with its depth and translucency, owes its intrinsic qualities to metallic oxides, such as cobalt, giving fine blues, silver, pale and deep yellows, pink from iron and antimony, and ruby from gold and copper, which also yields fine greens. When these oxides are mixed with the glass, in its fused state, it is termed pot metal, but if the coloured oxides are applied to the surface of the glass only, it is termed flashed or cased glass. Ruby, owing to its depth of colour, is usually cased glass. Fine blues are often flashed, and splendid effects are produced by flashing ruby over yellow, or blue pot metal glass. Cased glass is of the greatest value owing to the variety of tint that can be produced on a single sheet of glass, and also that the colour may be removed by grinding or by the use of fluoric acid.

The rationale of the glass painter is—1st, The scheme of composition and colour shown on a small scale. 2nd, A full sized cartoon in charcoal or monochrome, with all the details carefully drawn, and showing the lead lines and positions of the iron stanchions for strengthening the window. 3rd, A tracing on cloth showing the lead lines only, called the cut line, on which is cut the selected pieces of glass. 4th, Tracing all details from the cartoon, with brown enamel on each piece of glass, the pieces after firing being then fixed in the leading, and kept together with H shaped leads. A diagram is given here showing the leading of an example of 13th century glass.

The brown enamel, which is used entirely for outline, detail or shading, is a fusible glass in combination with opaque manganic or ferric oxide, and tar oil. With this enamel, smear shading or stipple shading is worked. This may be removed as required, before firing, by means of a pointed stick or quill, so as to give the details of embroidery, or of heraldic forms.

Silver stain (oxide of silver) introduced at the beginning of the 14th century is largely used in stained glass, and usually on the back thereof. According to the different degrees of heat in the firing, a pale yellow or deep orange of great transparency is produced.

Coloured glass was made by the Egyptians 4000 years ago, but the earliest stained glass windows recorded, were those of Brionde A.D. 525. None however are known to be in existence prior to those of St. Denis A.D. 1108. Other examples are found in Norman windows, with small medallions of figures and ornament of a decided Byzantine type, extremely deep in colour, being, by its style of treatment, termed mosaic glass. The 13th century, or early Gothic period, has single lancet lights, with medallions containing small figures surrounded by the typical 13th century foliage; or the windows were entirely of ornament in grisaille, arranged symmetrically, having narrow bands of ruby or blue, with wide borders. These grisaille windows are of a greenish white glass, with the ornament in outline, and the ground hatched with brown enamel in fine cross lines (fig. 1-2). Image unavailable: 13TH CENTURY GLASS. CHARTRES CATHEDRAL.
13TH CENTURY GLASS. CHARTRES CATHEDRAL. The north transept window at York cathedral, called the five sisters, is typical of this grisaille glass. The finest examples however, are at Salisbury and Chartres cathedrals. Later in the period, single figures were introduced under a simple canopy or gabling, plain or crocketed, with an ordinary trefoil arch.

“Quarry glass,” square or diamond in shape, with brown enamel details, was frequently used, where simple masses were desired.

In the 14th century, the figures were larger and placed under canopies in each light of the mullioned windows, such figures in rich colours forming a bright belt across the window, surmounted by the canopies, cusped and crocketed, and in strong yellow pot metal, or yellow-cased glass. The borders were narrow, with a somewhat natural rendering of the rose, the maple and the oak.

In the 15th century, a further change took place, figures became more numerous and the canopy or shrine larger, and chiefly in white glass, with the crockets and finials tipped with yellow stain. The coloured border of the earlier glass is entirely absent, its place being taken by the shaft of the canopy, and the crockets, finials and ornaments are square in treatment and based chiefly on the vine leaf.

Fairford church, perhaps, contains the finest series of late Gothic glass A.D. 1500-30. Like the contemporary architecture of the 16th century, the Renascence now influenced stained glass. The canopy still survived, but was horizontal or pedimental in form, with purely classical columns and details. Good examples of this period are the windows of King’s College Chapel, Cambridge (1520), where rich Renascence work is introduced into late Gothic mullioned windows. About 1540, transparent enamels were introduced with skill and reticence, but gradually glass painters began to vie with pictorial oil painting in effects of light and shade, the ground work or material losing that beautiful translucent or transmitted colour, which is the chief glory of stained glass. An example showing the degradation of this art is the west window of New College, Oxford, painted by Jervas, 1777, from designs by Sir Joshua Reynolds.

The ornamentation of stained glass naturally followed contemporary architecture in the treatment of style, differentiated only by the technical necessities of material. For instance, in the early English glass (plate 31), the details of the ornament have the characteristic spiral arrangement and the trefoil foliage of contemporary architectural ornament, only the foliage is treated more in profile, as being more suited to the technical necessities of leading and brush work.

Most of the detail, however, shows a strong affinity to French contemporary ornament, this doubtless was owing to the influence of French craftsmanship and tradition in the stained glass of that period.

In the 14th century, the English craftsman attained a thorough mastery over his materials, and consequently the type of ornament followed English contemporary architecture more closely.

To sum up, stained glass changed through the different periods from the rich coloured mosaic of the Normans—the equally rich coloured medallions and grisaille glass of the early Gothic—the decorated Gothic, with glass in lighter colours, and a prevalence of yellow stain, culminating in the later Gothic period, when largeness of mass, lightness, and silvery colour, were the characteristics. A beautiful treatment of stained glass, dating from the 15th century was used by the Arabians; this glass, which has a singular gem-like quality, and without enamel or stain, was let into a framework of plaster, which had been cut and pierced with geometrical or floral patterns.

Modern stained glass has attained a high degree of perfection in design and material under Burne Jones, Walter Crane, Frederic Shields and Henry Holiday, with glass such as that produced by Morris, Powell and Sparrow, and the American opalescent glass of La Farge and Tiffany.

The individuality of their work, appropriateness of treatment, based upon the splendid tradition of the past, mark a distinct epoch in history of stained glass.

Splendid heraldic glass by A. W. Pugin may be seen in the Houses of Parliament, Westminster; and in the hall and staircase of the Rochdale Town Hall, there is a fine series of windows by Heaton, Butler, and Baine, remarkable for dignity of style and unity of conception.