## De l’Aberration apparente des E’toiles, causée par le mouvement progressif de la Lumiére [Clairaut] WITH La Figure de la Terre determinée [Maupertuis] in Mémoires de l’Académie Royale des Sciences Année 1737, pp. 285-318 [Clairaut]; pp. 533-597 [Maupertuis], 1741

Amsterdam: Pierre Mortier, 1741. 1st Amsterdam Printing. FIRST AMSTERDAM PRINTINGS OF 2 IMPORTANT PAPERS: CLAIRAUT ON STELLAR ABERRATION, THE FIRST DIRECT CONFIRMATION OF THE COPERNICAN THEORY with MAUPERTUIS & HIS OFFICIAL REPORT ON THE LAPLAND EXPEDITION TO MEASURE THE SHAPE OF THE EARTH. THE TRIPS CONFIRMED NEWTON’S DYNAMIC & SUPPORTED THE OBLATE SHAPE. 23 plates. Note that we offer the original, first Paris printing as well.

Both the French astronomer Alexis Claude de Clairaut and the French mathematician Pierre Louis de Maupertuis were involved in 18th century efforts to determine the shape of the earth; both published their findings in the this volume. To many controversy over the shape of the earth seemed a test between differing systems of natural philosophy — Cartesian and Newtonian. Though Newton and Huygens were working from differing theories of gravity, each calculated Earth to be slightly flattered at the poles. Writing in Principia, ”Newton had calculated from the Earth's rotational force at the Equator that its equatorial diameter should exceed its polar diameter by 0.44 per cent, or 27 km” (Hall "Revolution, 351). French astronomers, Cassini II among them, came to the opposite conclusion; with Cartesians, they believed the polar diameter of the Earth was the greater. The Cartesian argument stood for fifteen years until the French Royal Academy of Sciences questioned the reliability of using only local measurements to settle the matter.

To resolve the debate, Anders Celcius proposed an expedition to prove that the Earth flattens at the poles as predicted by Newton. In 1736, the Academy sent two expeditions to measure the meridian at the poles (Maupertuis & Clairaut to Swedish Lapland) and one to the equator (La Condamine to Peru).

Clairaut had studied the discovery of the aberration of light in 1725 by James Bradley; his discovery of the optical effect of the apparent motion of celestial objects is one of the most important in the history of astronomy. Clairaut realized that stellar aberration, caused by the motion of Earth in space and by the finite velocity of light, could be used on the expedition to correct observations of the motion of stars, thus aiding the accuracy of their data. But while Bradley discovered stellar aberration, he had not provided any proof, even theoretical Studying deeply, Clairaut was able to derive the proof and its underlying formulae from first principles; Maupertuis the used Clairaut’s formulas. Clairaut then published his proof and the details of how it was applied in Lapland in this volume. While some have argued that Bradley’s discovery “provided the first experimental confirmation of the motion of the Earth”, in reality his work had not provided even a theory— only Clairaut’s 1737 paper provided that. As a result, some argue that Clairaut’s paper represents “the first direct physical confirmation of the Copernican theory” (McGraw-Hill Encyclopedia).

Returning from Lapland, Maupertuis began to analyze the data he had amassed; his paper in this volume is the first printing of Maupertuis’s official report to the French Academy. Announcing values for a distance of one degree along the meridian in France and Lapland, his research clearly supported Newton’s hypothesis. “The message that the Lapland expedition brought home was clear: the length of a degree in Lapland was longer than the length of a degree in France… Maupertuis wrote: ‘The degree on the meridian that cuts the Arctic Circle being larger than the degree on the meridian in France, the Earth is a steroid flattened at the poles.’ Voltaire referred to Maupertuis as the ‘flattener of the Earth and the Cassinis’” (Murdin, Full Meridian, 64).

While Cartesians contested the results and pointed to errors, Maupertuis’s conclusions ultimately held. Item #982

CONDITION & DETAILS: Amsterdam: Pierre Mortier. 12mo. 23 plates. Full calf, 5 raised bands; gilt-lettered & tooled, red morocco spine label. Minor rubbing at the edges; very solidly bound. Clean & bright within. Near fine.

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Price:
$1,350.00
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