Since the publication in 1849 of my description of the _binocular camera_, a similar instrument was proposed in Paris by a photographer, M. Quinet, who gave it the name of _Quinetoscope_, which, as the Abbé Moigno observes, means an instrument for seeing M. Quinet! I have not seen this camera, but, from the following notice of it by the Abbé Moigno, it does not appear to be different from mine:—“Nous avons été à la fois surpris et très-satisfait de retrouver dans le _Quinetoscope_ la chambre binoculaire de notre ami Sir David Brewster, telle que nous l’avons décrite après lui il y a dix-huit mois dans notre brochure intitulée _Stéréoscope_.” Continuing to speak of M. Quinet’s camera, the Abbé is led to criticise unjustly what he calls the limitation of the instrument:—“En un mot, ce charmant appareil est aussi bien construit qu’il peut être, et nous désirons ardemment qu’il se répand assez pour récompenser M. Quinet de son habileté et de ses peines. Employé dans les limites fixées à l’avance par son véritable inventeur, Sir David Brewster; c’est-à-dire, employé _à reproduire des objets de petite et moyenne grandeur, il donnera assez beaux résultats_. _Il ne pourra pas servir, evidemment, il ne donnera pas bien l’effet stéréoscopique voulu, quand on voudra l’appliquer à de très-grands objets, on a des vues ou pay sages pris d’une très-grande distance; mais il est de la nature des œuvres humaines d’être essentiellement bornées._”[47] This criticism on the limitation of the camera is wholly incorrect; and it will be made apparent, in a future part of the Chapter, that for objects of all sizes and at all distances the binocular camera gives the very representations which we see, and that other methods, referred to as superior, give unreal and untruthful pictures, for the purpose of producing a startling relief. In stating, as he subsequently does, that the angles at which the pictures should be taken “are too vaguely indicated by theory,”[48] the Abbé cannot have appealed to his own optical knowledge, but must have trusted to the practice of Mr. Claudet, who asserts “that there cannot be any rule for fixing the binocular angle of camera obscuras. _It is a matter of taste and artistic illusion._”[49] No question of science can be a matter of taste, and no illusion can be artistic which is a misrepresentation of nature. [47] See _Cosmos_, vol. ii. pp. 622, 624. [48] _Id._ vol. vii. p. 494. [49] _Id._ vol. iii. p. 658. When the artist has not a binocular camera he must place his single camera successively in such positions that the axis of his lens may have the directions EL, EL′ making an angle equal to LCL′, the angle which the distance between the eyes subtends at the distance of the sitter from the lenses. This angle is found by the following formula:— ½_d_ 1.25 Tang. ½A = ———— = ———— D D