DOVE ON THE LAW OF STORMS. 199 
ate consequence of the other, we may not be able to infer with 
certainty that the same effect might not have been produced in 
some other way. 
If barometric minima almost always occur when the atmo- 
sphere is agitated by tempests, on the other hand we frequently 
see a very low barometer, when mild vernal breezes interrupt 
the severe cold of winter and appear to introduce the tempera- 
ture of a more genial season. As it seemed however difficult to 
believe that such gentle winds could cause any considerable dis- 
turbance in the equilibrium of the atmosphere, the great dimi- 
nution of pressure on such occasions has been attributed to other 
causes. The idea that the convulsions of the surface in earth- 
quakes could not be unconnected with the atmosphere, was one 
of such natural occurrence, that the barometer was always looked 
to in the expectation of its indicating these phenomena at 
great distances. This idea appeared to be confirmed, when, four 
days after the destruction of Messina in 1783, the barometer in 
Europe fell unusually low. Van Swinden accordingly inferred a 
connexion between the two phenomena; but on a comparison 
of the meteorological observations made at the time, and recorded 
in the Manheim Ephemerides, Brande found that on the 9th of 
February the barometer fell below its average height by 14 lines 
in Lyndon, in Rutlandshire ; 133 in Amsterdam and Franeker ; 
12? in Dunkirk; 123 in Middelburg; 123 in Paris; 114 in 
Laon, Nantes, and Cambray; 103 in Brussels, Chartres, Poic- 
tiers, and Rochelle; 10 in Troyes and Montmorenci; 9 at Got- 
| tingen, Mayence, Metz, Limoges, and Bordeaux; 8 at Copen- 
| hagen, Erfurt, Wiirzburg, Lyons, Mezier in Guyenne, and Ole- 
ron; 7 at Spydberga in Norway, Stockholm, Berlin, Vienna, 
Manheim, Geneva, and Vienne; 6 at Sagan, Prague, Regens- 
burg, on the St. Gothard, and at Montpelier; 5 at Marseilles 
and Montlouis; 4 at Ofen and Padua; 3 at Petersburg, Mafra, 
Bologna, and Rome. Thus it appeared that the barometer was 
lowest in England and Holland, and that in approaching Italy 
it differed less and less from its mean height, so that the inde- 
pendence of the two phenomena became highly probable. 
If, as in this instance, such simultaneous observations some- 
times serve to show, that what had been regarded as evidence of 
essential connexion was merely an accidental coincidence be- 
tween two independent phenomena, we have much reason to 
hope that a careful examination of such observations may lead 
