300 The Dawn of Light Printing. [July, 



navy, the two brothers settled down together at the little 

 town of St. Loup de Varennes, there to earn their bread in 

 the best way they could. During the first years, being both 

 of an ingenious nature, they turned their attention to 

 mechanical propelling contrivances, and invented a de- 

 scription of velocipede, termed by them a pyreolophore, 

 and this appeared to them so successful that Claude was 

 despatched to England in 1807 for the purpose of selling 

 the design. Left to himself, Nicephore continued some 

 experiments he had been making with lithography, then a 

 novelty brought forward by Senefelder, in Germany, and was 

 seized with the idea of elaborating a plan by means of 

 which a design reflected upon a stone would be permanently 

 fixed upon the surface. This idea led to the institution of 

 researches with the camera, so as to obtain the actual 

 result given by the retina of the eye, and his exertions in 

 this direction are detailed with much precision in a letter 

 to his brother Claude, dated 12th of April, 1816, of which the 

 following is a translation : — 



" I have profited by the short time we remain here to 

 construct a kind of artificial eye, which is simply a square 

 box, measuring six inches each way, and furnished with a 

 telescope-tube containing a lens. Without this apparatus 

 it would be impossible for me to judge of the merits of my 

 process." 



Here we have a description of a camera with movable 

 focus clearly described. On the 5th of May, Nicephore writes : 



" You heard in my last letter that I had broken the lens 

 of my camera, and that I had another one which I hoped to 

 make use of. In this I was disappointed, for the focus of 

 my other lens was shorter than the diameter of the box 



As I could not use my camera on account 



of the broken lens, I constructed another artificial eye with 

 a ring-box, measuring from sixteen to eighteen lines square. 

 This was fitted with a lens from my solar microscope, which, 

 as you know, formerly belonged to our grandfather Barrault* 

 one of the glasses possessing precisely the requisite focus. 

 By means of this little apparatus I obtained images most 

 clearly and sharply defined, reflected upon a field thirteen 

 lines in diameter. I placed my apparatus where I operate, 

 in front of the pigeon-house, and made an experiment in 

 the usual manner; I obtained on the white paper the whole 

 of that portion of the pigeon-house which is seen from the 

 window, and a faint image of the casement, which was less 

 brilliantly lighted than the exterior objects .... I am 

 well aware that there are many difficulties in my path — above 



