204 SEC. 7. LIGHT. 



A proof freshly pulled from an autograph, from a lithograph, from an auto- 

 lithograph, or from a copper-plate which is intended to be reproduced, is, by 

 this process, transferred to a copper- plate, and furnishes in a few minutes an 

 intaglio copy of the plate, as clean and good as the original, which is in no 

 wise injured by the operation. 



By means of this process : firstly, it is unnecessary to preserve the cum- 

 brous and fragile lithographic stones ; secondly, a plate in use may be repro- 

 duced so as to ensure repeated impressions ; thirdly, corrections may be made 

 on the copper, which could not be made on the original worn plate, exhausted 

 by repeated workings. The cost of reproduction on copper by Erhard's 

 process is infinitesimally small, and may be calculated at about 3 to 5 cen- 

 times per square centimetre. 



1. Album containing 36 maps and plans reproduced by this electro-chemical 

 process. 



2. 10 copper plates obtained by this process, the impressions from which 

 are shown in the album. 



946. Photoglyph! c engravings, 1853. 



H. Fox Talbot, F.R.S. 



947. Silver prints of views in Knoll Park. 



School of Military Engineering, Chatham. 



947a. Proof by Papyrotype Process. 



School of Military Engineering, Chatham. 



947b. Specimens of Enlarging Process. 



School of Military Engineering, Chatham. 



948. Second Proof of Photographic Engraving, 



obtained by M. Fizeau, without retouching, in 1843, and printed 

 in greasy ink. M. Fizeau, Paris. 



949. Daguerreotype Proof, fixed by M. Fizeau's process 

 with chloride of gold, by Mr. Hubert, in 1840. M. Fizeau, Paris. 



949a. Daguerrean Print, obtained by the continuous action 

 of red rays, without mercury. M. E. Bccquerel. 



9 SO. Photochromic Proofs (selection). M. Vidal, Paris. 



951. Early Talbotypes. 



Museum of Physical Apparatus, King's College, London. 



951a. Enamel Process, Specimens of. 



Wm. May land. 



952. Table of Specimens of Historical Records of 

 Photography. French Photographic Society. 



952a. Photography in its Application for Carto- 

 graphical Purposes. 



The Topographical Department of the Imperial Russian 

 General Staff at St. Petersbttrg. 



