In addition to the accurate and expressive drawing which goes to make good heraldry, the principal feature of glass design is obviously its colour effect, the grouping of the colour masses in such a way as will best express the subject in beautiful coloured light. In view of the obligatory nature of heraldic tinctures, though not of their exact quality, the harmony of colour may be helped by suitable treatment of the background (which is susceptible of variation that is only limited by the nature of the materials) in combination with the prescribed colours of the heraldry. And here occurs that temptation to alter the tinctures of mantlings which has proved too much for the correctness of some heraldic compositions. The design is usually made on a small scale, showing the colour scheme and the general composition, and a full-size drawing in black and white is then prepared, in which the arrangement of the leading and the character of other details are carefully indicated. On this the various coloured glass is laid and cut into the required shapes, which are then arranged in due order with the lead, and the whole is securely soldered together. The lead having a double groove is in section like the letter H, the inside surfaces being milled, to afford a better key for the glass and for the cement which is added for additional security. Pugin, whose influence on architecture was so impressive, had no less strong an effect on the heraldry which accompanies it so appropriately, and the beautiful armorial decoration of the Houses of Parliament, for which he is answerable, is a wonderful mass of fine work in glass and stone and other materials. No less remarkable in that it succeeded a long period of such extreme weakness, and was itself but the firstfruits of the revived interest in the subject. In this work Pugin was fortunate in the efficient assistance that was at his command, and the drawings by his son-in-law and pupil, John Powell, by Burgess and others, show how admirably the master mind was served. The drawings reproduced here were probably designed by Pugin, but the actual work is that of John Powell. However imbued with the mediaeval spirit Pugin was, the Renaissance feeling unmistakably asserts itself in these designs, and in spite of the Gothic detail of the tracery they seem to associate themselves naturally with the Tudor heraldry rather than with that of an earlier time. Indeed, it is possible that Pugin was not unmindful of this, for there is little doubt that he had studied the Renaissance work that is to be found, as well as that of the Middle Ages, in the neighbouring Abbey. [Illustration: FIG. 208.--Cartoon for Stained Glass. (Upper Part) Royal Gallery, Houses of Parliament.]