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S2 - Fig. 117
Rated "rare"
Manufactured by Hobbs Brockunier & Company, © 1886
Burner marked "P & A HORNET/MADE IN U.S.A."

By Barry Schwartz

 Background and History:

Prior to 1886, opalescent glass was manufactured using a complex, slow and costly process. An appropriate mixture of glass was first blown into a ball-shaped mold, the surface of which had indentations. Once removed from the mold, the ball of glass with protrusions on its surface was allowed to cool and was then reheated to red-hot.  Because the protrusions on the surface of the ball cooled more quickly and to a greater degree than the main body of the ball, the reheating caused the protrusions to whiten, or become semi-opaque.  The now-opalescent ball of glass could then be blown into any desired shape by a skilled glass-blower.  In 1886, William Leighton, head of the manufacturing department of the Hobbs, Brockunier Glass Company and William Russell, patented a simplified and improved process for creating opalescent glass products (search for patent number 343,133 at www.google.com/patents).  Under the Leighton-Russell patent, a mold was created as close to possible as the desired final shape of the object.  The surface of the mold was indented to allow for the formation of the desired nodules or projections.  Molten glass (of an appropriate mixture) was pressed into the mold and then removed.  The resulting object was cooled quickly with a blast of cold air and was then reheated.  As in the original process, the protrusions on the surface of the object resulting from the indentations in the mold having cooled more quickly and more fully than the body of the object, turned the desired whitish color.  This improved process allowed for quicker and something closer to mass production of opalescent glassware without the need for highly skilled glass-blowers.

This attractive little finger lamp is shown in Ruth Smith's book, "Miniature Lamps II" in Figure 117 and in Catherine Thuro's first book, "Oil Lamps; The Kerosene Era in North America" on page 152 and was almost certainly made using the patented process described above.  Thuro attributes the lamp to the opalescent glass patent holder, Hobbs, Brockunier and Company of Wheeling, West Virginia (in 1888 the company changed its name to The Hobbs Glass Company).  We've seen the pattern of the glass in this lamp referred to as "Thousand Eyes", "Plain Windows", and "Coin Dot" (although the coin dot pattern appears to be reversed with the circles being opalescent and the matrix transparent).  Note that when you run your fingers over the surface of this lamp, you can feel the indentations which were an integral part of the process of manufacturing this glass.

 

 

An article in The Glass Encyclopedia expands on the above process description adding that this type of opalescent glass was made of two layers of glass with the thin outer layer - which fills the indentations in the mold - being made of a heat sensitive glass which turns milky white on heating.  The inner layer of glass, on this lamp, would have been cranberry glass - a type of glass that also requires reheating as described below.  The manufacturer of dark red, or "ruby" glass was a delicate and expensive process.  It required adding a solution of gold dissolved in Aqua Regia (a mixture of hydrochloric and nitric acids) to the molten glass mixture.  Getting the proportions of gold and acid correct was critical; minor errors resulted in an unattractive muddy color rather than the desired clear bright red color. The amount of the gold and acid solution added to the molten glass determined the darkness of the color.  Somewhat less solution resulted in a lighter colored "cranberry" glass while more of the solution resulted in a deep red "ruby" colored glass.  A further complication is that initially the resulting glass looks gray and only turns to the desired red color when the glass is reheated.   Because of the complexity of the process, "ruby" or "cranberry" glass was generally only made in small or "craft" quantities.  This process is believed to have been initially discovered by early Roman glass-makers.  The process however was lost and was not rediscovered until sometime in the 17th Century either by Johann Kuckel in Bohemia or by Antonio Neri in Florence, Italy (experts are uncertain as to who deserves the credit).  It was not however until the 1920s that the chemistry was understood and explained (by 1925 Nobel Laureate in Chemistry Richard Zsigmondy).  The legend that ruby or cranberry glass was first created when a nobleman tossed a gold coin into a vat of molten glass is just that ... a legend without basis in fact since the gold would have had to been first dissolved in Aqua Regia.  The height of ruby and cranberry glass production appears to have been during the Victorian era.

While the Leighton-Russell patent was intended to allow for increased production of opalescent glass at lower cost, producing opalescent glass, and especially cranberry opalescent glass was still a time-consuming and expensive process; thus cranberry opalescent glass lamps are quite hard to find.  Hulsebus, in the "Price Guide for Miniature Lamps", rates this cranberry opalescent finger lamp as being "rare".  Our data confirms that examples of this lamp are in fact hard to find; since June of 2002, we've only seen seven complete and undamaged examples of this lamp and four other which were missing their burners and chimney.   


Barry and Kay Schwartz are power sellers on ebay, under the seller name of kayschwartz. Kay and Barry are active members of the Night Light Club and The Historical Lighting Society of Canada.  They may be reached at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

 

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