Burmese Glassware
Burmese Glassware
By adding small amounts of fluor-spar, feldspar and oxide of uranium to essentially the same ingredients used by Joseph Locke to produce Amberina, Frederick S. Shirley manufactured his popular translucent, homogeneous, shaded ware known as "Burmese." Mr. Shirley patented his formula for Burmese December 15, 1885, thus reserving the rights to produce it for the Mt. Washington Glass Company.
The addition of two pounds of uranium oxide made the ordinarily translucent white opal glass melt a pale yellow in color. Adding the small amount of gold, made soluable in a solution of aqua regia and colloidally dispersed throughout the entire batch, made the glass sensitive to thermal changes. After the article was formed from this glass it was allowed to cool below red heat and reheated at the glory hole. The reheated portions of the article struck a salmon-pink color which shaded down into the original body color of pale yellow.
Long before Shirley employed oxide of uranium as a coolant for Burmese the ingredient was being used by European and American glasshouses. Uranium imparts a very handsome wine-yellow color to glass, the metal stained by this oxide exhibiting a fine canary-green fluorescence when viewed by reflected light. In Bohemia it was known as "Annagelb" and "Chrysopras" glasses; the former a transparent uranium-yellow glass, the latter an opaque uranium-yellow with opalescent qualities. Annagelb was known at the Boston and Sandwich Works as "Canary yellow."
US $299.00
Gold too is a powerful colorant when introduced into a glass batch. At one time gold-ruby was very high in price, on the pretext of its content of the expensive metal, gold. This, however, is unjustifiable, on part gold being sufficient to transform fifty thousand parts of glass into a deep ruby metal. The tinctorial power of gold toward glass is so great that even one part in a hundred thousand will produce a light red glass. Moreover the solvent capacity of glass for gold is very small, and if an excess of gold be introduced into the batch, the glass will only dissolve sufficiently to give a deep ruby glass, the surplus being left behind as a fused button in the bottom of the pot.
The gold must always be in a liquid form and used as a very dilute solution. This solution is sprinkled over the sand used in the batch, the sand being well stirred to ensure that all particles are wetted with the solution. In view of this, the report of a gold ring accidentally fallling onto a gather of glass and producing Amberina coloring must be erroneous.
So little gold and uranium was used in the manufacture of Burmese glassware that an overemphasis of these facts can be quite misleading. From a batch weighing about two hundred pounds, containing less than $1.00 worth of uranium oxide and less than $3.00 worth of gold, hundreds of articles could be made. The amount of gold and uranium contained in each piece of Burmese is infinitesimal.
On June 16, 1886, Frederick Shirley's formula for Burmese was patented in England. Not long afterward Thos. Webb and Sons purchased a license to produce Burmese at their works in Stourbridge. The glass was named "Queen's Burmese Ware" and most of the articles produced by Webb were so marked, either with a paper label or incised in the glassed itself. On September 5, 1887, Thos. Webb and Sons registered a design for a flower-shaped top for vases and bowls which they produced in fancy colored wares - including Burmese. The registry number, 80167 can be found etched or engraved onsome of these wares.
For some time Stevens and Williams experimented to produce a similar ware without infringing on Mr. Shirley's patent. John Northwood II, whose father conducted these experiments, said they did produce a similar ware. It was, however, never marketed; in fact, in never got beyond the experimental stages at Stevens and Williams. A small bobêche on a shelf in Mr. Northwood's studio workshop is all that remains in England of this attempt to produce a competitor to Burmese.
Source: Nineteenth Century Glass - It's Genesis and Development
