3-4G The FhUosopluicul Socidy of Glasgov. 



This simple process embraces the principle of all the etching yet 

 done upon glass ; nevertheless, many useful modifications have been 

 introduced, both in the matters used as a resist and in the mode of 

 applying the acid. The gaseous fumes being combined or dissolved in 

 water, the acid is now generally applied in a liquid state. 



The application of these operations to the ornamenting of glass is of 

 very recent date, and for this purpose various methods have been 

 adopted. In some eases the figure to be produced upon the glass was 

 drawn upon it by a substance capable of resisting the acid, and then the 

 glass was submitted to the acid for a short time, after which the pattern 

 remained in relief. If the glass had a coloured veneer or coating up(Jn 

 it, the acid was allowed to dissolve the coating off, and the preseiwed 

 pattern was then left coloured upon the now colourless glass. Of course, 

 such a process as this required an artist and much time. The more 

 common process, however, to effect this pm-pose, was by stencilling, as 

 when the desired pattern was cut out in thin lead and laid upon the 

 glass ; the resisting coating or varnish was then brushed on the glass 

 through these cut parts, and, on removing the lead, the varnish remained, 

 forming the pattern. Or the reverse of this ; thin pieces of lead, paper, 

 or gutta percha are cut out, forming the pattern, and these laid upon 

 the glass with some adhesive matter easily removed ; the remainder of 

 the glass is then covered over with the resistmg varnish, and when dry 

 or hard these patterns are removed, the glass under them is cleaned and 

 the acid applied, and the figures or patterns are thus eaten out ; and if 

 the glass has been coloured by a veneer, the figure will appear white on 

 a colom-ed ground. Such are the principles, with different modifications, 

 by different manufacturers, upon which many of our window glasses are 

 ornamented. More recently a variety of patents have been taken out 

 for extending this branch of manufacture, some of them producing 

 articles of considerable beauty and design, although wanting in the 

 light and shade essential to a good picture. A recent modification 

 seems to be the subject of several patents, which is, to print a picture 

 from stone upon paper, using for an ink a mixture of resinous and oily 

 matters, thick, soft, and adhesive, and, when newly printed, the paper 

 is laid upon the glass, the ink-side down, and gently pressed, so as to 

 cause the composition to adhere to the glass. The paper is then 

 carefuUy removed; the figure thus transferred to the glass is examined, 

 and if any defect is seen, it is touched up with the hand, after which, 

 and while the ink is still soft, some charcoal dust is sprinkled 

 over it, which adheres to the resinous ink. When the ink gets com- 

 pletely'^ dried on the glass, all the loose charcoal is blown off, and the 

 glass, with the figure upon it, is subjected to the hydrofluoric acid. 



