THE BAROMETER AND THE WEATHER. 153 



paper weather charts for the dates of October 5th and 6th. 

 They are enlarged and printed more clearly than the ori- 

 ginals, with an explanation of signs at foot of the charts. 



It will be observed that, in the chart for October 5th, an 

 isobar of 29.2 runs up in a N.E. direction from between the 

 Orkney and Shetland islands, crosses the North Sea, strikes 

 the coast of Norway near Bergen, and then proceeds on- 

 wards towards Throndhjem. An isobar of 29.5 crosses 

 Scotland, following very nearly the line of the Grampians, 

 enters the North Sea about Aberdeen, and crosses to Chris- 

 tiansnnd; then runs up the Skager Rack and Christiania 

 Fjord towards Christiania. Another isobar of 29.8 crosses 

 Ireland through Connaught to Dublin, onward across Eng- 

 land by Liverpool and the Humber, over the North Sea, 

 and through Sleswig to the Baltic. These three are nearly 

 parallel; but now we find another isobar that of 30.2 

 taking quite a different course, by starting from the Bay 

 of Biscay about Nantes ; running on towards Paris and 

 Strasbourg, and then bending sharp round, as though 

 frightened by the Germans, and retreating to the Gulf of 

 Lyons by an opposite course to that on which it started. 

 On the following day all has changed; the northern isobars 

 are running down south-eastwards instead of north-east, 

 and are remarkably parallel. In the left-hand upper corner 

 of this chart is a note that "our west, north, and eastern 

 coasts were warned yesterday" Why was this? It was 

 mainly because the barometric gradient or incline was so 

 steep. On the 5th there was one inch of difference between 

 the Orkneys and the Bay of Biscay, or between Bergen and 

 Paris, while the barometer was still falling in Norway and 

 at the same moment rising in Ireland and France. On the 

 following day these movements culminated in a gradient of 

 1.4 nearly one and a half inches between Cornwall and 

 the ancient capital of Norway. 



What must follow from this condition of the atmosphere? 

 Clearly a great flow or rush of air from the south towards 

 the comparatively vacuous regions of the north. The gases 

 of our atmosphere, like the waters of the ocean, are always 

 struggling to find their level, and thereby the winds are 

 produced. The air flows from all sides towards the lowest 



