Sur les photographies de la Lune obtenues au grand Équatorial coudé de l'Observatoire de Paris" and "Sur les photographies de la Lune obtenues au grand équatorial coudé de l'Observatoire de Paris" in Comptes Rendus, Vol. 119, 1894, pp. 130-135, pp. 254-259 WITH "Sur les photographies de la Lune et sur les objets nouveaux qu'elles ont permis de de découvrir" and "Sur la constitution physique de la Lune et l'interprétation de divers traits de sa surface, mis en évidence par les photographies" in Comptes Rendus, Vol. 121, 1895, pp. 6-12, pp. 79-85 de Puiseux, Pierre Henri; Loewy, Maurice

FIRST EDITION OF FOUR PAPERS IN WHICH THE FRENCH ASTRONOMERS PUISEUX AND LOEWY DETAIL THE PIONEERING WORK THAT LEAD TO THEIR MAGNIFICENT LUNAR ATLAS, A WORK REGARDED AS 'THE ULTIMATE ACHIEVEMENT OF NINETEENTH-CENTURY ASTRONOMICAL PHOTOGRAPHY" (The Photobook: A History, Vol. I, p. 54). Note that these rare papers preceed in publication the atlas itself (which did not begin publication until 1896). In July of 1894 and in the first of these four papers, Puiseux, Loewy, and the French Academy of Sciences announced a massive "project aimed to make the first complete large-scale photographic atlas of the moon. Earlier attempts at photographing the moon had suffered from difficulties with the sensitivity of collodion emulsions and with atmospheric 'blurring'" (E. A. Whitaker, Mapping and Naming the Moon, 151). Puiseux and Loewy's efforts succeeded far beyond anyone's hopes and their results astounded both the scientific and artistic communities. The papers in these volumes detail not just the scientific work and instrumentation design that enabled their project, but also a comprehensive account of their observations on the surface of the moon. "Some of these papers are devoted principally to a description of the instrument and its adjustment, others to general remarks on the subject of lunar photography and the difficulties which must be overcome in order to realize the full capabilities of the apparatus at their command. An interesting point in this connection is the method which they use for getting rid of the motion of the image in declination, by choosing for exposure times when the Moon's motion in declination is neutralized by the change of parallax. The rate of the driving clock is controlled by the observer, without stopping the clock, by means of a sliding weight on the pendulum. In some places the authors give the conclusions to which they have been led, by a study of their photographs, as to the nature and probably origin of the characteristic features of the Moon's surface" (The Astrophysical Journal, Vol. 5, 52). Operating at the end of the 19th century, photographic printing techniques had improved enough that the next logical step for Puiseux and Loewy was to get achieve a magnification similar to that achieved by selenographers (existing photographic telescopes had a plate size of 2-3 inches). Toward this end, Loewy and Puiseux designed and used a 'novel' telescope with a plate size of 7 inches in diameter that could be enlarged 8-15 times. Over the duration of the project they took more than 6000 photographs. Weather restrictions meant they had 50-60 days a year that were clear enough to photograph, and of those sessions only four or five negatives would be good enough to use" (Whitaker). Loewy didn't live to see the project completed, but when the atlas was finally finished in 1910, it was described as a "scientific and aesthetic tour de force of lunar photography" and remains hearalded to this day (Thomas, Beauty of Another Order: Photography in Science). ALSO PRESENT IN VOL. 121,the first edition of an important paper ("Nouvelles propriétés des rayons cathodiques") in which the French physicist Jean Perrin proves unequivocally not just that cathode rays transport charge, but that "cathode rays consist of negatively charged matter moving with considerably velocity" (Magee, Source Book in Physics, 580). CONDITION & DETAILS: Two volumes. Paris: Gauthier-Villars, 1894 and1895, 4to. In Comptes Rendus Hebdomadaires des Seances de L'Academie des Sciences Vol. 119 and Vol. 121, pp. 130-135, pp. 254-259 and pp. pp. 6-12, pp. 79-85. Ex-libris bearing only a deaccessioned stamp on the back of the title page and slight ghosting at the spine where a spine level has been removed. Quarto (11 x 8 inches; 275 x 200mm). Bound in clean full blue cloth, gilt-lettered at the spine. Solidly and tightly bound. Clean and bright throughout.