116 MARINE BAROMETETt. 



Observations ^^^^^ south and SW, and sometimes WSW, the mercury 

 and inferences being nearly stationai y at 30 inches ; but meeting with a 

 JheToTrc'lpon. ^^"^* °^ *''^ south-east trade wind in Latitude 24°, we 

 dent changes found it rise to 30,30 for two days. A westwardly wind 



of wind and brought it back, to 30 inches for a short time ; but on the 

 weather to be ° ' . 



expected after trade wmd finally setting in, it fixed itself between 30,20 

 change in the and 30,30, as long as the wind preserved its true direction. 

 meter. "* ' ^^^'' ^'^^^ month of September, 1802, and the greater 

 part of August and October, we spent upon the east coast 

 between the latitudes 23° and 17°. The south-east trade 

 is the regular wind here, but we had many variations. 

 Wliilst the trade prerailed, the average standard of the 

 mercury was 30,15, and the more southwardly it was, and 

 the fresher it blew, the higher the quicksilver rose, though 

 it never exceeded 30,30. When the trade wind was light, 

 it was usual for a breeze to come off the land very early in 

 the morning, and continue till eight or nine o'clock ; but 

 these temporary land Avinds did not produce any alteration 

 in the mercury, which ke})t at these tiroes about 30,10. 

 When the trade wind veered round to ENE, or more 

 northward, which was not seldom, the mercury ranged 

 between 30 inches and 30, 10; and when a breeze from 

 ' north or N by W prevailed, which was the case for a 



considerable part of twenty days we remained in Broad 

 Sound, its height was something, but not much less. These 

 northwardly winds I take to have been the north-east wind 

 in the offing ; which had been partly turned, and in part 

 drawn out of its direction, by the peculiar formation of 

 this part of the east coast. There are but few instances of 

 any steady westwardly wind prevailing ; when such hap- 

 pened, they were generally from the north side of west ; 

 and at these times the range of mercury was between 29,95 

 and 30,05, which was the lowest I at any time «aw it on 

 this portion of the cast coast. 



The barometer was of great service to me in the investi- 

 gation of this dangerous part of the east coast, where the 

 ship was commonly surrounded with rocks, shoals, islands, 

 or coral reefs. Near the main land, if the sea breeze was 

 dying off at night, and the mercury descending, I made no 

 ficruple of anchoring near the shore ; knowing that it would 

 either be a calm, or a wind would come off the land -, but 



if 



