BOHEMIAN GLASS. 349 



glasses, etc. Another brilliant effect is" produced when a still hot bulb 

 of glass is rolled in finely pulverized aventurine glass,* and after this is 

 melted, and previous to the shaping of the vessel, is overlaid with a 

 coating of either colored or colorless glass. A still finer effect is ob- 

 tained with mica-brocade. The mineral mica, which has deceived so 

 many persons by its golden or silvery glitter, besides being applied as 

 a substitute for metallic bronze dusts, can be colored by the aniline 

 dyes in all manner of colors and shapes. The coarse powder called 

 brocade is used in glass-work, and the color-effect is produced by over- 

 laying it with colored glass. A bulb is blown, for example, out of 

 clear blue glass, is rolled in the brocade, which readily adheres to it, 

 and is then overlaid with yellow glass. The brocade will appear, when 

 looked at from within, of a steel color ; from without, of the color of 

 gold. Every flake will reflect the light, colored according as it is 

 looked at. 



A recent kind of decoration is shown in those glasses which appear 

 to be held together by a network of gold-thread. This is made by 

 preparing a skeleton of brass wire, and then introducing the glass aud 

 blowing it till its mass, having penetrated the interstices of the net- 

 work, spreads over it and tightly incloses it. The full effect is then 

 brought out by a subsequent etching away of the metal, and galvanic 

 gilding or silvering. Other metal ornaments, insertions, buttons, 

 drops, or figuring are often combined with this. They are cast in 

 steel-engraved forms of type-metal, which reproduce the finest details, 

 and are then galvanically coppered, silvered, or gilded. Another 

 pretty effect is obtained from the clouding which glasses mixed with 

 bone-ashes exhibit on being heated. If a bulb of this kind of glass is 

 blown into a metallic form which is dotted with projecting points, 

 a quick cooling ensues at these places, which leaves its mark after 

 the reheating and finishing in the shape of a regularly distributed 

 clouding. 



Only a little need be said, and that of the most modern operations, 

 of finishing, of the grinding, tarnishing, and polishing, ornamentation 

 with gold - leaf and platinum - foil, luster, and enamel coloring, etc. 

 One of the most noteworthy of these operations is that of tarnishing 

 by the centrifugal sand-blast. The objects to be treated by this process 

 are fastened upon revolving wooden pegs in the walls of a wooden 

 box ; the sand is introduced into the middle of the box, and is thrown 

 by rapidly rotating fans against its sides and against the glass figures. 

 After it has done its work upon the figures it falls upon the funnel- 

 shaped floor, to flow away and be lifted up again. 



A charming effect is produced at the Neuwelt houses by means of 

 a guillocheeing machine in which an engraver's tool is drawn in regu- 

 larly massed lines over the slowly revolving vase. The vessel has been 



* A glass containing bright metallic flakes, probably copper crystals in a brown 

 magma. It is made with rare perfection, by a secret process, in Venice. 



