9G 



HYDROGRAPHY. 



west monsoon of the China Seas, the southeast monsoon prevails ; while 

 the northeast monsoon is the dry season, the northwest is the rainy ; 

 yet this is not the case throughout this sea, but more particularly 

 applicable to the weather coast, the leeward coast being generally 

 subject to great drought during the same periods ; and while the south- 

 west monsoon is the wet season of the China Seas, the southeast mon- 

 soon is the dry one of the Indian Ocean. The southwest monsoon is 

 supposed to be an extension of the southeast trades ; but this I think 

 there is great reason to doubt. We found the limits of the northwest 

 monsoon to extend farther than usual, to the 14th parallel of south 

 latitude ; and they extend to the northward of the equator as far even 

 as 5° north. The usual limits are within the latitude of 11° south 

 and the equator. 



The passages to and from China have been much shortened by the 

 enterprise of our ship-masters, and the superior class of ships that are 

 now built for this trade ; in consequence, these vessels pursue a much 

 more direct route, and instead of making the long detour recom- 

 mended by Horsburgh and others, for contrary monsoons, steer a 

 direct course towards the Straits of Sunda, and thence beat up the 

 China Seas against the monsoon ; indeed, so much difference is there 

 in the length of the passages, that a vessel may almost go and return 

 by the new route, before another could accomplish the distance to 

 China by the eastern passage. 



The passage home from the Straits of Sunda is a very simple naviga- 

 tion. When the northwest monsoon prevails, the course is to the south- 

 ward and westward, to reach the southeast trades as soon as possible : 

 these will generally be entered about the latitude of 10° or 12° south, 

 when the latitude in which they prevail with the greatest strength is 

 to be kept : this is generally between 12° and 20°. The parallel of 

 15° may be preserved, unless it is in the hurricane months, from 

 December to April, during which period it is advisable to give Mauri- 

 tius and Bourbon Islands a wider berth, experience having shown that 

 these storms take place more frequently and with more violence in 

 their neighborhood than elsewhere. These gales are represented 

 as more violent than those which occur in the West Indies, but the 

 accounts are probably somewhat exaggerated. The precautions advised 

 by Horsburgh, and all those who have written upon these storms, 

 or the typhoons of the China Seas, cause them to be looked forward 

 to with more anxiety than is necessary. The barometer gives timely 



