Mr. James Napier on a Xew Process of Ornameuling Class. 317 



This, as will be seen, leaves the picture in relief. It is necessary, in .ill 

 these processes, that the surface of this glass be either coloured, 

 enamelled, or gi'ound, otherwise these patterns would not be visible but 

 with difficulty, and at certain angles of light. 



My object in these remarks is to lay before the Society another and 

 more simple and cheap method of getting pictures or designs upon glass 

 by etching, and at the same time obtain pictures wherein the light and 

 shade of a print are preserved upon the glass. 



I take an ordinary picture or print upon paper, and paste it upon the 

 glass, the ink-side to the glass, with ordinary paste, such as starch, taking 

 care not to let air remain between them, and allow the paste to dr^^ 

 thoroughly. The glass, with the paper upon it, is then put into hydro- 

 fluoric acid, until the paper and paste are moistened, but not loosened ; 

 this requires from three to four minutes. I then wash the whole off, so 

 that no trace of acid may remain, when there is formed in relief a,/aC' 

 simile of the picture upon the glass. When the glass is finely ground 

 previously, the picture appears white ; when the glass has been stained or 

 coated with a coloured enamel, the picture remains coloured on a white 

 ground or clear ground. The veneering on the glass requires to be so 

 thin that the acid will dissolve it away in the short time that can be 

 allowed iu this process. The stained glass of Bohemia is well fitted for 

 this purpose. 



Although any picture or print (and old prints, as well as new) will 

 do, they are more suitable when the lines of the print are bold. This 

 is particularly necessary for window panes, or doors, or gas moons, as 

 they have to be looked at from a distance. 



. Again, the commonest printers' ink suits best ; hence the pictures 

 found in children's picture-books are found to serve the pm-pose ; but 

 when the best ink is mixed with some varnish before printing, it is 

 found equally good. 



It is a curious circumstance that we can make a negative picture — 

 that is, one in which the ink lines appear clear. This is done by keeping 

 it in the acid only half the usual time, and is accounted for, no doubt, 

 by the fact, that when the paste is merely moistened, and removed 

 immediately, the glass is whitened by the operation ; so that in the shoi't- 

 time operation the paste, where there is no ink, is in that state which 

 whitens the glass ; while the parts upon which the ink is have not been 

 affected. But in the longer time, the parts where there is no ink are 

 considerably affected and less whitened ; while the parts where the ink 

 is has only been newly affected, and are consequently in the maximum 

 state of whiteness. 



These operations have not yet been carried out to any great extent, 



