X 



710 



These results are even confirmed by older 

 observations than those of Lamanon. M. San- 

 chez Dorta has published in the greatest detail, 

 in the first volume of the Memoirs of the Aca- 

 demy of Lisbon, the barometric heights ob- 

 served at Rio Janeiro, at three periods of the 

 day, (morning, noon, and evening) during the 

 whole year of 1785. In this table, of more than 

 a thousand observations *, we scarcely find two 

 or three days in a month where any irregularity 

 is remarked} but the hours indicated not being 

 precisely those of the extreme limits, it is better 

 to have recourse to the table in which M. Dorta 

 gives for ^very month the mean bf the hours 

 18 h , 20V 22h, 24 h , 2V4 h , 6 h , 10 h . 



* Mem. da /icademia Real das Sciencias f 1799, Vol. i, p. 

 397. The barometer was of the construction of M. de Ma- 

 galhaes. 



