444 ETCHING ON GLASS, 



A, Fig.5., Plate XVII., Vol. 1., is a cylindrical 

 leaden vessel, having a rim B all round it, made 

 like Count Rumford's steam rim for cooking 

 vessels, into which is put a little water. Into this 

 rim fits a cover c, having a pipe d coming from it, 

 which is inserted into a large oblong vessel e of 

 sheet lead, or iron well tinned, having a rim and 

 cover similar to the vessel A, only the cover has no 

 aperture. The fluate of lime powdered and the 

 sulphuric acid are put into the leaden vessel A, 

 which is placed upon a stand made of wire, having 

 a lamp to heat the contents of the vessel over it. 

 As soon as the gas is evolved it ascends, and not 

 being able to escape through the rim B, on account 

 of the water, which condenses a portion, it pro- 

 ceeds through the tube into the large vessel e, in 

 which is placed, upon stands of wire, the glass 

 prepared for etching by drawing through a var- 

 nish, as above described. 



In this vessel the gas collects, and acts upon the 

 glass : the rim with water prevents any noxious 

 fumes from escaping into the room. The vessel e 

 is placed upon a stand of such a height as to agree 

 with that of the lamp. In this manner the process 

 may be conducted with the utmost ease and 

 elegance. 



Beautiful ornaments may thus be etched on 

 glass, and applied to decorate windows, by paint- 

 ing the figure of the ornament on panes of glass 

 with enrgravers' stopping varnish, and then ex- 

 posing the panes to the action of the gass in the 

 vessel e. The gas will corrode all the surface of 

 the glass, except where the varnish has been put, 

 and give it much the appearance of ground glass, 

 which may be rendered more or less opaque by 

 lengthening or shortening the process. The parts 



