142 



MR JOHN ATTKEN ON 



which was over the Shetland Isles at 8 a. in., travelled to the east coast of Sweden by 

 6 p.m., a distance of 700 miles. During the following night the centre moved in an 

 E.N.E. direction at a considerable velocity, but at a slower rate than during the day, 

 as the barometric gradients at 6 p.m. would lead us to expect. 



Turn now to the chart for the 9th December 1897. Here it will be seen that 

 the barometric gradients are nearly equal all round, and strong winds are blowing 

 in all directions systematically round the centre. Now note the slow rate of progress. 

 This cyclone appeared on the N.W. of Scotland on the evening of the 8th December. 

 Next morning at 8 o'clock it was in the place shown in the chart, having travelled 

 a distance of 175 miles in the 14 hours. When this cyclone first appeared the 

 barometric gradient was steeper to the south than on any other side. This, no doubt, 

 was the cause of the advance of 170 miles during the night. It will, however, be seen 

 from the 6 p.m. chart, that the centre moved very little during the day, somewhere 

 about 75 miles, and the whole of the following night it was still over the same place, 

 having apparently become stationary, as it was still there on the morning of the 10th, 

 but the gradients were getting easier, the depression getting filled up. These two 

 cyclones were selected — out of many having similar histories — to illustrate the 

 point under discussion, and they were selected because they travelled over exactly 

 the same track, and at the same time of the year, so that we should only have the 

 question of the conditions shown by the shape of isobars to consider. 



To illustrate this point still further, the following table gives in brief the histories 

 of a few of the cyclones during the last two years. The table shows the date and 

 hour when the cyclone first appeared on the chart. Then there is given the situation 

 of the centre of the cyclone, followed by the character of the isobars or distribution 

 of gradient, and, lastly, the distance travelled in miles. 



1898. 



Date. 



Hour. 



Position of centre of Cyclone 



Isobars. 



Miles. 



Mar. 1 



2 



„ 3 



„ 4 



8 a.m. 

 6 p.m. 

 8 a.m. 

 6 p.m. 

 8 a.m. 

 6 p.m. 

 8 a.m. 



North-east of Scotland, .... 



North Sea, 



,, • . . . , 

 Denmark, ..... 



S. Baltic, ..'.'. 



N. Germany, ..... 





Not much difference. 



>> >j 

 „ filling up. 



)> >) 

 >> )> 



150 

 150 

 200 

 60 

 130 

 130 



Oct. 16 

 „ 17 

 „ 18 

 „ 19 



8 a.m. 

 6 p.m. 

 8 a.m. 

 6 p.m. 

 8 a.m. 

 6 p.m. 

 8 a.m. 

 6 p.m. 



Off entrance to English Channel. 

 >> )> 



>> )> 

 West of London, .... 

 Midland counties, .... 

 Border of Wales, .... 



N. Wales, 





Nearly equal. 

 )> >> 

 >) )> 



filling up. 



>> !> 



)> » 

 » )) 



100 

 90 

 50 



200 

 90 

 50 

 75 



