OYCLOXIC STORMS IN TEMPPJEATTRE LATITUDES 501 



country is included. Knllmer's map for storminess in Europe is given 

 in figure 4. Here it will be seen that there are three areas of great 

 storminess. One of these has its southern limit at the Hebrides Islands, 

 and extends northeastward beyond the Arctic Circle and to the north of 

 Europe. The second begins in southern England and extends northeast- 

 ward so as to cover Holland, Belgium, northern Germany, southern Swe- 

 den and ISTorway, the Baltic Sea, and southern Finland. The third is of 

 smaller size than the others. It is located in northern Italy and in the 

 Mediterranean area just west of that region. It is probable that the 

 intensity of the storminess here is exaggerated because of the sinuous 

 character of the tracks in this region. 



Cyclonic storms during the sun-spot cycle. — Before proceeding to a 

 discussion of these maps let us ascertain to what extent the actual amount 

 of storminess varies in harmony with the number of sun-spots. Let us 

 take first the American data, since they are more reliable than those from 

 Europe. The matter may be investigated in various ways. First, let us 

 take the three years of fewest sun-spots, wliich in most cases would be tlie 

 year of minimum spots and the years before and after, and let us com- 

 pare these with the succeeding three years of maximum spots. This 

 method is of especial interest, because these are the groups of 3'ears used 

 by Ivullmer in the highly significant maps which will shortly be presented. 

 An inspection of the sun-spot curve of figure 2 shows that since storm 

 records have been kept there have been three complete sun-spot cycles, all 

 of which have been of mild intensity compared with their predecessors. In 

 these we have three periods of minima and three of maxima. A com- 

 parison of the first two periods — the minimum of 1877-1879 with the 

 maximum of 1882-1884 — is of little value, since the records of these early 

 years are not highly reliable, and since for the minimum period the data 

 extend only to latitude 100° west. Coming to the next two periods — the 

 minimum of 1888-1890 compared with the maximum of 1892-1894 — we 

 find that during the maximum the storminess was greater than during 

 the minimum byj no less than 14.3 per cent of the mean for 30 years. 

 The storminess of the succeeding sun-spot maximum, 1905-1907, ex- 

 ceeded that of its preceding minimum, 1900-1902, by 1.4 per cent. 



Let us now consider the matter in another way. Let us compare the 

 complete sun-spot cycle from 1889 to 1900, inclusive, with the succeeding 

 one from 1901 to 1911. Each of these begins with a sun-spot minimum 

 and lasts until the year preceding the next minimum. The average sun- 

 •r^pot number for the 12 years of the first cycle was 38.8, and its stormi- 

 ness was 107.4 per cent of the average storminess for 30 years. The 

 average sun-spot number for the 11 years of the second cycle was 33.3 



