By the eighteenth century, however, they had adopted the German system. The President De Brosses, in one of the admirable letters that he wrote from Italy (1739), when describing the manufacture of mirrors at Murano, gives a vivid account of the cylinder process. Footnote 157: Not really steel, of course, but a kind of speculum metal containing about one part of tin to two of copper. Fioravanti, in his _Specchio di Scientia Universale_, tells us that this _acciaio_ was made of equal parts of brass and tin. He contrasts the German and Italian methods of preparation of glass mirrors, giving the preference to the former. Fioravanti then speaks of the interest taken in these mirrors—not by women only—and after balancing the pros and cons, he concludes that, on the whole—‘_gli specchi son’ mala cosa nelle case_.’ Footnote 158: A word that must not be confused with the term _luse_ or _lustro_, applied by the Venetians to a mirror. Footnote 159: There is a magnificent chandelier of this class in the drawing-room of Mr. Beaumont’s house in Piccadilly. It dates probably from the early years of the eighteenth century. Footnote 160: ‘_Notizia delle opere d’arte._’ I quote at second-hand, as I have not been able to find a copy of this work. Footnote 161: The learned Cardanus, physician, mathematician, and astrologer, has a section on glass both in his _De Subtilitate_ (1551) and in the somewhat later _De Varietate Rerum_. He is often quoted as an authority on the subject by contemporary and later writers, but in spite of many quaint and ingenious reflections I can find little of practical value in his remarks. Footnote 162: Not to be confounded, says the writer, with the stone known as Magnese, found ‘_nella Magna_’ (Allemania or Germany). ‘Quite other are the virtues of this stone [magnetic oxide of iron?] when placed under your pillow, ...’ but for the context I must refer the reader to the sixty-ninth section of the original work. Footnote 163: In the fourth section of the second treatise the author speaks of ‘_azurro della Magna del quale si tinge il vetro_.’ There is also a section at the end of the first book on the preparation of _azurro fine_ from _pietro d’azurro ultramarino_, but I do not think that this has anything to do with the colouring of glass, as it is associated with recipes for dyeing grey hair of a blonde colour and for preparing the _acqua virgine_ by which the face is rendered beautiful. It is difficult to understand what relation the _Acqua di Philoseophy_ (_sic_—there are several sections so headed at the end of the treatise) has with the preparation of glass. But all these old formulists are only too ready to run off at a tangent to discuss questions of alchemy. Footnote 164: