Vol. XV. No. 370. 



THE AGRICULTURAL NEWS. 



211 



The reader will find it instructive to take a number of 

 points on the lowe.st section of the diagram, which corres- 

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

 of this wind (the arrows fly with the -n-ind), and (b) the rela- 

 tive position of the centre. 



Reverting 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 



.c^t 



C.N,E J-_ 





■ IN HICK LATITUDCS; 



Velocily aJoD^ trauc. - y9.' 



20 10.30 miles per hour ,J>'> " ^y^ ^ ^- 



tS' 'T't- — 



o^ "111, 'mW^c\\ \ \- ^ '■ •? 



// , ■ "o 



■ /5 ".Ac, 



IN-MIDDLE LATITUDES 

 STORM RCCURVIHG: 



Velocity- along track, 

 5 Co 10 xuilps per bour. 



\a.SX '^'''*- -Hnrricanp.g rficinrre about 

 tile foUtrwjng latitTidofl ■ 

 't Juae and Oct.. lat. 20'to 235N 



/. July ajul Sept.. lat. 2Vto 29' N 



/, [o August, lat 30'to3TN. 



KS/ 



MN LOW LATITUOE.S 



" yelocity along tract 

 ^bout 17 xniles pM hour 



Nt/A / ''^ -- ..^re-'V, 



motion; this latter is represented in the hurricane by the 

 movement of the revolving storm from one place to another. 

 Usually West Indian hurricanes approach 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 finally eastward, so that the storms pass out 

 into the North Atlantic. 



This progressive motion across the West Indian islands 

 is comparatively slow, ranging from about 7 to 14 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 

 towards him, or is passing on the north or on the south side 

 of him. 



If the direction of this wind remains fairl}' constant in- 

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

 centre is directly approaching. Conversely, when the wind 

 direction remains SE, ESE and S, the centre is moving: 

 directly away. 



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

 E and E.SE, the centre is passing on the south side of the 

 observer. 



^^'hen the directiijn changes from XW to WXW, S 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. Fromi 

 these an observer can anticipate fairly exactly what may 

 be expected to happen, and — a matter of great importance — ■ 

 he is able to recognize when the centre has passed and the 

 storm may be expected to begin 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 pirticular place the- 

 direction of the wind suddenly changes, and the wind after 

 its passing begins to blow violently from exactly the oppo- 

 site direction from that from which it blew before: this is 

 a feature of considerable importance in West Indian hurri- 

 canes. The barometer falls rapidly as one gets nearer and 

 nearer the centre, so 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 direction of the 

 wind afford clear indications of the line along which the 

 centre is travelling. 



In judging the direction of the wind it is best to note 

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

 better than observing weathercocks or flags. 



It is worth noting that in the West Indies — the rule does 

 not apply elsewhere — in describing the direction of the wind, 

 when one employs the terra south, the centre has passed audi 

 conditionsi may be expected to improve. This may be con- 

 firmed by noting the position of the centre in relation to such 

 winds as SSW or SE, or any in which the term south occurs. 



On the other hand, the dangerous position is indicated' 

 by those wines which involve the use of the term north, as- 

 may be seen by noting what is implied by such winds as- 

 NNE, or N or NE. 



The first indication of an approaching storm is frequently 

 a heavy swell, breaking in heavy surf along the shore : 

 these waves come from the direction of the centre of the- 

 approaching storm. They may be noticed many hours, 

 .sometimes a day or two, before the storm passes. 



The next indication is usually some disturbance and' 

 unusual movement amongst the higher clouds, coupled witk 

 unusual light, often a coppery glare, at sunrise or sunset,, 

 particularly the latter: the wind is then unusually irregular 

 an:l putty, and the atmosphere moist and oppressive. The 

 next indication is a fall in the barometer, and then the 

 observer may feel certain that a cyclone is in existence. 



It is worth noting that cyclones may, and do, exist ia 

 which the wind is rotating with only moderate velocity: they 

 present all the characters here referred to, save that not 

 having violent winds they do no damage: it is only when the- 

 wind blows violently that a cyclone becomes a hurricane. 



These facts are readily grasped and appreciateii;. 

 a knowledge of them is of great service to West Indians, 

 enabling them to take such precautions as are possible to- 

 protect themselves and their property from approaching 

 storms, and relieving their minds of great anxiety when they 

 are able to recognize that a threatened storm has passed. 



