ON ATMOSPHERIC WAVES. 
355 
posterior subordinate wave. During the first six days these curves inter¬ 
sected as many times; upon the setting-in of the central wave they began to 
diverge, Stornoway being superior; the rise at both stations from 9 p.m. of 
the 6th to noon of the 8th was very rapid; the greatest amount of divergence 
occurred on the transit of the luaxitnura on the 12th; after which they 
converge until the 16th, when they run together. 
Table IV. 
Limits of Range, North-western Curves, Stornoway, the Orkneys, Largs and 
Applegarth, including Limerick. 
Epoch. 
Range. 
Epoch. 
Range. 
Nov. 2 .. . 
.. -27 
Nov. 10_ 
. -18 
3.... 
11 .... 
. -24 
4.... 
.. -12 
12.. .. 
. -26 
5 .... 
.. .17 
13.. .. 
. -24 
6 .... 
.. -17 
14.... 
. -22 
1 .... 
.. -18 
15.... 
. *23 
8 .... 
.. *18 
16.... 
. -23 
9.... 
.. -H 
17 .... 
. -18 
In consequence of the. greater development of the first posterior subordi¬ 
nate wave in the north-west, the symmetry of the great wave is destroyed in 
these localities : tJie two crestn arc clearly traceable in all the curves, although 
at the Orkneys and fitonioway the crest of the centrul wave ia considerably 
below that of its succeeding wave, so much so as to prevent its appearing 
even as a subordinate maximum. Obaervaiioiis from the following stations, 
Stornoway, the Orkucys, Largs, Applegarth Manse, St.Vigean’s, Limerick 
and Galway, all agree in reading tlie luaximum of the first posterior subordi¬ 
nate wave higher than that of the central w ave, and clearly mark out Scotland 
and the western parts of Ireland as the area, of the greatest development of 
this wave. 'J’he Limerick curve closely agrees with those at Stornoway and 
the Orkneys iu e.\hil)iting only one prineijial moximum—that of the I2th. 
From the 8th to the 12th, the barometers ut the Orkneys and Limerick ex¬ 
hibited equal pressures. The maximum at Limerick was somewhat similar 
to that at Largs, and after its transit the curves at the. stations were also 
somewhat similar. 
The Limerick curve may bo clnssoil with the north-western, not only as 
agreeing with the Stornoway and Orkneys’ curves in the greater development 
of the maximum of the 12ui, but also in its numerous intersections of the 
curves at Stornoway, Ijirgs, Applegarth and the Orkneys. From this we learn 
that during the period of the great wave over an area extending from Lime¬ 
rick towanls the north-oaot as far as ilie Orkneys, the barometric dift'erences 
did not exceed ’SO*. Galway is excepted from this class. During the ante-- 
rior slope of the wave the pressure at this station was generally *30 below that 
at the other stations, and with one exception always more than •20. 
1 he curve at Galway in Ireland ditfers most maioriolly from all the others, 
not only in its general form having a large protuberance on the anterior slope 
of the great wave, whicli gives the api)caranco of a broad crest, extending 
from noon of the 7th to midnight of the I2lh, with an intermediate depres- 
* This may he intcrestini;ly compared wUh tlie difTerences of Ramsgate and Stornoway, 
and goes far to show that the greater diffcTences of atinuipbcric pressure result more or less 
from the north-westerii system of waves, and that the greater oscillations approach ns from 
the north-west. 
2a 2 
