49 Transactions.— Miscellaneous. 
reciprocating the movements of the curves upon either side of it, and every 
advantage must be taken of river-channels, mountain-passes, and other 
such routes by which the contours ean be shown to make their way across 
the country; the state of the sea, especially at exposed places, must also 
be carefully shown by these contours; and by close attention to these 
principles, the occurrence of gales at points far distant from each other, 
and the existence of but moderate winds at places close to where such gales 
exist, can be accounted for, and reason can be shown why the sea- 
disturbance is subject to similar irregularities, all apparently the effect 
of purely local causes working independently of each other, but which are 
in reality part of one system, whose effect is intensified at these points. 
The isobaric contour also enables another difficulty to be accounted 
for; viz., the fact that the barometer moves more rapidly at some places 
than it does at others; and why, after it has fallen from a high point at 
all stations, there are frequent instances of its not recovering its original 
position over a considerable extent of country for a long time ; for instance, 
let it be assumed that pressure ranges between 80°50 in the northern part 
of this colony, and 30:20 in the south, and that a fall takes place amounting 
to about seven-tenths of an inch in the latter, and two-tenths in the former 
districts ; now, when a recovery sets in it will be found that the barometer 
seldom rises to its original position at all places by a difference not unusually 
amounting to half an inch at the southern stations, and although rapid 
oscillations may take place in that part of the colony, yet pressure south- 
ward of Napier does not return to its original position for a period varying 
from a few days to several weeks. 
This general position of the lower pressure toward the south is in 
accordance with our meteorological knowledge of this hemisphere, but it 
does not seem to offer an explanation of why high readings of the barometer 
in the south are not so unusual as may generally be supposed, and it should 
render forecast easy, as it gives a gradient showing westerly winds; but 
experience in storm-warning shows that easterly winds are frequent, and 
easterly gales must by no means be left out of the estimate of probable 
weather, especially at places lying south of the 40th degree of latitude, as 
it almost invariably happens that whenever the wind backs at Places south- 
ward of Napier it changes into north-east, although it does not always blow 
a gale from that quarter. 
In the attempt to account for some of these points the isobaric contours 
were of great value, and their use led to the idea of the possibility of the exis- 
tence of multipl lying sout} 1 of contours, or lines of higher pressure, 
whi ch sis. 4 H1 1 41 1 1 Fide: va 41 
wards when they have passed, or if they are passing at a considerable distance 
