After the Restoration the issue of patents began again. Everything points at this time to a renewal of interest in Venetian glass. When, however, in 1663 the Duke of Buckingham obtained his licence, his claim was based upon the improvements he had made in the looking-glass plates and in the plates for the glass-coaches. As in France, sheets of large size and good material were now in demand for both purposes. It was somewhat later, it would seem, that he turned his attention to making hollow ware in the Venetian fashion. Although nitre, a salt of potash,[245] played an important part in the glass made by the duke, there is no proof that any use was made of red lead or of litharge. Evelyn, who in 1673 visited the duke’s ‘Italian glass-house at Greenwich where glasse was blown of finer metal than that of Murano at Venice,’ says nothing about such substances being employed. But in spite of this progress in the home industry, the importation of chests of glass from Venice was at its height in the reign of Charles II. This we see from the correspondence of a London glass merchant, one John Greene (1667-1672), with a Venetian firm, which has fortunately been preserved.[246] Along with these letters were found the ‘office copies’ of the patterns which Greene sent out to Venice as a guide to the glass-blowers. Here we have mention of ‘clouded calsedonia glasses’ for beer, claret, and sack, ‘creuits with or without feet, brandj tumblers,’ and ‘glasse floure potts.’ Not the least interesting item is the ‘Rhenish wine glasse,’ which is illustrated by a typical roemer with prunts on the stem, almost our only evidence of the use of these goblets in England. Greene advises his Venetian correspondent that the looking-glasses and the coach-glasses are to be packed at the bottom of the cases to escape if possible the search of the custom-house officials. What especially strikes one in examining the patterns of the drinking-glasses, which form the bulk of the orders (Hartshorne, Plates 30-32), is the fact that the stem or shank, so important a part of the eighteenth-century glass, is not yet developed; the conical bowl is separated from the foot by a simple or fluted bulb, or sometimes by two such bulbs or knops.