1890.1 on the Photographic Image. 135 



experimenting on the subject of phosphorescence, Schulze observed 

 that by pouring nitric acid, in which some silver had previously been 

 dissolved, on to chalk, the undissolved earthy residue had acquired 

 the property of darkening on exposure to light. This effect was 

 shown to be due to light, and not to heat. By pasting words cut out 

 in paper on the side of the bottle containing his precipitate, bchulze 

 obtained copies of the letters on the silvered chalk. The German 

 philosopher certainly produced what might be called a temporary 

 photocrram. Whatever value is attached to this observation m the 

 develo'^pment of modern photography, it must be conceded that a 

 considerable advance was made by spreading the sensitive compound 

 over a surface instead of using it in mass. It is hardly necessary to 

 remind you here that such an advance was made by Wedgwood and 

 Davy in 1802.* The impressions produced by these last experi- 

 menters were, unfortunately, of no more permanence than those 

 obtained by Schulze three-quarters of a century before them. ^ 



It will, perhaps, be safer for the historian of this art to restrict the 

 term photograph to such impressions as are possessed of permanence : 

 I do not, of course, mean absolute permanence, but ordinary durability 

 in the common-sense acceptation of the term. From this point of 

 view the first real photographs, i. e. permanent impressions of the 

 camera picture, were obtained on bitumen films by Joseph Nicephore 

 Niepce, of Chalons-sur-Saone, who, after about twenty years' work at 

 the subject, had perfected his discovery by 1826. Then came the days 

 of silver salts again, when Daguerre, who commenced work m 1824, 

 entered into a partnership with Niepce in 1829, which was brought 

 to a termination by the death of the latter in 1833. The partnership 

 was renewed between Daguerre and Niepce de St. Victor, nephew of 

 the elder Niepce. The method of fixing the camera picture on a film 

 of silver iodide on a silvered copper plate— the process justly asso- 

 ciated with the name of Daguerre, was ripe for disclosure by 1838, 

 and was actually made known in 1839. ^ • • n 



The impartial historian of photography who examines critically 

 into the evidence will find that, quite independently of the French 

 pioneers, experiments on the use of silver salts had been going on m 

 this country, and photographs, in the true sense, had been produced 

 almost simultaneously with the announcement of the Daguerreotype 

 process, by two Englishmen whose names are as household words m 

 the ranks of science— I refer to William Henry Fox Talbot and 

 Sir John Herschel. Fox Talbot commenced experimenting with 

 silver salts on paper in 1834, and the following year he succeeded m 

 imprinting the camera picture on paper coated with the chloride. In 

 January 1839 some of his "photogenic drawings "—the first "silver 

 prints " ever obtained— were exhibited in this Institution by Michael 



* " All Account of a Method of Copying Paintings upoB Glass, and of making 

 Profiles by the Agency of Light npon Nitrate of Silver Invented by 

 T Wedgwood, Esq. With Observations by H. Davy." ' Journ. R. I. 180J, p. i/U. 



