ON ATMOSPHERIC WAVES. 55. 
conclusive evidence relative to it. It would consequently appear, in accord= 
ance with previous researches (Report, 1846, p. 147), that contiguous 
‘Masses of land and water exert a decided and ‘measurable influence on the 
variations of atmospheric pressure. In the case before us, the symmetry of 
the barometric curve is departed from in a greater degree at inland stations, 
a greater difference between the points selected being exhibited at such 
_ stations than at the sea-coast on either side. 
On turning to the last Report, pp. 357 and 358, we find the maximum 
of the 5th referred to a wave-crest that passed rather rapidly over the area 
from the south-west. The altitude of this crest was greatest in the south- 
east, simply because it was contemporaneous with a north- -westerly slope ; 
_aline from Jersey to Limerick on the chart will somewhat approximate to 
a transverse section of this slope. On page 364 of the same report, we find 
the maximum of the 12th referred to a wave-crest that came from the 
“north-west; and at p. 367, the departure from symmetry is referred to the 
greater development of this north-westerly wave. Stornoway, in the Western 
Isles, exhibited the greatest development of this wave, the greatest baro- 
Metric range during the passage of the ‘symmetrical curve,” and the 
greatest difference between the points selected as indicating the departure 
from symmetry ; and these phenomena clearly resulted from the greater 
altitude which the north-westerly wave attained in the north of Scotland; 
is would appear to indicate that the deviation from symmetry resulted 
from the greater altitude of the north-westerly wave in certain localities, and 
that the barometer had a tendency to rise higher over the land as the wave 
transited. It i is, however, difficult to determine this from the observations, 
partly on account of the slow-moving wave [I] (Report, 1847, p. 358), 
whose crest extended from Arbroath to Stornoway, and also from the south- 
westerly system of waves; for it is evicent that the same result, viz. an 
approach to an equality of altitude of the maxima of the 5th and 12th, would 
produced as well by the higher readings of the 5th as the dower readings 
fthe 12th. Upon the whole it appears highly probable that the result is a 
ompound one, the approach to symmetry, as we proceed from the north« 
t to the south-east, being occasioned by the higher readings of the south- 
terly crest of the 5th in the south-east, and the lower readings of the 
rth-westerly crest of the 12th in the same locality; the inflexions of the lines 
eing produced by the tendency of the barometer to rise higher as the anterior 
slopes and crests, especially of the north-west wave, passed over the land. 
Regarding the chart before us as indicating the localities and directions of 
ain barometric phenomena characterizing the ‘‘ great symmetrical curve 
November,” we at once see that it exhibits to us but a small portion of 
area over which these particular phenomena can be traced. ‘The lines 
deviation from symmetry, as determined from observation, extend from 
0 inch at Ramsgate to *550 inch at Limerick, *580 inch being the highest 
termination at Stornoway. [t would appear from the Galway observa- 
ons that the deviation did not much exceed *580 inch, *480 inch being the 
at this station. Query. Shall we find the curves undergoing such a 
m odification of form to the north-west of Ireland and Scotland as to bring 
se maxima more on a level, having other features, as the broad maximum 
f the 8th, which is very apparent in the Galway curve, so developed as to 
toduce a different order of curves, the limit of deviation from symmetry 
f the Greenwich type being somewhat in the direction of the *550 inch 
; ne ? The area of the British Isles embraces the north-western side of the 
Jeviation from symmetry, as determined by the inferiority of the maximum 
OLE PEO SENATE AO LIE PS, * 
PPR SS eer 
