160 Proceedings of Learned Societies. 
fall, and that the mercury ftood comfider- 
ably higher when the wind was from the 
fouth fide‘of eatt and weft, than in fimilar 
weather it did when the wind came from 
ras nerth-fde ; but untilit is known what 
e the winds that occafioned the mer- 
cury to alcend, and what to defeend, 
upon the other coafts of Auftralia, it will 
probably be not agreed, whether it rofe 
m confequence of the fouth-winds, bring- 
ing in a more denfe air from the polar 
revions, and fell on its being difplaced by 
that which came from dhe tropic; ar. 
whether the mfe and higher ftandard of 
the mercury was wholly, or m part, Oc- 
cationed by the firft fete r 1ea-W nds, and : 
the defeent becaute thofe from the vorth- 
ward came from off the land. = 
The height, at which the mercury ge- 
gerally ftood upon the fouth ‘coaft, de- ° 
jertes attention: it was feldom down to 
29°40. Of one hundred and _fixty days, 
irom the beginning of December, to 
May, it was nearly one-third of the time 
above thirty inches; and the fecond tinie 
of patling along the coatt, from the 15th 
ef, May, to the 1t of June, it only once 
defcended to 29° 96, and that fora few 
hours only ; its average ftandard for thefe 
listeen days being 30°25. Upon the 
eaftern half of the coatt beyond Cape 
Catatirophe, in March, April and May, 
the mercury tlood higher than it did on 
the wefiern half m December, January 
and February: the average ftandard of 
the firft was 20°09, but that of the latter 
only 29°94. At the Cape of Good Hope, 
the mean height of the barometer, during 
eighteen days in October, and November, 
was 30°07. The height of the mercury 
was taken at day-break, at noon, and at 
gabe in the evening. 
“From other obfervations, Mr. Flinders 
found the barometer of great ufe to him, 
in the invefligation of the dangerous part 
of the eafiern coaft, where the ihip was 
commonly furrounded with rocks, fhoals, 
iflands, or coral reefs, Near the ‘niain 
land, if the fea-breeze was dying off at 
night, and the mercury defcending, he 
mide no fcruple of auchoring near the 
fhore ; knowmg there would either be a 
calm, or a wind would cbme off the land; 
but if the mercury kept op, he ftretched 
off, m the expectation that it would be 
trefing up in a few hours. Among the 
barrier reefs, when the wind was dying 
away, the barometer. indicated with ale 
roft certainty, «from what quarter it 
would next foring up. if the mercury 
fiood about $015, and was Tif ine, the 
i trade wind: might be ~ex <peéted : 
3 
[March T, 
and if higher, that it would be well from 
the fouthw ard, or would blow frefh; and 
if it was up te 30°30, both. The falling 
of the mercury to 30°10, was an mdica-~ 
tion of a breeze from the north-eaftward ; 
and its defcent’ below SO inches, that it 
would fpring up or fluft round to the 
weltward.  ~ 
In a general fammary of the winds on 
the caft coaft, thofe that came from the 
fouth and eatt, caufed the mercury to 
AHE aiid {tand highett: The winds Troi 
north-eutt, kept the mereury Up above 
30 ineles. on the eatterh coatt, and cauled 
it to‘rife after all other winds, except 
:.thofe from the fouth-eaftward ; but on the 
fouth coaft, the’ mercury fell with thein, 
and ftood contiderably below 30 inches. 
During north-weit “winds,, the mercury 
ftood lower than at any othe? time upon 
both coafts. Moderate winds from the’ 
fouth- weftward, with fine weather, caufed 
a deifcent of the mercury on the eaft 
coaft; and during their continuance, It 
was much lower than with winds from 
the north-eaftward; but upon the fouth- 
coaft it rofe with fouth-welt winds, ang 
ftood much higher than when they came 
from the oppolite quarter. 
The greateft range of the mercury on 
the eait coalt, was from 29°60 tu 30°36 a 
Port Jaco’: and within the tropic, 
from 29°88 to 50°30; whilft upon the 
coatt the range was froin 29°42 to; S0'5T, 
in: the weftern part, where the latitude 
very little exceeds that of Port Jackfon. 
After a number of very imterefting and . 
important remarks, Mr. Flinders con= 
cludes with tome general remarks upon 
the barometer, which, from his own ex- 
perience, he conceives may be ufeful te 
fermen, (1.) It 1s not fo much the ab- 
folute, as the relative height of the mer- 
cury, and its {tate of rifing and falling, _ 
that is to be attended to in forming 2 
Judgment of the weather that will fuc- 
ceed ;’ for it appears to ftand at different 
heights, with the fame wind and weather, 
in different latitudes, (2.) In the open 
fea, the changes in the weather, and the 
firen: vth of the wind. principally affect the 
barometer: ; but near thé thore, a ehange 
in the direction of the wind feems.to 
atieét it fullas much, or more, re either 
of thofe.caufes taken fingly. (3.) It is 
rots the fouth and eaft ‘coafts of any 
country in the fouthern, or north and 
eat coatts in the northern hemifphere, 
where the effect of fea and land winds 
upon the barometer is likely to be moft 
confpicuous. (4.) In the open fea, the 
mercury itands: higher in a fteady breeze __. 
of 
