During the second quarter of the nineteenth century American glass factories reached a golden age in the production of fine free blown, molded, cut, and engraved flint (lead) glass. Prior to this time the domestic glass industry suffered from competition with England and the Continent. Tariffs levied on imported glass in 1818 and again in 1824, however, served to stimulate American glass production and the number of glass factories increased dramatically. Boston, New York, Philadelphia, Baltimore, Wheeling (West Virginia), and Pittsburgh became important production centers for fine tableware. The blown flint glass of this period attests to the skill and ingenuity of American glass craftsmen who were intent on matching the quality of imported wares while meeting the demands of the expanding middle-class market.

One can still purchase outstanding examples of early- to mid-nineteenth century blown flint glass worthy of inclusion in any collection of American decorative arts. While the first rule is to buy what you like, a wise buyer should also approach objects with a critical eye. Early American glass manufacturers rarely marked their wares, and continued use of traditional production techniques allows for fakes and reproductions to be made quite easily. What follows are guidelines in assessing the authenticity and aesthetic merit of blown glass. Armed with knowledge of glass history and technology, and knowing how to apply these connoisseurship skills, it is possible to demystify the process of buying early American glass.1

Fig. 1: Blown molded “Curtain” pattern pitcher with applied tooled handle, East Cambridge, Mass., New England Glass Company, ca.1850–1870. Lead glass. H. 7-3/4 in. Courtesy of M. Finkel & Daughter.

Attribution: In addition to the fact that few pieces of early glass are marked, the problem of identifying a place of manufacture and maker is confounded by the general lack of specific production documentation for individual factories. The mid-century blown molded “Curtain” pattern pitcher shown in figure 1—called a jug during the period—has enhanced value because it is illustrated in an 1868–1869 New England Glass Company catalogue.2

Attributions are often made by piecing together bits of information including archaeological evidence from factory sites, history of ownership in a glassworker’s family, period invoices, newspaper advertisements, personal correspondence, or by matching the object with others having a firm attribution. Having a definitive attribution adds to the significance and value of a piece, but the words “possibly” or “probably” used in the context of attribution should not discourage the buyer.

Provenance:A documented provenance—ownership in an important family, part of a major collection or descent in a glassmaking family—can greatly add to the desirability of an object.  Be wary of “extremely rare” objects that come on the market with an unknown or questionable history.

Material: Although there are thousands of recipes for making glass, the three basic ingredients remain the same: silica (sand), an alkali flux (potash or soda) to lower the melting point, and a stabilizer (lime or lead) to resist moisture. Determining whether or not the glass contains lead is an important aid in establishing the country of origin and can also be helpful in authenticating an object.

In the search for a fine quality glass, in the 1670s the English developed a recipe using lead oxide that became the standard for English glass tableware from that time forth. Lead glass has significant weight, is resonant, and has a high refractive index that gives it extraordinary brilliance when cut.

By the beginning of the nineteenth century, American glasshouses were producing lead glass tableware in “flint” glasshouses and nonlead glass in the window and bottle factories, which occasionally produced hollowware as well. Glass factories in Germany and Bohemia, however, used a potash-lime (nonlead) recipe. Great quantities of glass from both England and the Continent were imported in the eighteenth and early nineteenth centuries and it is not uncommon to find similar forms from both regions.3

Determining whether glass contains lead is thus significant in establishing attribution, though it is not always obvious. In general, lead glass weighs more than nonlead, however, the thickness of the glass will also affect the weight. Although there is much debate about the effectiveness of using a black light to determine lead content, this technique is commonly practiced. Generally under short-wave ultraviolet light, colorless lead glass will fluoresce a light icy blue.4

Color: Glass manufacturers made colorless glass by adding manganese dioxide, known as the “glassmaker’s soap,” to the batch.5 Colorless glass may actually range from blue-gray to pinkish-tan depending upon the balance of ingredients in the specific batch. Colorless glass from the period is not as “white” or pure as today’s colorless glass.

Colored glass became very popular toward the middle of the nineteenth century, and some colored glass commands high prices among collectors today. Knowledge of which colors in which forms are rare is key to making smart purchases; unfortunately, the topic is too involved for discussion here.

