145 
of Edinburgh, Session 1866-67. 
the barometer was low in Western Europe. The same principle 
that regulates the sea-breeze on our coasts in summer, regulates 
the motions of the winds in storms. 
The south-westerly current that blows above in the high latitude 
is usually felt at the surface in France and the Mediterranean eight 
or ten hours before the passage of the minimum barometer. It 
blows obliquely across the isobarometric lines, and, in contra- 
distinction to Espy’s views, obliquely from the line of minimum 
barometer. When the difference of pressure is great betwixt the 
isobarometric lines, the wind blows violently from the south, at 
lirst changing to the south-west, on the passage of the low baro- 
meter, and then to the west and north-west, becoming a part of 
the general cold and dry current which raises the barometer. 
The cold and dry current prevailing from the west, causing the 
rise of the barometer, imparts form to the line of minimum baro- 
meter. This line is of great length, and frequently nearly straight, 
and for obvious reasons, when bent, it can only be largely bent with 
its convex side towards the east. It is often greatly curved in 
the slow- moving storms of autumn, when north-easterly rainy 
winds are largely developed on the north-eastern part of storms. 
In regard to storm- warning, it was contended that, as storms all 
issued out of the Atlantic, a day and night watch at Valentia, on 
the west coast of Ireland, was indispensable to give warning of such 
rapidly-moving storms as those of December 1863. That storms 
all travelled from west to east was established eighty years ago, 
through the labours of the Meteorological Society of the Palatinate, 
and had been completely verified by the experience of Signor 
Matteucci, the distinguished director of the Meteorological Depart- 
ment in Italy. Every country in Europe must watch the develop- 
ment of storms as they pass to the east on the latitudes on which 
they are situated. It was shown that it is highly probable that great 
breakings up in our weather may be telegraphed from Newfoundland. 
2. On the Vapour Lines in the Spectrum. By Sir David 
Brewster, K.H., F.K.S. 
In the year 1842 I discovered that the luminous and brilliant 
lines in the spectrum of certain flames, since called vapour lines , 
corresponded to certain dark lines in the solar spectrum. 
VOL. VI. 
T 
