The single colorless glass lamp font recovered from the wreck site is pressed in the ‘Circle and Ellipse’ pattern, with a hexagonal base and dates generically to 1840-1870. Its distinctive design is also seen on vases produced in the Eastern United States. Lamp fonts of this style were manufactured by the Boston & Sandwich Glass Company and by the McKee and Brother Glass Works of Pittsburgh, Pennsylvania. The latter featured the lamp in its 1859-60 catalog, which stated that a dozen could be purchased with a whale oil burner for $4.00 and with a fluid burner at $4.66 per dozen. A number of other companies specialized in similar patterned glass lamps.
The advent of the pressing machine in the late 1820s revolutionized the manufacture of glassware and facilitated the production of vast quantities of pressed glass in hundreds of different patterns. While mold-blown glass necessitated the muscle and lung technique of glass blowers, pressed glass on the contrary, was molten glass mechanically pressed into a mold by a metal plunger affixed to a long lever-like handle. This new technique permitted the mass production of glassware, lowered manufacturing costs and consequently retail prices. Now that thousands of identical items could be readily produced, glassware was no longer a luxury for the wealthy, but rather a commodity that could be afforded by all. Naturally, demand soared for affordable items including household lamps.
By the 1840s, companies such as the Boston & Sandwich Glass Company realized that in order to remain competitive, they needed to introduce major style changes in their products. They invested heavily in the purchase of molds to make glass fonts with the knowledge that it required far less time to teach a glassworker how much glass to drop into a pressing mold than it did to train a glassblower to make free-blown fonts or to blow the correct size bubble into a patterned mold.
Pressing glass had in fact entirely transformed the glass industry from one that relied almost exclusively on artisans to one that was augmented by molds. Deming Jarves, founder of the Boston & Sandwich Glass Company, estimated that by the mid-1850s glass companies were spending more than two million dollars on pressing machinery and molds alone.
The Jacksonville ‘Blue China" wreck lamp font does not appear to be a companion to either of the glass lamp globes recovered from the site because the opening at the bottom of the gl:bes are too large to fit the smaller lamp stem. The lamp font and base appear to have been pressed in a multi-part metal mold of either brass or iron. Such lamps produced at the Boston & Sandwich Glass Company were pressed in two-part molds. The pressed circle and ellipse patterned font was attached to the pressed base using a wafer construction, whereby a circular glass wafer or merese inserted in between the two pieces interconnected them while the glass was still extremely hot.
The lamp font was seemingly produced by this same process. However, if it was pressed in one piece then it could have been manufactured by the New England Glass Company of Massachusetts. The American Flint Glass Company of South Boston, Massachusetts, also manufactured such mold-blown lamps.
The Jacksonville “Blue China” lamp font – one of two on the wreck – is likely to have been part of a small cargo because a shipboard lamp would have been gimbaled and rigidly mounted. The recovery of two other non-related glass lamp globes suggests that the ship was in fact carrying a minor consignment of lamp parts. Lamp components were frequently produced separately, their varied glass and brass pieces often derived from different manufacturers and later assembled by employees of the lamp industry.