The preparation of ‘_calcedonio in tutta perfezione_’ is next described, and I may note that the presence in it of salts of iron and copper, to say nothing of silver, mercury, and _azurro_, would point to some variegated mixture resembling the schmelz of later days rather than to the opalescent glass to which this name was subsequently given (cf. p. 206). Of greater importance than any of these little treatises is the work that Antonio Neri published in 1612. In fact, having regard to the influence of this book on future writers on the subject, especially upon those who sought to make glass by Venetian methods in England and elsewhere, it may without doubt be given the premier place as the most important work that has ever appeared on the preparation of glass. We know very little of the author except that he was born in Florence towards the end of the sixteenth century, that he was a priest, and that he spent some time at Antwerp, where it would seem that his attention was first directed towards the manufacture of glass. When, after the death of the Grand Duke Ferdinand in 1609, the manufacture of the soft-paste Medici porcelain was abandoned, we are told that in its place glass-works were established at Pisa, and with these works we may perhaps connect Neri’s little treatise. I have, however, already gone over most of the ground covered by this book in my quotations from Biringuccio and others, and I will postpone the consideration of what little further is to be gleaned from it until I come, in the account of our English glass, to speak of the translation of Neri’s book made by Merret in 1662. CHAPTER XIV THE FRENCH GLASS OF THE RENAISSANCE In the history of European glass the culminating point is perhaps reached in the Venetian glass of the first half of the sixteenth century—I am speaking, of course, from the artistic point of view. For a century or more after this time our history is concerned with little else than the spread of the Italian methods of manufacture and decoration over the west of Europe. After the middle of the seventeenth century the interest becomes more and more centred in the technical and economical improvements in the manufacture. The invention of plate-glass by the French, in England the use of coal instead of wood in the glass-furnace, and the adoption of a heavy fusible type of glass containing lead (an indirect consequence, perhaps, of this change of fuel)—these are the really notable points in the history of the first century of industrial advance. After the middle of the eighteenth century England takes a more and more important position, and the prominent question was the production of a glass of high technical excellence at a greatly reduced price. Preoccupied as we were at that time with the absorbing interest of this industrial revolution, less attention was given in this country to the artistic side in the manufacture of glass.