368 
REPORT—184?. 
defined phaeDomena tliat may be recognised year after year, and girt k 
the curves of barometric rise and fall during the period of their oeconwa 
a peculiar symmetrical appearance. 
Second. On examining each individual curve, and carefiillydisciBBi^ 
the barometric differences between the stations, we are led to the tame n 
• ulls at which we arrived in our investigation of the syrametrioil wiTf« 
J842,—that two systems of waves or currents, one liavingapCT«o/dirKtK 
of prepress from the nurtli-west, the other from the sonth-tt'c*t,traverseiili 
ar«*a during the period of the great wave. The relative positions of tli*' 
wavtw are somewhat different to those of the individual waves of IWJ 
There are however these points of similarity, the north-west systems ahh 
in each case the laigest waves, both as regards amplitude and altitude; ’■ 
have already seen tliat the intervals between similar phases of norti-wt 
waves were nearly equal in 184-2 aJid 18*6, and also that during the inieni 
that elapsed between the transits of these similar phases, both in 
184-6, the same numbe.r of south-westerly waves passed over the ua 
HrusseU appears to be situated in or near the point where these difiatstlj- 
directed waves most usually cross each other, and this to a great wW 
explains both the nodal character of Brussels, and the production oftheps: 
symmetrica! wave or curve. 
It appears highly probable, from the examinatiou of the obserratioD*'' 
last autumn, that we have not only ascertained another return of thep'® 
symmctrioal wave, but have also detected the return of at least ihreeoi^- 
iiidividuai vvaves contributing to its production. 
IJiird. 1 he very precipitous fall characterizing the posterior 
the north-west system is another striking similarity which is developed l>|f 
liu‘discussion of those observations. Although at Ramsgate, 
Jers^, the barometric movements are gentle and greatly in aceordasM ‘‘W 
the Brussels movements, yet in the norUi-west the fall is piecIpilou.»« 
towards the close of the wave very rapid. At the Orkneys the 
of 18*2 and 1846, about the same part of the great wave, in each cssrp^^® 
great similarity in this respect. 
We now pass on to notice as briefly as possible the actual phttowneM 
occurred over the area embraced by the observations during theped®' 
of the great wave. ^ 
At the commencement of the great w’ave the posterior slope of* 
we* w avc extended from Ramsgate towards the north-west; it 
I *f ®**^®*^*‘^*' subordinate maxima of the symmetrical curve 
c(}( by the crests of tvo waves from the south-west, the second , 
general altitude in the north-west of about *2 higher than the fiM? 
K -- — Hui-tu-wesi or aooui * 2 r iiigner man me «***’ “ , 
e u crests nearly* two days. These waves were succeeded by 
from the. south-west with a still greater altitude; this third wave froj “ 
wuth-west formed the crown of the symmetrical cun-e. The 
slope of the north-west wave at Ramsgate is cleariy pcr«pf», 
interacting the rise resulting from the anterior slope of the second 
l» ^ some degree contributes to the symmetry of tbcc" 
ijy the time the crest of the third south-westerly wave transits the ai^ 
a ri succeeding north-west wave approaches, and 
barometer in Uie north-west, while it is falling iu the souw;® 
the rrit* of the tliird south-west wave. On the 
transits, and is inimedialely succeeded 
north-westerly wa precipitous slope that usually cbaracU’nstt 
nring the transits of these waves there appears to have existed a 
