Gfihe Terrestrial Ghhe. 9.Z1 



the thermometers in present use. M. Libri found, for example, in 

 this way, that the zero upon the del Cimenio scale, corresponds 

 to — 15° of Reaumur ; and that the 50° of the former is identi- 

 cal with the 44° of the latter ; and that at the freezing point the 

 thermometer del Ciniento stands at 30° 5', &c. &c. 



Provided with these results, M. Libri has taken the maxima 

 and minima of each month during the sixteen years included in 

 the long lost registers, and he has compared them with analo. 

 gous results, which observations made since 1820 have afforded 

 him, in the Observatoire des Ecoles Pies of Florence. This ta- 

 ble has led to the important conclusion, that the clearing the 

 wooded mountains, effected some sixty years ago, has not, in Tus- 

 cany, led, contrary to the very general opinion, to any sensible 

 diminution of temperature. In the sixteenth century, the Apen- 

 nines were covered with forests, and notwithstanding, in the 

 space of fifteen years (from 1655 to 1670), Father Raineri 

 saw his thermometer one year at 23°, another at 22°, a third at 

 15°, and finally, a fourth at 9° (Fahrenheit), excessive colds, 

 which were not reached in the extraordinary winter of 1829-30. 



In the table of M. Libri, the column of the maxima of tem- 

 perature appears to offer a very important result. It would 

 clearly appear from it, that, in the sixteenth century, the sum- 

 mers in Tuscany were much hotter than they now are. The 

 observations of Raineri indeed present five maxima of 99°, two 

 of 101°, and one of 102°. Between 1821 and 1830, the ther- 

 mometer has only once stood at 99°. Thus the modification 

 which the climate of Tuscany seems to have undergone is that 

 of winters less cold, and summers less hot. 



The learned geometrician, to whom we owe the discovery of 

 the graduation of the thermometer del Cimento, would render 

 an additional service to science, by examining if the observations 

 of Raineri confirm the preceding result, not only as it regards 

 the extreme degrees of heat and cold, but also in relation to the 

 whole of the temperatures of each month, that is to say, to what 

 is very properly denominated the mean temperatures. 



XIV. On the Changes in the ClimcUe of France. 

 The agricultural documents which will now be submitted to 

 the attention of the reader, appear to establish that, in certain 



VOL. XVI. NO. XXXII. APRIL 1834. II 



