Ueber die Ablenkung eines Lichtstrals von seiner geradlinigen Bewegung, durch die Attraktion eines Weltkörpers . .

Soldner, Johann Georg von (1776-1833). Ueber die Ablenkung eines Lichtstrals von seiner geradlinigen Bewegung, durch die Attraktion eines Weltkörpers . . . In Astronomisches Jahrbuch für das Jahr 1804 (1801): 161-172. Whole volume, 8vo. [4], 268pp. 2 folding plates. Berlin: bey dem Verfasser, und in Commission bey G. A. Lange, 1801. 200 x 115 mm. Half sheep, marbled boards ca. 1801, minor worming in front cover, lightly rubbed but sound. Fine copy. Small ownership stamp on title, occasional marginal annotations.

First Edition. Soldner's paper represents "the earliest work on the deflection of light in the gravitation field of the sun . . . On the assumptions that light has weight, and that it is deflected according to Newton's law of gravitation, [Soldner] computed the bending of a ray passing the limb of the sun." (Wylie, "The path of light in a gravitational field," Am. Math. Monthly 32 [1925]: 404). Soldner's calculations "are based on Newton's emission theory, according to which light consists of particles. On this picture the scattering of light by the sun becomes an exercise in Newtonian scattering theory. . . . Soldner made the scattering calculation, put in numbers, and found ? [the value of the deflection]= 0."84" (Pais, p. 200)-a result remarkably close to the actual value of 0."87. In 1911 Einstein, in his paper "Ueber den Einfluss der Schwerkraft auf die Ausbreitung des Lichtes" (Ann. Phys. 35: 898-908), used a different method but the same basic assumptions to come up with a similar value for this "Newtonian deflection." The gravitational bending of light by the sun was one of three tests Einstein posed in 1916 to confirm the general theory of relativity; in 1919, Sir Arthur Eddington and his collaborators became the first to observe and record this phenomenon. Pais, Subtle is the Lord, pp. 198-200.