29th Sept. 



HIS TORT of tbe SOCIETK 5 



•From 10 (28th) to 4 A. M. fell I /. t'^ 



From 4 to i o A. M. rofe i r-^ 



From 10 A. M. to 4 P. M. fell i tt 



From 4 to 10 P. M. rofe i 



The obferv^Jitions on the 30th were- to the fame effedl ; and 

 hence it is concluded that at the equator the flux and reflux of 

 the atmofphere produces in the barometer a variation of about 

 I line To Englifli, correfponding, as Mi Lam an on remarks, to 

 a height in the atmofphere of nearly 100 feet. According' to 

 Bernouilli, the acflion of the fun and moon fliould produce a 

 tide of about 7 feet, and according to Mr de la Place, a tide 

 not nearly fo great. 



It fliould be obferved, that when thefe obfervations were 

 made, the moon was in her laQ: qijarter, and the fun a few de- 

 grees to the foLith of the equator.-ii.The latitude on the 28th 

 was 50' north, and 1 1' north on the 29th ;^ in the night between 

 that and the 30th, the fliip croflTed the line ; and on the 30th 

 at noon, the latitude was 42'fouth : the longitude all this while 

 between 17° 31' and 18^ 33' weft of Paris, by the time-keeper ; 

 fo that the coaft of Africa, which was the neareft land, was di- 

 ^ant about 8 ° of a great circle, and the American continent 

 about 19°. 



The agreement between thefe, and DrBALF0u,5;.'s, obfervations 

 at Calcutta is very remarkable. Dr Balfour found that du- 

 ring the whole lunation, in which he obferved the barometer 

 from half-hour to half-hour, the mercury conftantly fell from 

 10 at night to 6 in the morning; from 6 to 10 in the mor- 

 ning it rofe ; from 10 in the morning to 6 at night it fell again ; 

 and laftly, rofe from 6 to 10 at night. The maximum height" is 

 therefore at 10 at night and 10 in the morning, and the mini- 

 mum at 6 at night and 6 in the morning. The only difterence 

 is, that in Mr Lamanon's obfervations, the mtnimimi& ftated 

 to have happened about 4, inftead of 6. This, however, will 



not 



