Early Steps in the Evolution of American Pressed Glass
The late Kenneth M. Wilson, former Curator of American Glass at the Corning Museum of Glass and past Vice President of NBMOG, spent decades studying the development of American glass pressing technology. This development is thought by many to represent the country's most important contribution to the world history of glass. In 1972 Wilson addressed the subject in his book New England Glass & Glassmaking (Strubridge, MA: Old Sturbridge Village). Two years later he expanded his observations for the article "American Contributions to the Development of Pressed Glass" published in Technological Innovation and the Decorative Arts (Charlottesville: The University Press of Virginia, 1974, pp. 167-206).
Wilson pays special attention in his article to a relatively primitive form of pressed glass described by collectors as the "lemon-squeezer" foot (see illustration to left). This foot design was quickly and easily shaped in a metal mold, which entailed less expense for the manufacturer than traditional free-hand shaping techniques. The design features a ribbed concavity in the underside, which, in addition to being ornamental, was preferable to a solid pressed foot because it requiring less glass to make, was less likely to crack during cooling, was less likely to rock when standing, and resulted in a more efficient transfer of force through the glass during the pressing operation. After the foot was removed from the mold it was joined while still hot to the upper parts of the article being produced. These parts, whether for lamps, candlesticks, compotes, wine glasses, salt dishes or other tableware forms, were generally larger or more complex in shape than the feet and still had to be made using the traditional and more costly process of glassblowing.
Examples of lemon-squeezer feet are represented in Continental, English and Irish glass dating back to about 1780. They are among the earliest examples of a trend seen in 18th-century glass production toward increased mechanization, a trend experienced by many trades of the period. This movement toward mechanized production is recognized as one of the hallmarks of the Industrial Revolution, a cultural phenomenon that profoundly transformed the character of Western civilization. Its effects were expressed in the emerging national character of the United States, where "Yankee ingenuity" and technological progress were celebrated with almost religious fervor. It is not surprising, therefore, that the early step toward mechanization represented by the lemon-squeezer foot was adopted by manufacturers in America, or that it led to a dramatic leap forward with the invention of the American fixed-fulcrum glass press in the 1820s (see illustration below).
Lamps (left & center left) South Boston Flint Glass Works or Phoenix Glass Works So. Boston, MA; 1813-1830 H: 7 3/4" & 10 1/2" NBMOG Collection Gift: Alice Wilson Acc. 2008.010 & 2008.011
Lamps (center right & right) Pairpoint Glass Works Sagamore, MA; 1989 H: 10 1/4" & 7 5/8" NBMOG Collection Gift: Alice Wilson Acc. 2008.010 & 2008.011
Plunging Die with Wood Handle Possibly from the Mt. Washington Glass Works or Pairpoint Corp. and successor firms, South Boston & New Bedford, MA (1837-1957); the rosette design might relate to lamps described as "rose foot" in 1828 correspondence of the Boston & Sandwich Glass Company of Sandwich, MA; L: 10"; NBMOG Collection, gift: Kirk J. Nelson; acc. 1998.084
Recreated pattern for a foot mold to be used with a hand-held plunging die Kenneth M. Wilson Punta Gorda, FL; 1989 H: 3 1/2" x W: 8" x L: 8" NBMOG Collection Gift: Alice Wilson Acc. 2008.015
Lemon-Squeezer Foot Underside of the Cains lamp shown in the group illustration above, 2nd from left; the embossed base concavity features a design of 27 serrated ribs
"Mercurial Ring" Decoration Tooled air-trap of the Cains lamp shown in the group illustration above, extreme left. Collectors describe this decorative feature as a "mercurial ring" because reflecting light creates the misleading impression that the ring holds mercury. Wilson illustrates this lamp (from his personal collection) in New England Glass & Glassmaking, p. 228.
