For Gosling, the attraction of using glass is its clarity and transparency, which gives an impression of light and air. The mirror’s reflective qualities have long been used to amplify the natural and artificial light available in interiors and increase the sense of space. In furniture making in particular, glass is often used in the form of mirror-glass or as a purely decorative, illusionistic element in cabinets and writing desks.
William Orpen, The Signing of Piece in the Hall of Mirrors, Versailles, 28 June 1919, 1919. The Imperial War Museum, London
Mirrored surfaces have been used since the Stone Age; the earliest examples were made from highly polished volcanic glass, such as Obsidian. Evidence has been found in Anatolia (modern-day Turkey) of polished stone mirrors dating from 6000 BCE, while Bronze and Copper mirrors dating from between 4000 and 2000 BCE have been found in Mesopotamia, Egypt and China.
Solid, polished metal mirrors, however, were too expensive for widespread use, and their low reflectivity (the reason antique mirrors give a darker reflection than their modern counterparts) made them unsuitable for indoor use, as the artificial lighting of the time was limited to candles and lanterns. The more efficient method of coating glass to create mirrored surfaces has long been used: metalcoated glass dates from about the first century CE, while mirrors backed with gold leaf are mentioned in Roman literature around the same time. The Romans also invented a type of primitive mirror by coating glass with molten lead.
The first manufactured glass, made using sodium carbonate, or soda ash, extracted from vegetation ash, was probably Phoenician; but small glass jars, bottles and beads, including coloured glass created by the addition of different minerals, have been found in Egypt dating from 2000–1500 BCE. There is also evidence that the Egyptians used translucent but very thick window glass from around the first century CE.
The art of glassmaking spread throughout Europe during the time of the Roman Empire, with techniques developing and becoming increasingly sophisticated. This resulted in examples of highly ornate glass designs and the evolution of glass enameling and gilding. An important innovation in glass manufacture occurred in Northern Europe in the eleventh century, with the discovery of how to make glass using potash (potassium carbonate) from the more readily available wood ashes. This formed an important distinction between Northern European glass and that which was made in the South or Mediterranean regions where soda ash was still used.
The island of Murano – to which the glassmakers’ foundries had been relocated by the Venetian Republic in 1291 due to the risk of fire to the city’s wooden buildings – had become an extremely important glassmaking centre by the fourteenth century. The Venetian glassmakers had a natural advantage in the abundance of nearly pure silica in the quartz pebbles (cogoli) that gathered on the riverbeds of the Ticino and the Adige; and a business advantage in having the sole trade monopoly for the Levant soda ash they used to mix it with. This gave the Venetians superiority over glass producers elsewhere, and Murano glassmakers retained their dominance in glass manufacture for centuries. They developed and refined new, sophisticated techniques in producing luxury materials, such as crystalline glass (cristallo); enamelled glass (smalto); glass with golden threads shot through (aventurine); milk glass (lattimo); and the famous multi-coloured glass or millefiori.
Pier glasses, consoles tables and candelabra in the Saloon of Holkham Hall, Norfolk.
By the sixteenth century, Venice was also a major centre of mirror manufacture, having invented a way to make mirrors out of ordinary plate glass by coating the back of it with a tin–mercury amalgam, thus producing a near perfect reflection and image. Glass mirrors from this period – whether from Venice, the Saint Gobain factory in France, or Bohemia – remained extremely expensive luxury items. Since thin glass is a distinctive characteristic of antique mirrors one way to tell if a mirror is in fact an antique is to hold a coin up to the mirror surface: the closer the reflection is to the coin, the thinner the glass.
Mirror glass in furnishings became popular during the seventeenth century, but the prohibitive cost and difficulty of manufacturing large pieces of mirror restricted both its use in interior design and the possibilities of largescale application. Mirrors in lavish frames were, however, used as decoration in palaces and courts throughout Europe, with the spectacular Hall of Mirrors at Versailles being a notable example and an outstanding technical achievement for its time.
Methods invented by the French glass workshops in the 1700s facilitated fairly largescale production of mirrors, which led to their relative affordability and prevalence in eighteenth-century interiors. The popularity and wide distribution of mirror glass was stimulated by the need for an increased amount of artificial light. During the sixteenth and seventeenth centuries, this need had been satisfied by placing candles in front of highly polished concave metal plates. But by using silvered mirror glass, the light effect was multiplied. Large, silvered wall mirrors, hung over console tables and often placed against pier walls, became a commonplace and functional element, further illuminating interiors lit by artificial light.
Glass and mirrors continue to play an important role in furniture and interior design, although technology has moved on and allows a greater scope and variety of materials – most notably with the invention and subsequent commercial production of acrylic glass in the 1930s. This transparent man-made substrate can be used in place of glass and is on occasion preferable due to the ease of manufacture and low cost.