The medallions are not, I think, all of one date, which is not surprising, for the filling of the windows of a big cathedral must always have taken many years. The difficulty of dating them is increased by the fact that much of the painting does not seem to have been so well "fired" as at Canterbury, and in many cases has perished altogether. This seems to have happened in recent years, for Mr. Westlake shows many details in his drawings of the glass which I cannot now distinguish. Where the painting remains we find that in a few of the medallions the drapery is drawn in the stiff manner of the twelfth and very early thirteenth century, but in most of them the later more flowing treatment prevails. In some, too, the blue of the backgrounds resembles that used at Canterbury, but in many, and notably in the north rose, it is of a purplish colour and much less agreeable. In a few it is of quite a grey blue. Nowhere can I trace the same hand as at Canterbury, and the borders and ornament are quite different; but that the artist had access to some at least of the same designs is shown by a medallion in the south choir aisle which represents Noah receiving the Dove, and is practically a replica of the Canterbury one in Plate IV., with a boat-like hull added to the Ark. It is not, however, nearly so good. According to Mr. Westlake the work at Lincoln strongly resembles that at Bourges, and to me it has something in common with that in the Sainte Chapelle at Paris. Lincoln Cathedral was not finished till after St Hugh's death in 1199, so none of the glass can be older than that. On the whole, I think the bulk of the glass is a little later than any but the very last of the work at Canterbury, that it is by a different hand, and shows less taste both in colour and design. Probably it was done between 1220 and 1240. [Sidenote: The south rose.] I am confirmed in this view by the examination of the fragments which fill the great south rose, which consist entirely of thirteenth century ornament and most probably once formed the setting of these same medallions. A little of it is scroll work, but the greater part is "mosaic diaper" of the kind shown in Plate VIII., and which is so characteristic of French work after 1220, whereas we only find it beginning at Canterbury. Some of the medallions are, however, very interesting, the best being those in which the drapery shows the earlier treatment. In the north choir aisle is a good one of the Israelites crossing a Red Sea of a fine streaky ruby, and in the south choir aisle is one of St. Thomas à Becket being conducted to Heaven by angels and carrying the damaged top of his head in his hands. By a touch of realism both parts of his head have been made of glass that has slight ruby streaks in it, giving it a gory appearance. This is the earliest example I know of the deliberate use of an accident of colouring in the glass to produce a realistic effect.