"Chain" Decoration Applied and tooled decoration ornamenting the Cains lamp shown in the group illustration above, 2nd from left
"American Pressed Glass" Illustration from English glassmaker and author Apsley Pellatt's Curiosities of Glass Making (London: David Bogue, 1849, p. 121). In 1831 Pallett patented a similar machine for pressing glass "by the mode lately introduced from America." NBMOG Rockwell Library Collection, acc. #L2009.001
"Drop Pinching" Illustration of the hand-held, pliers-like tool used for pressing glass chandelier drops, from Apsley Pellatt's Curiosities of Glass Making, p. 123 (1849 first edition, NBMOG Rockwell Library Collection, acc. #L2009.001).
At the time Wilson published his article for Technological Innovation in the Decorative Arts he believed that lemon-squeezer bases were formed with a variation of the pliers-like tool used to make chandelier drops (see illustration to left). Wilson speculated that several steps occurred between the use of this tool and the invention of what he referred to as the "American machine press." Unfortunately, the burning of the U.S. Patent Office in 1836 destroyed much of the written record documenting this development. Undaunted, Wilson continued to pursue his research. His efforts were rewarded more than ten years later when, rummaging through the storage shelves of the Pairpoint glass factory in Sagamore, MA, he made an extraordinary discovery. He came across an old glassmaking tool that appeared to be a handled plunging die (see illustration below). Wilson immediately associated the rosette design on the die with the embossed underside of the "lemon-squeezer" style lamp base. Examining the tool, Wilson considered the surprising possibility that lemon-squeezer style bases were made with a hand-held plunging die rather than a pliers-like tool. If so, this would represent an important and previously unrecognized step in the sequence that led to more sophisticated pressing technology.
To test his idea Wilson constructed a plaster model or "pattern" of a mold that could be used with the hand-held plunging die (see illustration to left). In the 19th century glass manufacturers made plaster patterns like this as a required step in the creation of metal molds. Wilson, on the other hand, appears to have used his plaster pattern to actually shape hot glass. Under his direction workers at the Pairpoint factory gathered glass from a melting pot and dripped it into the plaster mold. Wilson then forced the hand-held plunging die into the glass, shaping the base and embossing the rosette design. His experiment proved successful. Careful examination of the foot of the amber lamp shown above indicates that it was formed directly in Wilson's plaster pattern. During the course of experimentation the plaster was damaged by the corrosive hot glass, so Wilson made a more durable graphite mold that differs slightly in detail from the plaster model. Those slight differences are found in the foot of a second lamp made for Wilson at Pairpoint (see group illustration above, center right). Wilson illustrates the graphite mold and the Pairpoint plunging die in his book American Glass 1760-1930(Toledo, OH: The Toledo Museum of Art, 1994, p. 267), and briefly discusses the new theory. His experiments prove conclusively that it is possible to press lemon-squeezer style feet with a hand-held die.
Wilson's idea is exciting but far from fully explored. He does not mention, for example, that the rosette-patterned plunging die he found at Pairpoint can be unscrewed from its wood handle and mounted on a machine press. Neither does he mention that the handle almost certainly is not original to the die. It appears to be the same handle design used to open and close machine-press molds. These handles were meant to be interchangeable, so that a single pair could service a large number of molds. Could it be that a handle was simply unscrewed from a machine-press mold and screwed onto the rosette-patterned die? If so, this in no way invalidates Wilson's theory that the earliest such dies were hand-held. It just means that this particular die probably does not date to the earliest period. It also raises two important questions: were hand-held dies replaced by machine-mounted dies in the production of lemon-squeezer style bases, and, if so, at what point did this occur?
Careful examination of the glass bases could supply evidence relating to this and other technological developments. Notice, for example, that the height of a glass base pressed in Wilson's mold would vary with the amount of glass put into the mold. In 1830 a mold component called a cap ring was developed to predetermine the height of pressed glass mugs. Was a similar component developed for lemon-squeezer style base molds, and could examination of the glass bases show which examples preceded this development and which followed it?
