Girandole is one name given to a free-hanging branched candleholder, but more commonly refers to a wall-hung looking-glass with one or more candle branches.
The light from a candle can be virtually doubled by reflecting it off a highly polished surface back into a room and although metal-backed glass was known in England during the Middle Ages, early sconces and girandoles employed plates of highly polished speculum to reflect the candle’s light. William Salmon describes several compositions of copper, tin, arsenic and nitre for casting “steel glaſſes” and methods of polishing same.
English glass-making in the sixteenth-, seventeenth- and eighteenth-centuries was frustrated by prestigious foreign imports, taxation and political intervention to the point where, on occasions, it virtually ceased.
The English glassmaking industry steadily prospered, producing large plates for looking-glasses, carriage windows etc. until Oliver Cromwell ordered ‘… an Excize of Twelve pence shall be laid upon every Twenty Shillings value of Glasse and Glasses of all sorts made within the Kingdom, to be paid by the Maker’.
Following the restoration of the Monarchy, a Royal Proclamation in 1664 forbade the imports of wrought glass plates in order to prop up English production. In the same year the Worshipful Company of Glass-sellers and Looking-glass Makers was incorporated, but their hegemony was confined to the city of London and an area extending seven miles round it.
In 1695 a duty of 20% was levied on looking-glass plates for a period of five years to top up the coffers for the war against France. A second act was passed in 1696 making the duty permanent which prompted much protestation and petitioning from the Glass-seller’s Company who claimed they had brought the art ‘to such perfection as to out-do the world’. Their persistence paid off, for the duty was halved in 1698 and abolished the following year.
There followed a tax-free period of almost half a century in which English glassmaking again flourished. Massive plates (by the standards of the times) were produced, allowing designers and specialist frame-makers to contrive large elaborate looking-glasses. However, the inevitable occurred and in the Excise Act of 1745 the then Chancellor of the Exchequer, Lord Pelham, levied a tax of 9s. 4d. per hundredweight (112 lbs. ~ 50.8kg) of ordinary (clear) glass.
Despite glass workers protesting the tax, it remained and many manufactories went under. The Dublin glass trade absorbed many out of work English glassworkers, and being a tax-free port (then, under English control), became a major exporter of looking-glasses to England and the Americas.
Purely as a matter of interest, I feel it is worth mentioning that in 1777 the tax on glass was doubled to raise revenue for the American Wars. In the same year, a duty was again imposed on imported glass to bolster the English glass trade.
English looking-glass plates in the late seventeenth and early eighteenth centuries were predominantly made by the broad sheet process viz. a large clump of molten glass was taken up on an iron blowpipe and blown into a bubble. Frequent re-heating was necessary to keep the glass fluid as the glass-blower continued inflating and spinning the elongated bubble. When the sausage-shaped bubble had attained the desired diameter and length, its ends were cut off with shears and the resultant cylinder was slit open lengthwise and laid flat on an iron plate. The glass was then annealed in an oven before being ground and polished to remove ripples and minor flaws.
Using the broad sheet process, relatively large plates could be produced. In 1700 the Duke of Buckingham’s glassworks at Vauxhall advertised plates of 72 ins. in length. Much larger (and often cheaper) French and Venetian cast plates were undoubtedly smuggled into England until she too took up the process of casting glass in the mid 1770s.
Diamond-cutting was the process of grinding a flat bevel or slightly convex reveal around the perimeter of the glass plate. It was ground and subsequently polished in the same manner as the faces of the plate. Eighteenth-century diamond-cutting, when present, was shallow – some being barely perceivable.
Silvering, or foiling
The reflective constituent of early looking-glasses comprised a thin mercury coating applied to the back of the glass. An amalgam with tin facilitated the mercury adhering to the glass which had to be scrupulously clean for the process to work.
Tin foil was rolled out on a polished marble or slate slab and gently smoothed with a wooden batten to eliminate any air bubbles. Mercury was then spread sparingly across the surface of the tin. The glass plate to be silvered was next lowered onto the mercury with a sliding action such that the greater proportion of mercury was driven out, leaving the thinnest film between glass and tin foil. Mercury, having a strong affinity for many metals, amalgamated with the tin, affixing itself to the glass.
Smaller plates could be more easily silvered by the following process:
The plates having been poliſ’d, are next to be foliated or ſilver’d, which is perform’d after the following manner:
A thin blotting paper is ſpread on a table, and ſprinkled with fine chalk; and then a fine lamina or leaf of tin, called foil, is laid over the paper ; upon this mercury is poured, which is equally to be diſtributed over the leaf with a hare’s foot or cotton. Over the leaf is laid a clean paper, and over that the glaſs plate.
The glaſs plate is preſs’d down with the right hand, and the paper is drawn gently out with the left ; which being done, the plate is covered with a thicker paper, and loaden with a greater weight, that the ſuperfluous mercury may be driven out, and the tin adhere more cloſely to the glaſs.
When it is dried, the weight is removed, and the looking-glaſs is complete. 
Thin spirit or oil varnish was sometimes applied to the back of the silvering to consolidate its somewhat granular surface.
Many looking-glasses ‘silvered’ in the manner described have now succumbed to the ravages of time: Damp environments can lead to the amalgam deteriorating as moisture corrodes the tin, resulting in conditions from dark staining through to complete loss of the silvering. Even in serious states of atrophy, period looking-glasses usually have much higher intrinsic value than if the plates are replaced.
Again, I feel it is worth mentioning that silvering mirrors with a solution containing actual silver didn’t come about until 1835.
Making the pair of girandoles
The pair of girandoles will be in close approximation to the example in fig. 5 below (less the carving and gilding on the inner frame). The moulding will be solely cross-grained walnut similar to that illustrated in fig. 4.
The components for the brass candle branches are currently being cast and my agents are scouring the locality for glass plates. Whether I will be fortunate to find a genuine mercury glass remains to be seen.
 William Salmon, Polygraphice, or, The Arts of Drawing, Engraving, Etching, Limning, Painting, Vernishing, Japaning, Gilding, &c., eighth edition,A. and J. Churchill, and John Nicholson, London, 1701, pp. 851-3.
 Geoffrey Wills, English Looking Glasses, Country Life, London, 1965, p. 43.
 Edwards, Ralph, The Shorter Dictionary of English Furniture from the Middle Ages to the Late Georgian Period, Country Life, 1983, p. 352.
 Ibid., p. 358.
 Wills, p. 46.
 Hinckley, F. Lewis, Queen Anne and Georgian Looking Glasses, Tauris Antiques Press, 1990, p. 9.
 Wills, p. 55
 John Barrow, Dictionarium Polygraphicum, C. Hitch and C. Davis, London, 1735.