CHAPTER XIV

Science and Philosophy under Napoleon

I. MATHEMATICS AND PHYSICS

IN science the age of Napoleon was one of the most fruitful in history. He himself was the first modern ruler with a scientific education; and probably Aristotle’s Alexander had not received so thorough a grounding. The Franciscan friars who taught him in the military school at Brienne knew that science is more helpful than theology in winning wars; they gave the young Corsican all the mathematics, physics, chemistry, geology, and geography that they knew. Arrived at power, he restored Louis XIV’s practice of awarding substantial prizes for cultural achievements, and he revealed his background by giving most awards to scientists. Again following precedent, he extended his gifts to foreigners; so, in 1801, he and the Institute invited Alessandro Volta to come to Paris and demonstrate his theories of the electric current; Volta came; Napoleon attended three of his lectures, and moved the award of a gold medal to the Italian physicist.1 In 1808 the prize for electrochemical discoveries was given to Humphry Davy, who came to Paris to receive it, though France and England were at war.2 Periodically Napoleon invited the scientists of the Institute to meet with him and report on work done or in progress in their respective fields. At such a conference, on February 26, 1808, Cuvier spoke as the Institute’s secretary, with almost the classic eloquence of a Buffon, and Napoleon could feel that the Golden Age of French prose had been restored.

The French excelled in pure science, and made France the most intellectual and skeptical of nations; the English encouraged applied science, and developed the industry, commerce, and wealth that made them the protagonists of world history during the nineteenth century. In the first decade of that century Lagrange, Legendre, Laplace, and Monge set the pace in mathematics. Monge developed with Napoleon a warm friendship that lasted till death. He regretted the deterioration of the consul into an emperor, but bore it with indulgence, and even consented to be made Comte de Péluse; perhaps it was a secret between them that Pelusium was an ancient ruin in Egypt. He mourned when Napoleon was banished to Elba, and openly rejoiced over the exile’s dramatic return. The restored Bourbon ordered the Institute to expel Monge; it obeyed. When Monge died (1818) his students at the École Polytechnique (which he had helped to establish) wished to attend his funeral, but were forbidden; the day after his funeral they marched in a body to the cemetery, and laid a wreath upon his grave.

Lazare Carnot came under the influence of Monge when studying in the military academy at Mézières. After serving as “organizer of victory” on the Committee of Public Safety, and escaping with his life from the radical coup d’état of September 4, 1797, he found safety and sanity in mathematics. In 1803 he published Réflexions sur la métaphysique du calcul infinitésimal; and two later essays founded synthetic geometry. —In 1806 François Mollien made a revolution of his own by introducing double-entry bookkeeping in the Bank of France. —In 1812 Jean-Victor Poncelet, a pupil of Monge, joined the Grand Army in the invading of Russia, was captured, and adorned his imprisonment by formulating, at the age of twenty-four, the basic theorems of projective geometry.

Mathematics is both the mother and the model of the sciences: they begin with counting, and aspire to equations. Through such quantitative statements physics and chemistry guide the engineer in remaking the world; and sometimes, as in a temple or a bridge, they may flower into art. Joseph Fourier was not content with administering the département of Isère (1801); he wished also to reduce the conduction of heat to precise mathematical formulations. In epochal experiments at Grenoble he developed and used what are now the “Fourier Series” of differential equations—still vital to mathematics and a mystery to historians. He announced his discoveries in 1807, but gave a formal exposition of his methods and results in Théorie analytique de la chaleur (1822), which has been called “one of the most important books published in the nineteenth century.”3 Wrote Fourier:

The effects of heat are subject to constant laws which cannot be discovered without the aid of mathematical analysis. The object of the theory which we are to explain is to demonstrate these laws; it reduces all physical researches on the propagation of heat to problems of the integral calculus whose elements are given by experiment…. These considerations present a singular example of the relations which exist between the abstract science of numbers and natural causes.4

More spectacular were the experiments that Joseph-Louis Gay-Lussac made to measure the effects of altitude on terrestrial magnetism and the expansion of gases. On September 16, 1804, he rose in a balloon to a height of 23,012 feet. His findings, reported to the Institute in 1805–09, placed him among the founders of meteorology; and his later studies of potassium, chlorine, and cyanogen continued the work of Lavoisier and Berthollet in bringing theoretical chemistry to the service of industry and daily life.

The most impressive figure in the physical sciences of Napoleon’s reign was Pierre-Simon Laplace. It was not unknown to him that he was the handsomest man in the Senate, to which he had been appointed after his failure as minister of the interior. In 1796 he had presented in popular form but brilliant style (Exposition du système du monde) his mechanical theory of the universe, and, in a casual note, his nebular hypothesis of cosmic origins. More leisurely, in the five volumes of his Traité de mécanique céleste(1799–1825), he summoned the developments of mathematics and physics to the task of subjecting the solar system—and, by implication, all other heavenly bodies—to the laws of motion and the principle of gravitation.

Newton had admitted that some seeming irregularities in the movements of the planets had defied all his attempts to explain them. For example, the orbit of Saturn was continually, however leisurely, expanding, so that, if unchecked, it must, in the course of a few billion years, be lost in the infinity of space; and the orbits of Jupiter and the moon were slowly shrinking, so that, in the amplitude of time, the great planet must be absorbed into the sun, and the modest moon must be catastrophically received into the earth. Newton had concluded that God himself must intervene, now and then, to correct such absurdities; but many astronomers had rejected this desperate hypothesis as outlawed by the nature and principles of science. Laplace proposed to show that these irregularities were due to influences that corrected themselves periodically, and that a little patience—in Jupiter’s case, 929 years—would see everything automatically returning to order. He concluded that there was no reason why the solar and stellar systems should not continue to operate on the laws of Newton and Laplace to the end of time.

It was a majestic and dismal conception—that the world is a machine, doomed to go on tracing the same diagrams in the sky forever. It had immense influence in promoting a mechanistic view of mind as well as matter, and shared with the kindly Darwin in undermining Christian theology; God, as Laplace told Napoleon, wasn’t necessary after all. Napoleon thought the hypothesis somewhat nebulous, and Laplace himself came at times to doubt Laplace. Midway in his stellar enterprise he stopped to write a Théorie analytique des probabilités (1812–20) and an Essai philosophique sur les probabilités (1814). Nearing his term, he reminded his fellow scientists: “That which we know is a little thing; that which we do not know is immense.”5

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