The world’s earliest instrumental temperature records, from 1632 to 1648, claimed by G. Libri, are reality or myth?

Abstract

In 1830, Libri announced the finding of a 16-year-long record of daily tempera- ture observed in Florence, Italy, by Father Renieri before the activity of the Medici Network (1654 to 1670) that is usually considered the earliest instrumental series in the world. The Libri announcement was supported by the concurrent finding of a box with the early Little Florentine Thermometers that survived the Inquisition and was confirmed by Schouw, von Humboldt and Maxwell. However, all investigations made to find Renieri's observations were fruitless. This paper clarifies this complex situation differentiating between myth and reality. A careful analysis of the Libri's announcement in the historical context points out that Libri made the announcement while escaping for conspiracy from Florence and needed a scoop to be introduced in the French Academy of Sciences. For this reason he made a deliberate mix of new and old assertions, i.e. he claimed to have made new discoveries but without explaining too much and reporting misleading details about well known stories concerning the earliest meteorological observations. This induced people to suppose that further, earlier records existed. The consequence of this was that climatologists searched for years the claimed records. This paper shows that the Medici Network almost certainly contains the earliest exploitable instrumental observations. The possibility of finding a short series of observations prior to 1654 is remote.