138 



NATURE 



[Dec. 9, 1886 



does not experience any strong wind or bad weather till within 

 a hundred miles or so of the centre, and a^ the typhoons are 

 most violent in that locality, it is very important to look out for 

 the premonitory signs referred to in the (irst section of this 

 article, taking into account that the dimensions of a typhoon 

 are so small there. On the other hand, they move at so slow a 

 rate that you may run away from them if you are aware of the 

 danger in time, so much more as you maybe sure that a typhoon 

 in that locality is directing its course to somewhere about west- 

 north-west or north-west, and most likely in the first-named 

 direction. So it is better to get to the eastward of it. Nearer 

 the Philippine Archipelago the typhoons usually take a more 

 northerly cour.^e, moving north-west or north-north-westward. 

 But frequently they continue their course west-north-westward 

 and cross the islands to enter the China Sea. In spring and 

 autumn they have even been found to move westward and turn 

 south-westward after entering the China Sea. But when you 

 are east of the Philippines you should try to get your ship south- 

 east of the typhoon by crossing the path behind the centre, if 

 possible. If you are going northwards, you will then benefit by 

 the fresh south or south-west breezes, taking care not to approach 

 too near to the typhoon, whose progressive motion may not 

 be more than six miles an hour. You will probably have squally 

 and wet weather. 



When all the paths of the typhoons that have been investigated 

 by the writer in the cour-e of the last three years are laid down 

 on a map of the Far East, the picture looks much like a fan, 

 the paths, with a few stray exceptions, radiating from the locality 

 referred to above, and running in all directions between west and 

 north, but most of them at first westward and then north-west- 

 ward. In a higher latitude they generally recurve and pass off to 

 the north-east, after first, of course, having turned northwards. 

 Every typhoon does not recurve ; in fact, as stated above, some 

 of them finally disappear in the China .Sea after turning to the 

 south-west. The others recurve betwen 20° and 40° latitude, and 

 115° and 130° longitude. The Middle Dog Lighthouse is situated 

 in the centre of the region of recurvature. 



The normal path is therefore, roughly speaking, a parabola, 

 whose axis lies from east to west, and whose apex is turned 

 westward and lies within the- region indicated above. But 

 each path individually is anything but a regular parabola, and 

 the deviations are evidently due to the influence of the coast-line 

 of the nininland of Asia and to the mountainous islands (espe- 

 cially the high mountains of Formos.a) as well as to the prevailing 

 winds. For there is no doubt that the progression of a typhoon 

 is the effect of the wind prevailing at the time, not necessarily at 

 the surface of the earth, but at a somewhat higher level in the 

 almosphere, which .agrees with the direction of the clouds, that 

 have, as explained in the first section of this article, been 

 found to move nearly straight towards the centre in the posterior 

 semicircle. If, however, the wind at the surface of the earth is 

 strong, it is at limes plainly seen to blow the typhoon before it. 

 The typhoons do not appear to move south-westward in the China 

 Sea except when the north-east monsoon is strong, and in the 

 summer of 1SS5, when the south-west monsoon was strong, most 

 of the typhoons moved northwards while yet to the east of 

 Formosa. This is then the reason why the typhoons depend 

 upon the season of the year. They are likewise deflected from 

 their previous path when exposed to strong winds blowing 

 out of open channels, such as the Formosa or Corea Channels, 

 in w hich case the speed of their progress is sometimes abruptly 

 increased. 



Tlie average rate of progress of the centre of a typhoon in 

 11° latitude is 5 miles an hour. In 13° it is 6^, in 15° it is 8, in 

 20° it is 9, in 25° it is 11, in 30' it is J4, and in 32^° latitude it is 

 1 7 miles an h-'ur. The rate of progress does not vary perceptibly 

 in case of typhoons south of 13° latitude, .so it is well for masters 

 of vessels to know this, but it is more variable the farther north 

 you go. In 32j° latitude it ranges between 6 and 36 miles an 

 hour, so that you cannot at all be sure that a typhoon, which 

 you may happen to be near, will travel at anything like the 

 average rate of progress in that latitude. 



In " Observaiions and Researches made at the Hong Kong 

 Observatory in the year 18S4,'' the writer suggested the division 

 of typhoons into four cla ses according to the paths which they 

 usually follow. Of course abnormal instances, such as for 

 instance are presented by the typhoons that originate in the 

 China Sea, occur occasionally in China as well as elsewhere, but 

 they are comparatively rare. 



