18 Hon. Ralph Abercroroby. Relation between 



and forms eddies and vortices that break the continuity of the stream 

 lines. As a matter of observation, nothing is commoner than to see 

 a gust of wind blow down from a mountain on to a lake, and then 

 ricochet up again. 



The wind round a typhoon is always an in-going spiral. The 

 incurvature is usually strong, but differs in every segment, not only 

 in each cyclone, but even in the same cyclone at different periods of 

 its existence. So much is this the case, that it seems impossible to 

 give any mean incurvature for the Philippines. This is curious, for 

 farther north the variation of incurvature seems more constant. 



The motion of the lower nimbus is always more nearly parallel to 

 the isobars, and therefore more nearly eight points from the bearing 

 of the centre, than the surface winds. This is identical with the 

 experience of European cyclones, and has an important bearing on 

 the rules for handling ships at sea, though that question cannot be 

 discussed here. 



The observations of Padre Faura on the variation in the destruc- 

 tive effects of the wind in different parts of a typhoon, and the manner 

 in which he uses this knowledge in forecasting, are so important and 

 so unknown in this country, that the author proposes to devote one or 

 two paragraphs to their consideration. 



Faura finds that the position of the strongest winds relatively to the 

 centre of the cyclone varies not only in every typhoon, but in the same 

 one ; and also that for the same velocity, the wind will unroof houses 

 in one cyclone, but do comparatively little damage in another. He 

 assumes that the unroofing wind is blowing slightly upwards, and the 

 wind that does little damage moves horizontally or slightly down- 

 wards. 



If then he can find evidence that the wind is rising up in front of 

 a typhoon, he can be pretty certain that it will descend in rear; and 

 therefore can and does forecast that the wind in that portion of the 

 storm will be less destructive. 



From all this, he has been led to the conception that the axis of a 

 typhoon is inclined, and that it nutates during the progress of the 

 vortex. 



For instance, in the typhoon of October 20th, 1882 — figured below 

 — he believed that the wind in front was certainly rising and low ; a 

 beam lying near the sea, at a distance of 300 — 400 metres, was thrown 

 upon the observatory (height 34 metres) and destroyed the Beckley's 

 anemometer, while the roofs of many houses were pulled off. From 

 this Faura concluded that the rear would not have the same force as the 

 front, because the wind would be high and falling ; and he published 

 a notice at noon on the 20th — " The S.W. winds will be very short." — 

 This prognostication was justified by the event. 



The contrary took place in the typhoon which followed a few days 