Similarly, at what point might lemon-squeezer style bases have been made with molds featuring hinged sections? Wilson's mold is not hinged, so bases pressed in it would have to be removed either by dumping them out or by picking them up with an iron rod on which a small bit of hot glass had been gathered. Wilson does not explore this question, but he does footnote a fascinating reference to the use of hinged molds. In 1828 New England Glass Company superintendent Thomas Leighton wrote to John Ford at the Midlothian Glass Works, Edinburgh, about "a few of our Moulded Artikles [made] the same as you Make the Square Feet. The Mould Lifts with 2 ha[n]dles and opens at the corners" (quoted from Jane Shadel Spillman, "The Leighton-Ford Correspondence," Acorn: Journal of the Sandwich Glass Museum, vol. 3, 1992, pp. 3-6).
Wilson apparently recognized the likelihood that the tool he discovered at Pairpoint was made many years after the earliest production in America of lemon-squeezer style bases. In his text he states that "the hand press and open mold continued to be used until about 1840...." His photo caption, however, dates this particular die as "probably late nineteenth-early twentieth century" (American Glass 1760-1930, p. 267). Did he think the die was made for the production of Colonial Revival items? It might be possible to confirm or modify Wilson's date range for the die by looking for glass feet made using the die. As we would expect, the die fits perfectly into the base concavities of the test lamps made by Wilson at Pairpoint. It would represent an exciting discovery if we could locate an antique or Colonial Revival item into which the die also fits. In the mean time, one fact at least is apparent: the test feet produced by Wilson at Pairpoint are far too small for the tall, elaborately ornamented style of lamp he chose to duplicate.
There is no mystery, however, concerning the reason for Wilson's choice. By far the most technically impressive, decoratively embellished, historically documented and highly esteemed American lamps featuring lemon-squeezer bases are those attributed to South Boston glassmaker Thomas Cains (b. 1779, d. 1865). Wilson illustrates these lamps extensively in all his publications on the subject of early pressing. It is not surprising that he attempted to replicate them through his experiments at Pairpoint.
In 1812 Cains immigrated to South Boston from the Phoenix Glass Works in Bristol, England to work at the new window glass factory of the Boston Glass Manufactory. Finding the works largely inactive due to the effects of the British blockade, Cains persuaded the owners to let him set up a small six-pot furnace for the production of tableware and other articles in flint glass. This was the first furnace of its kind in New England. For this reason Cains is celebrated as the father of the New England flint glass industry. About 1820 Cains established his own factory in South Boston, which he named the Phoenix Glass Works after his former workplace in England. The factory continued operation until about 1870.
Cains undoubtedly was familiar with the production of lemon-squeezer style bases from his early glassworking career in England. He might even have been the first to manufacture this type of glass in America. While it is possible that one or more of his American competitors preceded him for the honor, their glass cannot be identified today with sufficient certainty to prove it. Glass attributed to Cains, on the other hand, includes an impressive group of lamps featuring lemon-squeezer bases. These lamps are attributed to Cains on the basis of several distinctive decorative treatments that ornament their blown fonts and standards.
One of these decorative treatments, referred to by collectors as the "mercurial ring," consists of a ring of trapped air formed in the side of the article during the tooling of the hot glass. Three of the lamps shown above feature mercurial ring decoration in their blown fonts. A second decorative treatment is described as chain decoration. It was made by applying two parallel threads of glass to the exterior of the article and then pinching them together at regular intervals. The South Boston lamp shown above, center left, and its reproduction, center right, both feature chain decoration around their blown standards. Today examples with mercurial ring and chain decoration are highly prized by collectors. They also make it possible, as noted above, to associate Thomas Cains with the production of lemon-squeezer style bases.
Wilson declares in American Glass 1760-1930 that "machine pressing of glass, invented in the United States in either 1825 or 1826, was the most important technological advance in glassmaking since the discovery of glassblowing and the blowpipe in ancient Roman times." NBMOG is therefore delighted to receive as a recent gift the lamps and research tools that document Mr. Wilson's exploration of this pivotal moment in glassmaking history.
Plunging die unscrewed from its wood handle; acc. 1998.084
Illustration showing that the wood handle from the rosette-pattern plunging die can be attached to the threaded handle posts used to open a machine-press mold
