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THE AGRICULTURAL NEWS. 



JCNB 14, 1919. 



HURRICANE WARNINGS. 



The approach of the hurricane season makes it <!esirable 

 tortpubli.sh thef' llowinf; information concerning their nature, 

 and the signu which indicate the approach of these storms in 

 the West Indie-s. 



It is urged that instruction in connexion with this 

 subject should be given in all secondary schools in the 

 Windward and Leeward Islands, and {K)ssibly in the primary 

 schools as well. One or two lessons given in each year 

 immediately before the hurricane season should prov? of real 

 MrfiM. 



It is first desirable to point out the nature of a hurricane 

 and itii path of transition. With this object the diagrams 

 below have been leproduced, having first appeared in this 

 Journal in connexion with an editorial on hurricanes (see 

 Agriiulturat Xtwi. Vol. VIII, p. 209). 



The lowest figure represents the storm during its passage 

 through the West Indian islands, before it takes a sweep 

 round to the north or West of Cuba, into the North Atlantic 

 (lop figure). 



. (■ nkCM lATITUDCS 

 3e \^ 30 nu^B far hA«# 



(N middle: LATTITTS 



STORM RECu."iV;:-:o- 



Veloa^ along ti-f.cr 

 5 to 10 milpB p»i- :._-.^ 



'■'y I ' I A« foiltmlng latitadoB ■ 



'. / f. I June and Oct.. lat 20' to Iv: ;< 



' '. July ajid Sept , lat 27'to 29' \i 



I. ]• Augti^.lat 30'to .IT N. 



warn bATiTMOM: 





£x\\W^«;, 









->'a 





"vtr 



Toe triotion of rotation, and the motion of translation 

 may \v well understofxi by spinning a t<^)p and giving it 

 a counter-clock rotation. It will be f ten that while the rotation 

 may be very rapid round the centre, the top itself may remain 

 in one upot. This rotation corresponds with the violent wind 

 <)f the hurricane. By noting the direction in which any part 

 of the (edge of the spinning top is moving in relaiion 



to the centre, it will be obvious that the position of the 

 centre IS at right angles to this line of movement. Conse- 

 quently in a hurricane, if the observer stands facing the 

 wind, the centre of the storm is on his ri^ht-hand. He 

 can trace the movement of the centre by noting the change 

 in the airection from which the wind blows. 



The reader will find it instructive to take a number of 

 points on the lowi-st section of the diagram which corres- 

 ponds with West Indian c nditions, and note (a) the direction 

 of this wind (the srrows Hy with the wind), and (b) the rela- 

 tive position of the centre. 



H«Terting to the spinning top, while it may remain 

 spinning on one spot, it may, on the other hand, move from 

 this; there will then be two motions: a spin and a progressive 

 motion; this latter is represented in the hurricane by the 

 movement o( the revolving storm from one place to another. 

 Usually West Indian hurricanes ajiproach the islands from 

 the Atlantic, that is, from East or ESE, and travel 

 towards Cuba and the American coast, where the path curves 

 northward and tinally ea.stward, to that the storms pass out 

 into the north Atlantic. 



This progressive motion across tho West Indian islands 

 is comparatively slow, ranging from about 7 to 1 4 miles an 

 hour. 



An observer, therefore, knowing the general trend of the 

 hurricane's path may. by observing the direction of the wind 

 and its changes, form a very good idea of his position as 

 regards the centre, and whether the centre is coming directly 

 lowaids him or is passing on the north or on the .south side 

 of him. 



If the direction of this wind remains fairly constant in 

 a direction NNK, or N, or NNW, the probability is that the 

 centre is directly aproaching. Conversely when the wind 

 direction remains !SE, SSE, and S, the centre is moving 

 directly away. 



Where the motion of the wind changes from NE to ENE, 

 E and ESE, the centre is passing on the south side of the 

 ob.server. 



When the direction changes from NW to WNW, W and 

 WSW, the centre is passing to the north of the observer 



These rules apply in the West Indies only: they should 

 be checked by making trial observations on the lowest figure 

 in the diagram until the matter is clearly understood. From 

 these an observer can anticipate fairly exactly what i.nay 



be ex| ecled to happen, and — a matter of great importance 



he is able to recognize when the centre lias passed, and the 

 slurm may Le e.xptctid tu Le^in to abate. 



The violence of the wind increases as one approaches 

 the centre; at the centre itself there is an area of calm. 

 When this centre passes over any jiarticular place, the 

 direction of the wind suddenly changes, and the wind after 

 its pa.ssiog begins to blow violently from exactly the opposite 

 diriction from that from which it blew before: this is a 

 feature of considerable importance in West Indian .'iiirricanes. 

 The barometer falls rapidly as one gets nearer and nearer the 

 centre, fo that the barometer affords a means of marking the 

 approach of the centre, and the probable distance that it is 

 away, while the changes in the directions of the wind aflord 

 clear indications of the line along which the centre i« 

 travelling. 



Jn judging the direction of I lie wind it is best to note the 

 direction in which the lower clouds are moving: this is better 

 than observing weathercocks (ir flags. 



It is worth noting that in the We.st Indies — the rule 

 dots not ap|ily elsewhere — in describing the direction of the 

 wind, when one employs the term .south, the centre has passed 

 and conditions may be expectrvi to improve. This may b« 



