2b PRESIDENTIAL ADDRESS SECTION A. 



of the West of Europe is regulated by these two cyclones. Tliere 

 is no indication that a serious depression is forming- over the ocea?". 

 If a depression the centre of which would be over the Channel 

 within twelve hours were in the west, in ordinary circumstances, 

 all the barometers on the west coast would liava been falling 

 rajiidly during the night. The only one which showed a fall of 

 a quarter of an inch was that at \'alentia. The winds of the 

 West of Europe woidd. in ordinary circumstances, have Ijeen 

 already for some time regulated by the coming cyclone, and 

 would have ranged from south-west to east, being winds Ijelong- 

 ing to the front of a cyclone. On the contrary, they were 

 practically all different from the directions they ought to have, 

 as they mostly ranged from north to north-west. They were 

 therefore strongly abnormal with regard to the coming cyclone, 

 and there was nothing to indicate a coming storm, and no 

 meteorological ofifice gave warning; yet before night a terrific 

 storm had burst U])on the \\'est of Europe. 



Applying Guilbert's rules, we hnd that the fall of the 

 barometer at Valentia, which indicated the existence of a 

 d'epression over the Atlantic in the west, was sufificient to show 

 that a serious storm was likely to burst over Western Europe. 

 Eor this depression had in front of it nothing but winds tliat 

 were strongly abnormal ; it would, therefore, deej^en rapidly and 

 progress with great velocity as it found no resistance in front 

 of it. The track it would follow would be along the line of 

 junction over the two existing cyclones — the one off the Scan- 

 dinavian coast, the other over the Bay of Biscay — as that woukl 

 be a line of weakness. That this is a line of weakness is a clear 

 deduction from j\Ir. Guilbert's theory of the abnormal winds. 

 Along such a line the winds generally diverge from one another, 

 as one set belongs to one part of the cyclone A, and the other 

 set to the opposite part of the cyclone 15. and both sets of winds 

 will be abnormal in regard to the coming cyclone. On the map 

 of the 1 2th iNIarch this line of diverging winds was clearly 

 shown to pass from the entrance of the Channel through Xorth- 

 Eastern Erance into Belgium. This, therefore, is the line which 

 the centre of the coming cyclone would follow. In its course 

 it would absorb the two existing cyclones, and the depth of the 

 new depression would be, at least, ec[ual to the sum of the 

 depths of the component cyclones. This is exactly what hap- 

 pened. The cyclone passed over the Scilly Islands on the after- 

 noon of the I2th, and was over Brussels on the morning of the 

 13th. The barometer had dropped 25 mm. since the preceding 

 day. The velocity of its translation must have been over 1,000 

 miles in twenty-four hours, about three times the averagfe" 

 velocity; its violence was unusual, as winds of over sixty miles 

 an hour were registered in Paris during its j^rogress. The two 

 other depressions had been absorbed. 



This method has been carefullv discussed by some of the 

 leading meteorologists of the d^y. The j^rinciple of the normal 



