356 
REPORT—1847. 
»ion, but also (w’ith the exception of this protuberance) being conBider# 
Mow all the other curves. This, which at first sight appears as a very a» 
malous character, is clearly explained by the presence of a ridge ofpr^rr, 
hereafter to be noticed, existing in the neighbourhood of Arbroath, of tiib 
the low pressure at Galway appears to be the posterior trough. This is bom 
out by the pressure at Limerick so far recovering as to be classed aaonj tk 
liorth'Wcst curves. 
i he 1/irnenck and tlelstone curves exhibit a somewhat symmetrica! ilim 
nation of pressure. Until midnight of thefitb the barometer at Helstuoen 
higher than that at Limerick ; at this time both barometers were rising bi 
that at Limerick much more rapidly than that at Hclstone. Helslone ataiofl 
lU principal njaximuiii, the crown of the great wave, on the9tb; frumlls 
time to the 12th the movements at both stations were opposite* rising 
nt Limerick, falling slightly at Helstone. After the passage of tie leec* 
maximum, which occurred earliest at Limerick, the curves converge,*^ 
cross about 9 I’.m. of the 15th at nearly the same altitude as that at slid 
they intersected on the b’tb. 
During the first eight days the Helstone curve is found ainongtlMf 
the north-western group. From this group it considerably divergi^s ^ 
interval between the poaxoges of the two crests on the 9th and IStli, and* 
ag.^ii found iiniong the north-western curves after the 14th. 
The curve repK!8enting observations at St. Heller, Jersey, presents aiti> 
king resemblance to those of MeUtone and Limerick, until the maxiotm** 
the 9ih after this date it more closely follows the Helstone citfve- Tk 
mtcrsecllons of the three carves occur nearly at flic same epochs as the inW' 
sections of the Helstone and Limerick curves, — midnight of the6d>i»J 
noon of the J.5th. In many respects the Jersey curve resemblrt " 
Kainsgute; and it closely agrees with the Helstone curve, in being altoget^ff 
toiler and not intersecting the Kamsgate curve. 
Urn whole extent of the Hritish Isles is divided into two baromwnc an*, 
distmguished in one case liy the superiority of the maximum ofthe9tli.t/|f‘ 
or the wntral or crowning wave of the great symmetrical wave; and w 
other by the superiority of the maximum of the 12th, that of tfaefintwl;; 
ordinate wave on the posterior slope. A line passing between ArbtMth »»f 
^wcasde, south of Dumfries, and between Ireland and Wales, sepanitci die* 
line we find the maximum of the 12th soi^' 
a Id attaming its greatest altitude at Arbroath. South-east of Ihh line J 
nw.!.- of the 9th superior. The following Table exhibit? thedf 
^ niaximum of the 12th below that of the 9tb. It will be«« 
IS epressjon increases towards the south-east angle of our islwd' 
Depression of the 
Station. 
Applegarth. 
Makerstoun 
Hobbs* Point .. 
Newcastle 
Tlelstone. 
Downcss. 
Drecon 
Table V. 
Alaximum of the 12tli of November below that of the 
of November, 1847. 
Depression. 
Eng. in. 
. '000 
Station. 
. -004 
. -020 
Weston-super-Mare . ^ 
*nQT 
. -037 
. -050 
. '050 
Jersey. 
