IV. THE EARTH

In love with science, Halley had ventured into the mists of meteorology with an essay (1697) on trade winds, and a chart that for the first time mapped the movements of the air. He attributed these movements to differences in the temperature and pressure of the atmosphere; so the sun, moving apparently westward, carried heat with it, especially along the equatorial regions of the earth; the air rarefied by this heat sucked in less rarefied air from the east, and created the prevailing equatorial winds that Columbus had relied on to sail from east to west. Francis Bacon had suggested a similar explanation. George Hadley was to develop it in 1735 by adding that the greater eastward speed of the earth’s rotation at the equator creates a contrary westward flow of air.

The development of the barometer and the thermometer made meteorology a science. Guericke’s barometer rightly forecast a severe storm in 1660. Various hygrometers were invented in the sixteenth century to measure humidity. The Accademia del Cimento used a graduated vessel that received the moisture dripping from the outside of an ice-filled metallic cone. Hooke attached a grain bristle, or “beard”—which swelled and bent with increasing moisture in the air—to an indicator needle that turned as the bristle swelled. Hooke invented also a wind gauge, a wheel barometer, and a weather clock. This last instrument, designed on a commission from the Royal Society (1678), measured and recorded the velocity and direction of the wind, the pressure and humidity of the atmosphere, the temperature of the air, and the amount of rainfall; for literal good measure it gave the time of day. Armed with improved instruments, weather stations in diverse cities began to record and compare their simultaneous observations, as between Paris and Stockholm in 1649. Grand Duke Ferdinand II of Tuscany, patron of the Cimento, sent barometers, thermometers, and hygrometers to chosen observers at Paris, Warsaw, Innsbruck, and elsewhere, with instructions for recording meteorological data daily, and transmitting a copy to Florence for comparison. Leibniz persuaded the weather stations at Hanover and Kiel to keep daily records from 1679 to 1714.

The ingenious and inconclusive Hooke opened a hundred promising avenues of investigation, but was too poor in funds or patience to follow them to famous ends. We find him everywhere in the history of British science in the second half of the seventeenth century. Son of a minister who “died by suspending himself,” 28 he prefigured his vacillating diversity by painting pictures, playing the organ, and inventing thirty different ways of flying. At Oxford he took to chemistry, serving as assistant to Robert Boyle. In 1662 he was appointed “curator of experiments” for the Royal Society; in 1665 he was professor of geometry in Gresham College; in 1666, after the Great Fire of London, he took to architecture and designed several major buildings—Montagu House, the College of Physicians, and Bethlehem Hospital (“Bedlam”). After long poring through microscopes, he published his chef-d’oeuvre, Micrographia, (1665), containing a number of suggestive ideas in biology. He proposed a wave theory of light, helped Newton in optics, and anticipated both the law of inverse squares and the theory of gravitation. He discovered the fifth star in Orion, and made the first attempts to determine by telescope the parallax of a fixed star. He propounded a kinetic theory of gases in 1678, and described a system of telegraphy in 1684. He was among the first to apply the spring to regulate watches; he laid down the principle of the sextant for measuring angular distances; he made a dozen scientific instruments. He was probably the most original mind in all that galaxy of geniuses that for a time made the Royal Society the pacemaker of European science; but his somber and nervous nature kept him from the acclaim that he deserved.

Even in geology he had his moment of truth. He argued that fossils proved for the earth and for life an antiquity quite incompatible with the Book of Genesis; and he foresaw that the chronology of terrestrial life would someday be calculated from the differing fossils of successive strata. Most seventeenth-century writers still accepted the Biblical account of Creation, and some of them struggled to reconcile Genesis with the sporadic discoveries of geology. In An Essay towards a Natural History of the Earth (1695) John Woodward, after long study of his large collection of fossils, restored Leonardo da Vinci’s interpretation of them as the relics of plants or animals that had once lived on the earth, but even he thought that the distribution of fossils was a result of Noah’s Flood. An Anglican clergyman, Thomas Burnet, proposed (1680) a reconciliation between Genesis and geology by stretching the “days” of the Biblican Creation myth into epochs; this subterfuge proved acceptable; but when Thomas, gathering courage, went on to explain the story of Adam’s fall as an allegory, he found himself barred from ecclesiastical advancement.

