Eigenh. Brief mit U. ("Laplace").
Autograph ist nicht mehr verfügbar
To a "Citoyen ministre", possibly Talleyrand, thanking him for his help in obtaining an Arabic astronomical manuscript by Ibn Yunis: "[...] le manuscrit arabe D'jbjunis, que possede la biliotheque de Leyde [...] mon objet est de tirer des manuscrits arabes toutes les observations & les lumieres qu'ils peuvent fournir relativement a l'astronomie du moyen age; c'est la science que les arabes ont le plus cultivée & et leurs observations peuvent seules remplir l'intervalle qui nous separe des grecs & des Caldeens [...]". - Professor Coussin, he continues, will translate the ms. and also another by Al-Battani. Laplace suggests that both works be printed by the Republican Press, which is equipped with the necessary types. - The 10th-century Egyptian astronomer Ibn Yunus is best known for having compiled tables of the planetary motions; the other figure identified by name, Syrian astronomer and scientist al-Battani, refined existing values for the length of the year and of the seasons. Laplace studied these well-known Arab scientists, whose important works improved upon the foundation set by such predecessors as Ptolemy. Laplace followed a similar course and is known to have studied a Yunus manuscript held at Leiden pertaining to eclipses - research, as noted on this page, that was translated by a professor of Arabic at the College de France. His reference to both men and their investigations of the heavens during the Middle Ages came just prior to the initial publication of "Traité de Mécanique Céleste", the French astronomer’s five-volume summary and extension of the work of his predecessors, published from 1799 to 1825. - With recipient's note at upper edge. From the Albin Schram collection.