of Enlightenment science, bridging empirical experimentation and grand philosophy to assert that species remain permanent units of nature while individual lives fade.

The Story

The volume opens with an inquiry into animal variation, exploring how climate, nourishment, and human domestication cause species to branch off from primary trunks into collateral lines. Examining horned ruminants, rodents, and South American quadrupeds, Buffon interrogates whether distinct species share common lineages or represent unique creations. He argues that while domestic animals vary wildly under human influence and geography, certain unique genera reflect original, unalterable designs.

Shifted by this inquiry into the physical laws sustaining life, the narrative transitions to a rigorous study of heat, light, and fire. Buffon investigates how thermal energy diminishes across distance, contrasting the intense, immediate heat of terrestrial fires with the friction-generated warmth of solar rays passing through atmospheric air. He analyzes combustion and calcination as twin operational extremes of the same force, stretching from volatile phosphorus to indestructible gold. To ground these theoretical principles, Buffon records exhaustive physical trials: heating iron spheres of varying diameters to incandescence and measuring their precise cooling rates down to room temperature.

These physical forces directly inform his analysis of earth systems and chemistry. Buffon details how marine organisms transform water into solid matter, asserting that immense formations of limestone, marble, and chalk stem entirely from the discarded shells of ancient sea creatures. He conducts chemical trials on platina, arguing against contemporary views by proposing it is an alloy of gold and iron rather than a novel metal. Turning to optical experiments, he recounts constructing a complex arrangement of flat mirrors to focus sunlight, successfully igniting wooden planks over a hundred feet away to demonstrate solar power.

The scope then widens to botany, agriculture, and planetary physics. Buffon examines how winter frosts injure the internal heartwood of trees, offering practical methods for shielding delicate foliage using dry coverings and sheltered niches. He calculates the thermal history of the planets, estimating how long the earth has taken to cool from a molten state and evaluating the relative contributions of central terrestrial heat versus solar rays across different latitudes and elevations. Finally, the volume closes with high philosophical reflections on nature’s broader architecture. Buffon concludes that individual lives are ephemeral, whereas species endure as constant, unified entities sustained by universal physical forces.

How It Unfolds

The variation of species Buffon examines the structural resemblances among ruminants, rodents, and American quadrupeds, evaluating how climate, diet, and captivity alter living forms while identifying species that resist common origins.

The physics of heat and fire Through dynamic reasoning on radiation and air friction, Buffon explores the propagation of light and heat, establishing calcination and combustion as complementary actions driven by fire and atmospheric air.

Experiments on cooling spheres By heating iron bullets of scaled dimensions to white heat and measuring their cooling times, Buffon gathers empirical data to model the dissipation of thermal energy.

The biological origin of stone Buffon demonstrates how marine shell-animals extract liquid matter to form stony coatings, concluding that terrestrial marble, chalk, and limestone originate from accumulated organic remains.

Chemical trials and solar ignition Investigating platina to prove it is a natural alloy of gold and iron, Buffon also crafts an array of adjustable mirrors to ignite distant wooden targets using focused sunlight.

Vegetation, frost, and planetary time Analyzing how freezing temperatures damage timber, Buffon offers agricultural safeguards before calculating the earth’s gradual cooling period and the distribution of heat across global climates.

The general views of nature Buffon brings the work to a close by framing species as permanent, unified entities that transcend individual lifespans, sustained by fundamental forces and living particles throughout time.

The People

• Buffon (The Naturalist) wants to discover the unified physical principles governing the earth, minerals, plants, and animals; he faces the sheer complexity of natural phenomena and incomplete data, ultimately establishing a grand, empirically grounded system of natural history.
• M. Bouguer seeks to quantify the relative intensities of solar and lunar light; limited by the faintness of moonlight, he demonstrates that lunar illumination remains virtually cool even when condensed by powerful burning glasses.
• M. de Mairan aims to calculate the precise proportion of heat reaching the earth from the sun versus its internal core; constrained by climatic variations, his calculations help clarify how global temperatures equilibrate across summer and winter seasons.
• Messrs. Musschenbroeck and Fay seek to understand how atmospheric dew attaches to physical objects; challenged by unpredictable air currents, their observations reveal that dew floats in ambient air rather than simply falling perpendicularly.

In Its Own Voice

"The deer-kind whose horns are a sort of wood, and of a solid texture, although ruminating, and internally formed like those whose horns are hollow and porous, seem to form a separate family, in which the elk is the trunk..."

Buffon outlines the natural structural relationships that define animal families.

"...all our coral, rocks of calcareous stone, marble, chalk, &c. originally proceeded alone from the cast-off coats of those little animals."

The text highlights how tiny marine organisms build the geological foundation of the planet.

"Individuals of whatever kind, or however numerous, are of no estimation in the universe; it is species alone that are existences in Nature, for they are as ancient and permanent as herself."

Buffon summarizes his core philosophical view on the true scale and units of the natural world.

What It's Really About

At its core, the text investigates the fundamental unity and continuity of the natural world. Buffon argues against viewing physics, chemistry, geology, and biology as isolated realms, showing instead how single forces—like heat, light, and organic assimilation—manifest across all phenomena. The work interrogates the concept of time, shifting focus from fleeting human experience to the vast epochs required for planetary cooling and geological formation. By examining how living creatures actively build stone structures and how physical climate shapes animal bodies, the volume asserts that life and matter are locked in a continuous, reciprocal transformation governed by clear, universal laws.

Why Read It Today

Readers drawn to the history of science, Enlightenment philosophy, and environmental thought will find this volume deeply rewarding. It offers a rare, first-hand look at an epochal moment when empirical testing was actively reshaping human understanding of the cosmos. Buffon’s voice is remarkably confident, clear, and expansive, carrying the reader effortlessly from meticulous lab measurements of cooling iron bullets to breathtaking hypotheses regarding planetary history.

The reading experience requires some patience with eighteenth-century experimental precision, extensive numeric tables, and historic scientific theories that modern physics has since refined. Yet these very details lend the work its enduring charm, exposing the rigorous work of an extraordinary mind wrestling directly with the unknown. What remains long after reading is Buffon's profound sense of wonder at the scale of nature, paired with his unwavering conviction that human reason can decipher the vast, interconnected machinery of the world.