BAROMSTRlAt CHANGES." ^^J 



Twenty ninth of September. 



From 10 (28th) to 4 A. M. fell \l -^ 



From 4 to 10 A. M. rofe I ^V 



From 10 A. M. to 4 P. M fell 1 ^V 



From 4 to 10 P. M. rofe 1 



The obfervation on the 30th were to the fame effefl ; and 



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



of the atmofphere produces in the barometer a variation ofThe effeil Is _,,^ 



about 1 line -j^- Englilh, correfponding, as M. Lamanon re- ^';"J^''j|j?"^^^ 



marks, to a height in the atmofphere of nearly 100 feet, the computed 



According to Bernouilli, the aftion of the fun and moon ^.^^'J°^^P*'^"*= 



fliould produce a tide of feven feet, and according to Mr. 



de la Place, a tide not nearly fo great. 



It ftiould beobferved, that when thefe obfervations were Situation of the 



made, the moon was in her laft quarter, and the fun a few ^"" '""^ "^°p"» 

 J , /• 1 r , rw^i I • 1 .and place of the 



degrees to tlie louth or the equator. The latitude on the /hip. 



$8th was 50' north, and 1 1' north on the 29th; in the night Shewas/ir oar 



between that and the 30th, the fliip crofl^ed the line; and on^'/'*' 



%he 30th at noon, the latitude was 42' fouth; the longitude 



t\\ this while between 17** 3l' and 18° 33' weft of Paris, by 



the time-keeper; fo that the coaft of Africa, which was the; 



Oieareft land, was difrant about 8** of a great circle, and the 



American continent about \9°. 



The agreement between thefe, and Dr. Balfour's obferva- Argreement be- 



tlons at Calcutta is very remarkable. Dr. Balfour found that q^^^,^^^^^ 



during the whole lunalion, in which he obferved the baro-and thofeof Dr, 



meter from half-hour to half-hour, the mercurv conftantl y fell ^a'/o""" "f 

 n . , . . • /- ■' . . Calcutta. 



jrom 10 at night to 6 m the morning ; from 6 to 10 in the 



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



again ; and laftly rofe from 6 to ] at night. The 7naxifnufn 



height is therefore at 10 at night and 10 in the morning, and 



the minimum at 6 at night and 6 in the mornings The only 



difference is, that in Mr. Lamanon's obfervations, the 



minimum is Hated to have happened about 4 inftead of 6. 



This, however, will not feem a very material diflTerence, 



when it is remembered, that the inflant when any quantity 



attains either its greateft or its leaf! ftate is not eafily afcer- 



tained with precifion. From thi obfervations as detailed by 



M. Lamanon, the time of the minimuvt feems to anfwer fully 



3s well to 5 as to 4 ; fo that the difference of the refults is in 



; every 



