process, which, after many years of study and experiment, was 

 produced under the name of the Daguerreotype. The French 

 government appreciating the utility of invention, purchased it for 

 the benefit of all nations, granting to M. Daguerre a pension of 

 6,000 francs per annum for his life, and a proportional sum to M. 

 Isidore Niepc6e, the son of his former partner. Since the intro- 

 duction of the Daguerreotype, very many improvements have been 

 introduced, chiefly with a view to increase the sensibility of the 

 plates, on which the effect of light is now, with fine lenses, almost, 

 if not quite, instantaneous. 



As the possession of a good apparatus is an essential attribute 

 of success in taking Daguerreotype pictures, it will be well to 

 begin by describing the various articles which are necessary or 

 convenient for this purpose. They are as follows : 



CAMERA OBSCURA. 



The Camera Obscura, used for taking Daguerrotype Pictures (Fig. 



1,) is a wooden box, furnished in front with a brass tube, in which 



an achromatic lens is 

 made to slide. The 

 image is received on a 

 piece of ground glass 

 fitted in a frame, which 

 slides in a groove in 

 the back of the came- 

 ra, and the focus is ad- 

 justed by a rack- work 

 in the brass tube of 

 the lens. The frame 

 and glass may be with- 

 drawn, and another 



Fig. i. 



frame introduced, 



consisting of a wooden back, made to hold the silver plate, and a 

 sliding front which can be raised when the plate is to be submitted 

 to the action of the rays of light passing through the lens. This 

 Camera may be made of any dimensions, according to the diameter 

 of the lens employed. 



WILLATS'S IMPROVED PHOTOGRAPHIC CAMERA, (Fig. 2,) 

 Is a great improvement on that just described. The lens, 



