Galileo's Shopping List
GALILEO’S SHOPPING LIST: AN OVERLOOKED DOCUMENT ABOUT EARLY TELESCOPE MAKING Giorgio Strano* Introduction During the first half of the seventeenth century, Italian telescope mak- ers usually kept maximum secrecy concerning their methods of grind- ing and polishing lenses. On the one hand, it was a point of honour to produce the best lenses and to prevent anyone from equalling their ability. On the other hand, rivals and plagiarists were always eager to reveal the procedures that could grant a leading position in the tele- scope market. A few examples may suffice to make this fact clear. Around 1637, the Neapolitan optician Francesco Fontana tried to sell telescopes to the Medici Court in Florence. Fontana, however, was told that his lenses were of inferior quality, or equivalent, or just marginally better than those already produced in Florence. Despite this criticism, the Medici Court made unsuccessful attempts—via Benedetto Castelli—to steal the secret of Fontana’s method of polish- ing the lenses.1 A few years later, in 1647, the natural philosopher and optician Evangelista Torricelli passed away suddenly at the age of 39. This event prompted the Grand Duke of Tuscany to set up investigations immediately to try to recall from the grave Torricelli’s lens polishing secrets. Witnesses that had had access to the departed’s house and could have observed him at work, were summoned to the Court and * This article is the development of Giorgio Strano, “La lista della spesa di Galileo: Un documento poco noto sul telescopio”, Galilaeana 6 (2009), pp. 197– 211. I would like to thank Karen Giacobassi for her kind support in revising the English text.
[Show full text]