Production Technique:Glassblowing—taking a gather of molten glass on the end of a hollow pipe and inflating it with one’s breath—is an ancient technique that dates back over two thousand years. Until the second quarter of the nineteenth century glass vessels made in America were either “free blown” or blown into a mold that gave them their shape, decoration, or both. During the late 1820s American glass factories began to produce wares using a mechanical press; this was the first significant development in the history of glassmaking since the invention of the blowpipe.6

Fig. 2: Free blown compote with folded rim, baluster stem, and applied foot; free blown pitcher with applied handle, United States, ca.1815–1840. Lead glass. Pitcher: H. 8-1/4 in. Courtesy of M. Finkel & Daughter.

The compote and pitcher in figure 2 are wonderful examples of “plain” (undecorated) free-blown glass. In free-blown glass, expect to see striations caused by rotating the object on the blowpipe. When the object is being formed, it is transferred from the hollow blowpipe to a solid pontil rod (also called a punty) so the neck and rim can be finished and handles added. The rough pontil mark is obvious on the bottom of the pitcher. Often blown objects will have a slightly indented base or “kick” in the bottom to keep the rough pontil mark from scratching other surfaces. The pontil can also be ground or polished smooth.7

Fig. 3: Pair of blown three-mold decanters (McKearin GI-27 with GI-8 stoppers), United States, 1815–1835. Lead glass. H. (with stoppers) 10-3/4 in.; 10-1/2 in. Courtesy of M. Finkel & Daughter. Photography by Luigi Pellettieri.

Fig. 4: Blown molded bowl, United States, probably Philadelphia area, 1920–1930. Amethyst lead glass. H. 2-5/8 in. This is one of the “Mutzer group” of fakes that came on the market in the 1940s. Courtesy of Winterthur Museum, Del. (59.3111).

The term “blown three-mold” (Fig. 3) is used to describe both a technique and a style of glass, primarily tableware, made roughly about 1815 and 1845. In this process, glass was blown into a full-size mold that gave an object both its form and pattern.8 Because it is blown, the glass follows the contour of the mold, resulting in the pattern being felt on both the inside and outside of the object.9 Blown three-mold glass often has thin walls and may weigh less than blown and cut pieces of about the same size.

Form: Learning when certain forms were introduced, whether they had parts such as lids or stoppers, and the subtleties of proportion, can aid in identifying if a form is appropriate to the date assigned. Common blown glass forms made prior to 1850 include decanters, celeries,10 compotes, pitchers, wine glasses, straight sided tumblers, sugar bowls, creamers, flasks, bar bottles, oil lamps, candlesticks, and cruet bottles.11 A form with no logical reason for its unique characteristics is probably a fake. The blown three-mold bowl in figure 4 came on the market in the 1940s and appealed to collectors because of its unusual shape; comparison with period examples determined it was a fake.12

Function: Objects should serve their intended function. For example, is the handle on a pitcher or creamer sturdy and soundly attached to the body so that it could be used? It is not uncommon to find fake or reproduction pitchers or creamers with perfunctory handles lacking the robust craftsmanship seen on authentic period objects. Notice that all the pitchers illustrated here have handles that begin with a strong attachment well below the rim, and finish with a firm connection at the side, as should all handles on flint glass of this period. Similar objects, where the lower part of the handle was attached to the body first, date from the late 1860s or thereafter.13

Ornament: Glass may be decorated while it is being formed at the furnace, or using various techniques after the object has annealed (slowly cooled). Hot decorating techniques include adding metallic oxides to the batch to change the color, using molds to create a pattern on the glass, superimposing one layer of glass (sometimes of another color) over the original gather of glass, using tools to manipulate the glass, and encasing a coin or sulphide in the object. Simple, traditional techniques such as trailing (winding thin threads of glass around part of the object) and tooling (crimping, pincering or otherwise manipulating the glass using traditional glassmaking tools) (see Fig. 1), best compliment the forms of this period.