Athanasius Kircher was both a good Jesuit and a great scientist; we shall find him brilliant in a dozen fields. His Mundus subterraneus (1665) charted ocean currents, suggested that underground streams were fed from the sea, and ascribed volcanic eruptions and hot springs to subterranean fires; this seemed to confirm the popular belief that hell was in the center of the earth. Pierre Perrault (1674) rejected the idea that springs and rivers have subterranean sources, and upheld the now accepted view that they are the product of rain and snow. Martin Lister explained volcanic eruptions as due to the heating and consequent explosion of the sulphur in iron pyrites; and experiment showed that a mixture of iron filings, sulphur, and water, buried in the earth, became heated, cracked the earth above it, and burst into flames.

The most prominent figure in the geology of this age was known to Denmark as Niels Stensen, and to the international of science as Nicolaus Steno. Born in Copenhagen, he studied medicine there and in Leiden, where he numbered Spinoza among his friends.29Migrating to Italy, he accepted Catholicism and became court physician to Ferdinand II at Florence. In 1669 he published a small volume, De solido intra solidum naturaliter contento, which one student has ranked as “the most important geological document of that century.” 30 Its purpose was to confirm the new view of fossils; but as a prelude Steno for the first time formulated principles to explain the evolution of the earth’s crust. Studying the geology of Tuscany, he found six successive strata. He analyzed their structure and contents, the formation of mountains and valleys, the causes of volcanoes and earthquakes, and the fossil evidence for formerly higher levels of rivers and the sea. The reputation earned by this book, and by Steno’s anatomical studies, led King Christian IV to offer him the chair of anatomy in the University of Copenhagen. He accepted, but his zealous Catholicism caused some friction; he returned to Florence, passed from science to religion, and ended as bishop of Titopolis and vicar apostolic for north Europe.

Meanwhile geography was growing, usually as a by-product of missionary, military, or commercial enterprise. The Jesuits were almost as devoted to science as to religion or politics; many of them belonged to learned societies, which welcomed their geographical and ethnographical reports. As missionaries they ventured into Canada, Mexico, Brazil, Tibet, Mongolia, China . . . They gathered and remitted much useful knowledge, and made the best maps of the areas they visited. In 1651 Martino Martini published his Atlas sinensis, the fullest geographical description of China yet printed; and in 1667 Athanasius Kircher issued a magnificent China illustrata. Louis XIV sent six Jesuit scientists, equipped with the latest instruments, to map China again; in 1718 they issued a vast map in 120 sheets, covering China, Manchuria, Mongolia, and Tibet; this remained for two centuries the basis of all later maps of those areas. The cartographical wonder of the age was the map, twenty-four feet in diameter, which Giovanni Cassini and his aides drew in ink on the floor of the Paris observatory (c. 1690), showing the precise location, in latitude and longitude, of all important places on the earth. 31

Some famous travelers belong to this period. We have already helped ourselves to Tavernier’s Six Voyages through Europe into Asia (1670), and Chardin’s Travels in Persia (1686). “In my six voyages,” wrote Tavernier, “and traveling by different roads, I had the leisure and opportunity to see all Turkey, all Persia, and all India. . . . The last three times I went beyond Ganges to the island of Java, so that for the space of forty years I have traveled above sixty thousand leagues by land.” 32 Chardin in one sentence anticipated Montesquieu’s Spirit of Laws: “The climate of each particular race is . . . always the primary cause of the inclinations and customs of its people.” 33 In 1670–71 François Bernier published an account of his travels and studies in India, and was accused of having shed his Christianity en route. 34 William Dampier buccaneered in a hundred lands and seas, wrote A New Voyage round the World (1697), and gave a cue to Defoe by telling how, on one of his later sallies, he piloted the vessel that rescued Alexander Selkirk from an otherwise uninhabited island (1709).

Geography played its part in the erosion of Christian theology. As accounts of other continents accumulated, the educated classes of Europe could not but marvel at the variety of religious beliefs on the earth, the similarity of religious myths, the confidence of each cult in the truth of its creed, and the moral level of Mohammedan or Buddhist societies that in some respects shamed the gory wars and murderous intolerance of peoples dowered with the Christian faith. Baron de Lahontan, traveling in Canada in 1683, reported that he had much difficulty in meeting criticisms of Christianity by Indian natives. 35 Bayle again and again quoted the customs and ideas of the Chinese or the Japanese in criticizing European beliefs and ways. The relativity of morals became an axiom of eighteenth-century philosophy; one wit described the travels of Jacques Seden the hermaphrodite, who, to his delight, found a country where all the inhabitants were homosexuals, who looked upon Europe’s heterosexuals as immoral and disgusting monstrosities. 36

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