Louise’s Papers: Mirrors
by Louise Devenish

“Mirror, mirror, on the wall, which one is the fairest of them all?”

Glass itself is older than man, as old as the Earth — formed from masses of silica fused with intense heat by volcanic action. The first glass was probably in the form of a glaze a mixture of sand and minerals, fused onto the surface of stone or ceramics.

The use of mirrors both as household decoration and objects for personal use goes back to ancient times. The Egyptians, Greeks and Romans had small hand mirrors made of polished copper, bronze, silver and tin. Often the backs and handles of these mirrors were engraved and decorated with inscriptions and symbols — and some, even more elaborate, were backed in precious ivory and inlaid with jewels. Hand mirrors became an important part of every fashionable patrician lady’s toilette as were standing mirrors, which came into vogue shortly after in the First Century A.D. In his writings of this time, Pliny tells us of mirrors backed in zinc and we have seen frescos of cupids holding mirrors for beautiful ladies.

In the Middle East, mirrors were made out of rock crystal and were backed by a sheet of silver. Enameled and gilded glass was produced in ancient Syria and Egypt. No matter where mirrors were found in the ancient world, the one ubiquitous thing about them was their being in the possession of the wealthy.

Venice was the first city to revive the art of fine glassmaking during the early Renaissance period of the 12th and 13th centuries. It enjoyed a virtual monopoly on the manufacturing of glassmaking and was so protective of it that they moved its production to the island of Murano, where the glass artisans were forbidden to leave, thereby keeping the secret of glassmaking within the tiny isle. Death was the penalty for any glass craftsman caught trying to escape from Murano, but a few of them did flee to eventually sell the closely guarded secret.

Venetian glaziers employed the flat mirror technique, which involved using a blow pipe, a hollow iron tube four to five feet long. The artisan made a “gather” by dipping one end into the molten glass and then blowing through the other to make a bubble that he could manipulate and create into a sausage or cylinder shape, which was then cut off, flattened out and stretched. Next, the blown glass was taken to an annealing oven where the glass was smoothed out with an iron that resembled a scraper, and then rolled flat. The flattened panes were placed in an upright position and left to cool for as long as three days. After this, each plate, which had uneven edges, had to go through many more processes. The edges had to be ground down with finely powdered sandstone until they became smooth. Finally the glass had to be backed in order to give it reflective properties — creating a mirror.

The ovens could only accommodate a certain-size plate so that when large pieces of glass were desired, they had to be butted together, as we see in early Baroque mirrors, where the plate is generally in two pieces with the top slightly smaller and finely beveled and artistically engraved so to distract from the entire mirror being composed of two sections.

Glass-blowing was not always a successful venture: The glass had to remain hot and very often the “bubbles” would have to be returned to the furnace so the glass would retain its plasticity and the glass blower might have had to start all over again, hoping to produce a smooth final product. Another method was to just cut one end of the bubble and spin the blow pipe around on its own axis, making the bubble of glass open up in a flat disc or crown; this type of glass was used for windows. 

The basic composition of making glass is: 75 percent silica (which is usually sand, crushed white pebbles or white flint), 10 percent lime and 15 percent sodium or potassium oxide.

Burnt seaweed, or the ashes of marine plants and lime, were used for the “flux,” which was also called “salt.” Fuel to fire the ovens was primarily wood, but due to the rapid destruction of the woodlands in England a royal proclamation was enacted in 1615 that limited glassmakers to the use of coal to heat their ovens. Stone was needed to create the ovens, the blacksmiths would make the tools for glass blowing, and the carpenters the molds. It was a labor-intensive and costly process.

The Duke of Buckingham established the Vauxhall Glass Works in 1662. John Evelyn, the diarist, wrote, “Vauxhall glass is far larger and better than any that comes from Venice.” Vauxhall glass is frequently used to describe soft-colored, shallow-beveled, early-18th-century mirror plate.

In 1664, the Worshipful Company of Glass Sellers and Looking Glassmakers was incorporated in England. Mirrors were framed in exotic materials, rare woods, tortoiseshell, embossed silver and gilded frames. Imported lacquer panels were also incorporated into frames.

In 1702, the Bear Garden Glass House in London’s Southwark boasted of glass plates up to 90 inches high, which were “of lively color free from bladders, veins and foulness.” Glass houses took pride in smooth, clear panes, which brought in more money and could be used for the making of mirrors.

The French cast glass by pouring the molten material onto a flat iron surface with shallow sides. In 1687, Bernard Perrot perfected this particular casting process. This facilitated the production of mirrors in much larger sizes, which by the early 18th century could be set into boiserie (wood paneling) the full height of the room. The Manufacture Royale des Glaces was established in 1688. These glass works employed between 600-1,000 master glassmakers who polished and silvered the panes. The panes were placed on a large table where paper-thin sheets of tin were spread, making sure there were no creases or dents in them because the slightest imperfection would ruin the mirror. The tin was then generously spread with mercury, and once it had soaked in, the glass panes were placed on the top, where it stuck to the tin. Next, it was turned over and sheets of paper were placed over the tin-soaked mercury and pressed gently by hand to remove all the surplus mercury. It was then dried by a gentle fire or left out in the sun.

It was no wonder that this was such a well-paid job, as hardly anyone employed in this process lived long enough to enjoy the money they made — and if they did, they would certainly be crazy from the toxic fumes of the mercury. In 1857 François Petit-Jean replaced the lead backing on mirrors with a backing made of silver, which made the glass much clearer — and the glassmakers stayed sane and lived longer!

Glass for mirror plate continued to be an expensive commodity even with the introduction in 1773 of the British Cast Plate Manufacturers due to taxes that were levied on the raw materials used in glassmaking as well as on export duties on mirrors going out of England.

English law forbade factories of any kind in the Colonies; this law was to protect British industries whose products were highly taxed. Despite this law, Caspar Wistar, a German immigrant, opened a glassworks at Allowaytown, New Jersey, in 1739, marking the real beginning of glassmaking in the Colonies. With such factories as the Henry W. Stiegal Factory opening in Lancaster County, Pennsylvania, in 1765, mirrors still were largely imported from Europe until after the Revolutionary War.

In the 19th century, glass became thicker and not as attractive, hand-carved frames were replaced by composition frames (made from plaster reinforced with wire), and mirrors lost their exclusiveness.

During the early 20th century, many beautiful mirrors were made by hand, using exotic and unusual materials such as resin and lacquer. Today, these have become very valuable and are collectors’ items. It seems our narcissistic tendencies and love of reflecting our images in the light have always been with us and will remain forever.