Vol. XVI. No. 396. 



THE AGRICULTURAL NEWS 



199 



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

 the centre is at right angles to this line of movement. 

 Consequently in a hurricane, if the observer stands facing 

 the wind, the centre of the storm is on his right-hand. He 

 can trace the movement of the centre by noting the change 

 in ihe direction from which the wind blows. 



The reader will find it instructive to take a number of 

 points on the lowest section of the diagram, which corre.s- 

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

 of this wind (the arrows fly with the wind), 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 band, move from 

 thi.s; there will then be two motions; a spin and a projrressive 

 motion: this latter is represented in the hurricane by the 

 movement of the revolving storm from one place to another. 

 Usually AVest 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 change?, 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 fairly constant in 

 a direction NNE or X or XX W, 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 EXE. 

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

 observer. 



When the direction 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: thej' 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 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 expecttd 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 particular place the 

 direction of the wind suddenly changes, and the wind after 

 its passing begins to blow violently from exactly the opposite 

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

 feature of considerable importance in West Indian hurricanes. 

 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 flag.--. 



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 

 and conditions may be expected to improve. This may be 

 confirmed by noting the position of the centre in relation to 



such winds a.s SSW or SE, or any in which the term south 

 occurs 



On the other hand, the dangerous position is indicated 

 by those winds which involve the use of the term north, as 

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

 XXE, or X or XE, " 



The first indication of an approichin ,' 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 with 

 unusual liijht, ofien a coppery glare, at sunrise or sunset, 

 particularly the latter: the wind is then unusually irregular 

 and putfy, and the atmosphere moist and oppressive. The 

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

 observer may feel certain that a cyclone is in existence. 



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

 which the wind is rotitting with only moderate velocity: they 

 present all the characters here referred to, save that not 

 having violent winds they do not damage: it is only when the 

 wind blows violently that a cyclone becomes a hurricane. 



These facts are readily gra-sped and appreciated; 

 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 lelieving their minds of great anxiety when thej' 

 are able to recognize that a threatened storm has passed. 



SWEET POTATOES IN ENGLAND. 



In reporting upon some sweet potatoes recently sent by 

 the .Jamaica Agricultural Society, through the West India 

 Committee, to the Food Committee of the Ro3'al Society, 

 the Secretary wrote, as appears in the West India Committee 

 Circular of May 17. 1917: 'The sweet potatoes which 

 you were good enough to send were tried by various members 

 of the Committee, and the unanimous conclusion was that 

 they would prove a very acceptable foodstuff, and one 

 which people would readily get used to. But I regret to 

 say there are two difficulties in the way of getting supplies 

 to this country. The first is the bad keeping qualities of 

 the sweet potato. Within a fortnight of their arrival here, 

 the greater number of them had gone rotten. This was not 

 due to careless storage. The crates, when they were 

 received, were simply opened and put in a cool place. A 

 further difficulty, in view of the small tonnage available, 

 is the large water content — namely, •5-5 per cent." Apart 

 from other considerations the increase in the price of food- 

 stuffs in the West Indies, which has been accentuated since 

 the entry of the United States into the war, makes it most 

 improbable that there will be any surplus for exportation. 



It is not generally known that the sweet potato (Batatas 

 cdalis), which is probably of American origin, was introduced 

 by Gerard into England from Spain in 1597, about the same 

 time as the potato was introduced from Virginia. On 

 account of the great yield of the sweet potato experiments 

 have been made to grow it in temperate climates. Sweet 

 potatoes are grown as a field crop in Algeria, Spain aud the 

 Canaries, whence they are sometimes imported in small 

 quantities into the United Kingdom, where they are offered 

 for sale in the best-rate vegetable shops. Their cultivation 

 with the aid of artificial heat has been attempted in Paris 

 without, however, much success, and it is useless to try to grow 

 them as a garden crop in England. 



