154 AUTUMN AND WINTER 



interrupted and complicated by the broken state of the 

 weather in some quarter. It is more difficult for an anti- 

 cyclone to maintain the perfect circulation of its winds than 

 for a cyclone ; for the currents rushing in to fill nature's 

 abhorred vacuum are strong, while an anticyclone is a system 

 of settled weather, in which the airs are usually light, and 

 often hardly noticeable. 



Cyclones in Britain travel at a rate varying from about ten 

 to seventy miles an hour ; and in those which move slowly the 

 regular incurvation of the wind from all quarters is often 

 well maintained. But the observations of the Meteorological 

 Office tend to show that many cyclones do not conform 

 fully to the typical cyclonic pattern. The sudden jump of 

 the wind from south-west to north-west, often experienced 

 as the centre of the cyclone passes, is itself enough to 

 suggest some sharp irregularity of structure. In a fast- 

 moving cyclone the speed and violence of the wind would 

 need to be tremendous, if it completed the full circular 

 course. We do not get such terrible hurricanes in this 

 country ; cyclones of this perfection of structure and corre- 

 sponding violence are reserved for tropical climates. Accord- 

 ing to the best opinion, the effective air currents in a 

 cyclone are three in number. First, there is a moist warm 

 southerly wind, on the front or east of the depression. In 

 the second place, there is a cold dry east wind crossing the 

 southerly current at a point about opposite to the centre ; 

 and the third current blows from the west, and comes in 

 on the south side. If the direction of these three currents 

 is set down as a diagram, it can be seen that they conform 

 to the general pattern of the cyclonic eddy. By the modi- 

 fication of their direction where they meet, the complete 

 cyclonic pattern can be formed from these three elements. 



The existence of these three main currents has been 