Fig. 5: Blown and engraved footed bowl, Pittsburgh, Penn., Bakewell & Company, ca. 1815–1840. H. 7-3/8 in. Courtesy of Corning Museum of Glass (94.4.9).

Cold decorating techniques utilized during the first half of the nineteenth century include copper-wheel engraving and cutting.14 Copper-wheel engraving is used to create images or “write” on glass (Fig. 5). The engraver holds the object under a small rotating copper wheel and abrades the surface, resulting in a grayish matte design composed of fine lines. Be aware that engraving is sometimes added to period objects to enhance their value.

For cut glass, the pattern is marked on the glass blank, then cut, smoothed, and polished. Most of the glass cutters working in America during this time were trained in glasshouses in England and Ireland, so Anglo-Irish designs such as the strawberry-diamond and fan motif are typical for the period (Fig. 6). In many instances combinations of these motifs exhibit a creative, experimental spirit that is seen only on American glass.

Fig. 6: Blown and cut celery, decanter, and compote, United States, probably Pittsburgh, 1825–1840. Lead glass. Decanter: H. (with stopper) 11-3/4 in.; compote H. 7-3/8 in., D. 10-3/4 in. Courtesy of M. Finkel & Daughter.

Style: As with all decorative arts, glassware reflects artistic movements. Favored early nineteenth-century motifs included neoclassical swags, festoons, and tassels, classical dolphins, gothic arches, and simple graphic patterns. By 1840, the busy designs of the 1820s and 1830s were replaced by simple, smooth surfaces—broad flutes or panels. This shift in style started much earlier in Britain, first as a more affordable alternative to the fancier patterns, and gradually as a matter of preference.15 Scholars generally attribute the change in fashion in America to the depression of 1837, which stimulated a need for cheaper consumer goods, and of course the simple cutting and plain molds were much less expensive to produce. In this instance, economics and fashion went hand in hand.

As this shift in style was occurring, a technique developed for creating a heavy molded glass that resembled cut glass (Fig. 7).16 The large protruding pillars, or ribs, accentuated the optical quality of the glass without the expensive time and skill required for hand cutting. While some pillar molded forms, such as pitchers, are quite easy to find, others, like large punch bowls, are more rare. The thick, bold forms and lustrous smooth surfaces make pillar molded glass particularly appealing to today’s market.

Fig. 7: Pillar molded celeries, compote, and punch bowl, United States, probably Pittsburgh, 1840–1860. Lead glass. Punch bowl: H. 10 in., D. 12-1/2 in. Courtesy of M. Finkel & Daughter.

Condition: As with all antiques, condition is paramount in determining value, though when an object is rare, condition may be less significant. Chips to rims17 and bases (feet), cracks (particularly where a handle attaches to the body) and broken finials are not unusual in objects that have been used extensively.18 Make sure that wear (scratches and bruises) occurs in the correct places—where the object rubbed against the table, where the lid touched the rim, where someone’s ring repeatedly hit the bowl of a goblet.

Repairs are often difficult to detect, so objects should be examined carefully. Chips may have been smoothed out of a rim, or an entire foot may have been ground to a smaller diameter. If an object looks out of proportion, it might have been altered. For example, a broken celery, originally tall and elegant, may have been transformed into a bowl; or the badly chipped edge of a wine glass may have been ground down. Clues to such a history may lie in an ornamental engraved band or other decoration appearing incomplete or too close to a rim.

Overall Appearance: While all the points of connoisseurship are necessary to evaluate an object for authenticity, its overall appearance—the combination of form, balance, style, color, decoration, quality of craftsmanship, and condition—is what makes it immediately attractive and ultimately worthy of purchase.

To gain an understanding of glass it is important to handle and examine as many objects as possible, confer with specialists, and consult the most recent publications by recognized experts in the field. Applying the methods of connoisseurship outlined above to the learning experience will further refine one’s skills of assessment.    

Mary Cheek Mills is Gallery Director at M. Finkel & Daughter in Philadelphia. She regularly lectures and conducts workshops on glass at the Cooper-Hewitt National Design Museum, The Smithsonian Associates, Sotheby’s Institute of Arts, Winterthur Museum, and other institutions.