JANSSEN, PIERRE JULES CÉSAR. - THE PHOTOGRAPHIC REVOLVER AND THE "FIRST FILM".

Passage de Vénus; Methode pour obtenir photographiquement l'instant des contacts, avec les circonstances physiques qu'ils présentent. (+) Présentation de quelques spécimens de photographies solaires obtenues avec un appareil construit pour la mission du Japon. (+) Présentation d'un spécimen de photographies d'un passage artificiel de Vénus, obtenu avec le révolver photographique. (+) Note sur le principe d'un nouveau revolver photographique. (4 Papers).

Paris: Gauthier-Villars, 1873, 1874, 1874 a.1882. 4to. No wrappers. In: "Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences", Vol. 76, No 11, Vol. 78, No 25, Vol. 79, No 1, Vol. 94, No 14. (3 entire issues offered). Pp. (677-) 732, pp. (1721-) 1780, pp. (5-) 72 and pp. (901-) 996. Janssen's papers: pp. 677-679, pp. 1730-31, pp. 6-7 and pp. 909-911. (The main paper having the title-page to the volume (vol. 79), stamp to title-page).

First printings of this series of epoch-making papers in which Janssen introduced the "PHOTOGRAPHIC REVOLVER" and its first successfull use leading to the "First Film" and hereby "realized one of the operations necessary for cinematography"(DSB).
In the first papers he conceived the idea of a device of historical interest, the photographic revolver, the technique of short exposures, which is announced here. The third paper is the epoch-making paper in which he specifically describes the "revolver" and its results, the "first film". The fourth paper is his responce to Marey's famous expriments with the "revolver" recording the flight of birds.

"A long barreled canon-like automatic camera was invented in 1874 by an outstanding pioneer of modern astronomical photography, Jules Janssen. Janssen used the revolving plate technique and called his camera a 'pistol'. Janssen's method used the forerunner of a number of 'gun' cameras with a slowly revolving plate and shutter operated by clockwork. The photos were taken every 70 seconds along the margin of the negative and he used his pistol to record a 48 image sequence of the transit of Venus across the sun at an exposure rate of 1.5 seconds."

"In planning for the observation of the transit of Venus, which he was to observe in Japan on 9 Deembe 1874, Janssen decided to substitute for visual observation at the time of transit a series of photographs taken in rapid succession, which would permit him to measure the successive positions of the planet in relation to the solar limb. He ordered the construcion of an apparatus consisting of three circular disks with the same axis: the first, pierced by twelve slits, served as the shutter;the second contained a window; the photographic plate, which was circular, was fixed to the third. The first two disks turned with a synchronized movement, the shutter disk continuously and the other irregularly in the intervals of time in which the window was not swept by a slit. A series of separate images laid out on a circle was thus obtained on the plate. In a general manner the apparatus provided an analysis of a motion on the basis of the sequence of its elemental aspects. Here Janssen realized one of the operations necessary for cinematography, which was invented twenty years later, and which required, besides analysis, the synthesis of images." (DSB).

Order-nr.: 49205