114 MAniXE BAROMETER, 



Observations latter only 29,94. At the Cape of Good Hope, the mean 



and inferences height in the barometer, during eii^htci-n davs' in October 



to ascertain , tvt , » » 



the correspon- ^"^ November, was 30,07. 



dent changes The marine barometer on board tlie Investigator, supplied 



weaXl-^tobe **^ ^^^ astronomer by the Board of Longitude, >vas made by 



expected after Nairne and J>lunt, and had, I believe, been employed in 



change in the one or more of the voyages of Captain Cook, and perhaps 



Dianne baro- • j.i, a c n ^ • tt t . . 



meter. *° *"^'' ^^ Captam Vancouver. I suspect, that it was not 



suspended so exactly in the proper place, as the latter instru- 

 ments of these makers probably are ; on which account, th* 

 motion of the ship caused the mercury to stand too high ; 

 and perhaps one or two-tenths of an inch might be deducted 

 with advantage from the heights taken at sea, but I think 

 ftot when the ship was lying steadily at anchor in the 

 harbour. The barometer stood in my cabin, and the height 

 of the mercury was taken at day-break, at noon, and at 

 eight in the evening, by the officer of the watch ; as wj^ 

 also that of the thermometer. 



The general effects produced upon the barometer by the 

 sea and land winds, on the east coast of Australia, will be 

 learned from the following abridgment of our meteorological 

 journal : 



1st. In the run from Cape Howe, in 37^° south latitude, 

 to Port Jackson, in 3i°, once in the month of May, and 

 once in June, I found that the mercury descended with light 

 winds from north, NW, west, and WSW ; Avhilst during 

 fresh breezes from south and SW it aScended, and stood 

 considerably above 30 inches; with the wind at NE and 

 NNE it also kept above 30 inches, but not so high, nor 

 did it rise so fast, as when the wind was from SSW. From 

 between south and east, the winds did not blow during 

 these times. This example does not difier so much from 

 those on the south coast as to be decisive of any thing. 



2c/. The observations made during a stay of ten weeks 

 at Port Jackson, in May, June, and July, 1802, are more 

 in point than almost any other. Strong eastwardly winds 

 were very prevalent at that time, and were almost always 

 accompanied with rain and squalls ; yet this weather was 

 foretold and accompanied by a rise in the barometer, and the 

 general height of the mercury during their continuance was 

 ' ^0,-20 : higher if the wind was on the south side of ESE, and 



low#r 



