80 



tables and animals \vhicii subsist and mnlliply there 

 liatiirally, and do not on our sea coast. Thus Catalpas 

 grow spontaneously on the Mississi|)pi, as far as the 

 latitude of 37°, and reeds as far as 38''. Perroquets 

 even winter on the Sciota, in the 39th degree of lati- 

 tude. In tlie summer of 1779, wlien tlie thermometer 

 was at 90° at Monticello, and 9(5 at Williamsburgh, it 

 was 110^ at Kaskaskia. Perhaps the mountain, whicli 

 overhangs this village on the north side, may, by its 

 reflection, have contributed somewhat to produce this 

 heat. The difference of ten>perature of the air at the 

 sea coast, or on the Chesapeake bay, and at the Alle- 

 ghaney, has not been ascertained ; but contemporary 

 observations, made at Williamsburgh, or in its neigh- 

 bourhood, and at Monticello, which is on the most 

 eastern ridge of the mountains, called the South west, 

 where they are intersected by the Rivanna, have fur- 

 nished a ratio by which that ditference may in some 

 defrree be conjectured. These observations niake the 

 difference between Williamsburgh and the nearest 

 mountains, at the position before mentioned, to be on an 

 average (Pl-8 of Farenheit's thermometer. Some al- 

 lowance, however, is to be made for the ditference of 

 latitude between these two places, the latter being 

 38^8' 17', which is 52' 22" north of the former. By 

 contemj)orary observations of between five and six 

 weeks, the averaged and almost unvaried difference of 

 the heijrhth of mercury in the barometer, at those two 

 ]»laces, was .784 of an inch, the atmosphere at Monti- 

 cello being so much the iigluest, that is to say, about 

 one thirty-seventh of its whole weight. It should be 

 observed, however, that t!ie hill of JMonticello is of 500 

 feet perpendicular heighth above tlje river which 

 washes its base. This position being nearly central 

 between our northern and southern boundaries, and 

 between the bav and Alleghanev, mav be considered as 

 furnishing the best average of the tem[)erature of our 

 climate. Williamsburg is much too near the south 

 eastern corner to give a fair idea of our general tem- 

 perature. 



