i8 3 



proceed to explain what meteorologists are able to convey 

 by its use. 



I suppose that all of my hearers have read enough of late 

 years about depressions, which always bring bad weather, 

 storms in winter and rain in summer. Now I do not 

 mean to say that all our storms are due to depressions, 

 but by far the greater part of them are so, and for 

 the purposes of this lecture I shall only treat of such 

 storms. 



What, then, is a depression, or a cyclonic disturbance ? 

 it is a portion of the atmosphere in motion more or less 

 approximately circular, round a central point. At this 

 central point the barometer is lowest, and, in this hemis- 

 phere, the air is moving in the direction against watch 

 hands, or in accordance with the Buys Ballot's law just 

 explained, and the clouds and weather are distributed 

 according to known laws, which have been explained by 

 various authors. 



Now for the purposes of storm warning, in its simplest 

 conception, we have only to recognise the existence of these 

 depressions, and you must take it on my word that they 

 generally move over the earth's surface, and in these 

 latitudes usually advance from west to east. 



The rate of advance varies from, say, ten miles an hour 

 to as much as sixty or seventy miles an hour, a rate which 

 has been proved to have existed in certain storms crossing 

 the North Sea. 



When therefore one of these depressions appears on our 

 coasts, and not till then, can we venture to announce its 

 proximity by our warnings. 



We can only learn the fact of its existence from our 

 reporting stations, and these are represented on the map 

 which I exhibit. A glance at this will show how " few and 



