Page:Arts & Crafts Essays.djvu/126

 and at the same time joined to its neighbour by a thin grooved strip of lead which holds the two. "Coloured glass is obtained by a mixture of metallic oxides whilst in a state of fusion. This colouring pervades the substance of the glass and becomes incorporated with it." It is termed "pot-metal." An examination of such a piece of glass will show it to be full of varieties of a given colour, uneven in thickness, full of little air-bubbles and other accidents which cause the rays of light to play in and through it with endless variety of effect. It is the exact opposite to the clear sheet of ordinary window-glass.

To build up a decorative work (and such a form of expression may be found very appropriate in this craft) in coloured