But this Venetian trade had now seen its best days; there are some hints of a falling off in Greene’s last two letters (1671-1672). On the other hand, during all this period the enterprising glass firms of the Netherlands kept up a close intercourse with England. As early as 1662 a patent for making various kinds of glass was obtained by one John Colenet, whom Mr. Hartshorne has very plausibly claimed as a member of the great glass-making family of Ghent and Namur, the De Colnets, so often mentioned in the letters of M. Schuermans. A few years later the tables were turned, for now the De Colnet firm was fain to engage an Englishman to produce ‘_verre à l’Angleterre_.’ In 1680 the great rival firm of Liége, the De Bonhommes, according to a document quoted by M. Schuermans (Letter vii.), was already making ‘_flint-glass à l’Anglaise_.’ Now this statement brings me face to face with what is the great crux in the history of English glass—the question, namely, when and where lead-glass was first applied to the manufacture of hollow ware. But first I must say a word of a little book published in 1662. This is the already-mentioned translation by Christopher Merret of the _Arte Vetraria_ of Antonio Neri (see p. 7). Merret, who was a man well abreast of the science of his day and an early, if not an original, member of the newly founded Royal Society, has supplemented Neri’s series of recipes with certain ‘Observations’ of his own. Here may be found some curious information concerning the materials used in the manufacture of the _cristallo_, for it is with this glass that the author is chiefly concerned. Merret does not appear to have had much acquaintance with the glass made in England in his day. For the practical details of the furnace and for the processes of glass-blowing he takes us back to Agricola. Both Neri and his translator are indeed for the most part occupied with the nature and preparation of the materials, and with the various methods by which glass may be coloured.[247] Neri, like all the old writers, knew of the merits of lead-glass in the preparation of pastes for the manufacture of artificial gems; in his sixty-first section he tells us: ‘Glass of lead, known to few in this art, as to colour is the finest and noblest glass at this day made in the furnace. For in this glass the colours imitate the Oriental gems, which cannot be done in crystal. But unless diligence be used all sorts of pots will be broken, and the metal will run into the furnace.’ Upon this passage Merret observes: ‘Glass of Lead! ’Tis a thing unpractised in our furnaces, and the reason is because of the exceeding brittleness thereof.’ Lead, he continues, is indeed the principal ingredient in the glaze of the potter, ‘and could this glass be made as tough as Crystalline, ’twould far surpass it in the glory and beauty of its colours.’ Thus we see, with Merret as with Neri, the great merit of lead-glass is the capacity possessed by it of