Typhoons of the first class occur at the beginning and the end 



of the typhoon season. Tliey cross the China Sea and tr.avel 

 either in a west-north-westerly direction from the neighbourhood 

 of Luzon towards Tonquin, passing south of or crossing the 

 Island of Hainan, or, if pressure is high over Annani, they 

 travel first westward and subsequently south-westward. They 

 can generally be followed for between five and six days. 



Typhoons of the second class are the most frecjuently encoun- 

 tered, and their paths can be traced farthest. They generally 

 travel north-westward while in the neighbourhood of Luzon, and 

 either strike the coast of China south of the Formosa Channel, 

 in which case they as a rule abruptly lose the character of a 

 tropical hurricane, recurve in the interior of China, re-enter the 

 sea somewhere between Shanghai and Chefoo (thereby regain- 

 ing some of their past violence), pass across or near to Corea, 

 .and are finally lost sight of in their motion towards about east- 

 north-east ; or they pass up through the Formosa Channel, 

 recurve towards north-e.a3t, and pass along the coasts of Japan ; 

 or they may strike the coast of China north of Formosa. 

 Typhoons following the latter path originate further east of the 

 Philippines than the others. They either continue their motion 

 north-westward, in which case they are soon lost, or recurve and 

 pass north-eastward near Corea. Typhoons of the second class 

 occur from June to September inclusive, but are most common 

 in .'Vugust and September. It appears that a third of the 

 typhoons belong to this class. They can be followed on an 

 average 7 days, or rather between 5 and 12 day--. 



Typhoons of the third class are probably the most numerous 

 of all, but are not encountered so frequently as the typhoons of 

 the second cl.iss, .and therefore the existence of a typhoon of this 

 class is sometimes only suspected, although it of course infiu- 

 ences the weather along the eastern coast of China through the 

 fine weather area with which it is surrounded. They pass to the 

 east of Formosa, travelling northwards. After recurving, they 

 generally pass near Japan, but sometimes a typhoon of this class 

 continues to move north-north-westward and does not recurve 

 till west of Corea. They prevail in the same season as typh.jons 

 of the second class, and may be traced on an average during 7 

 days, or more correctly between 3 and 12 days. A typhoon 

 of this class frequently follows after one of the second class. It 

 is a well-known fact that depressions are attracted towards places 

 which have just been traversed by a depression. 



Typhoons of the fourth class pass south of Luzon, travelling 

 westward, or first in this direction and then .south-westward. 

 They occur at the beginning and the end of the typhoon season, 

 while the north-east monsoon is strong, namely in April and 

 late in autumn, but are very rare. They are said to be more 

 violent in autumn than in spring. Existing in so low a latitude, 

 their dimensions are, of course, very limited. The writer 

 has not been able to follow them for more than a day or 

 two. 



The number of typhoons that are known to have occurred in 

 each month of the year, expressed in percentages of the total num- 

 ber of typhoons, is as follows : — ^January 2, February o, March 2, 

 .\pril 2, .May 5, June 5, July 10, .\ugust 19, September 27, Octo- 

 ber 16, November 8, and December 3. These figures prove 

 that typhoons are most frequent during the month of Septem- 

 ber, but they also show that, strictly speaking, there scarcely 

 exists a well-marked typhoon season. On an average there are 

 15 typhoons every year, but typhoons in different years exhibit 

 some variations. 



IV. The writer on his arrival in the colony in 18S3 found 

 that meteorological observations were received from a few of the 

 Treaty ports, &c., and were published in the local papers ; and 

 seeing that these returns would only have to be corrected and 

 reduced, as well as slightly extended, in order to be of great 

 v.alue to the shipping, he took upon himself to effect this. Sub- 

 sequently, as the official work of the Observatory was fully 

 started, he would have had to give up this purpose had not the 

 Government decided to support it. Thus originated the China 

 Cotiit Ak'eorological Register, which is published daily from 

 here. It contains, at present, observations of the princip.il 

 meteorological elements, which are received through the co- 

 operation of the great telegraph companies from Manilla, Bolinao 

 (Luzon), Haiphong, Hong Kong, Amoy, Foochow, Shanghai, 

 N.agas.aki, .and Vladivo tock, but the number of the stations 

 might with advantage be extended. It gives also information 

 about the weather prevailing in the Far East, and more or less 

 rough intimations concerning such typhoons as happen to be 

 indicated by the telegraphic returns, as well as by local observa- 

 tions. Subsequently more or less extensive monthly meteoro- 



