324 PHILOSOPHICAI. TRANSACTIONS. [anNO 1686. 



west, set in and blow for half the year, viz. from the beginning of December 

 till May ; and this monsoon is observed as far as the Molucca isles. 



3. That to the northward of 3° south latitude, over the whole Arabian or 

 Indian Sea, and Gulph of Bengal from Sumatra to the coast of Africa, there is 

 another monsoon, blowing from October to April, on the north-east points ; 

 but in the other half year, from April to October, on the opposite points of 

 S. W. and W. S. W. and that with rather more force than the other, accom- 

 panied with dark rainy weather ; whereas the north-east blows clear. It is like- 

 wise to be noted that the winds are not so constant, either in strength or direc- 

 tion, in the Gulph of Bengal, as they are in the Indian Sea, where a certain 

 steady gale scarcely ever fails. It is also remarkable, that the south-west winds 

 in these seas are generally more southerly on the African side, and more westerly 

 on the Indian. 



4. There is a tract of sea to the southward of the equator, subject to the 

 same changes of the winds, viz. near the African coast, between it and the 

 island Madagascar, and from thence northward, as far as the line ; wherein from 

 April to October there is found a constant fresh S.S.W. wind, which, as you go 

 more northerly, becomes still more and more westerly, so as to fall in with the 

 W. S. W. winds mentioned before, in those months of the year to be certain to 

 the northward of the equator. 



5. That to the eastward of Sumatra and Malacca, to the northward of the 

 line, and along the coast of Camboia and China, the monsoons blow north and 

 south, that is, the north-east winds are much northerly, and the south-west 

 much southerly. This constitution reaches to the eastward of the Philippine 

 isles, and as far north as Japan. The northern monsoon setting-in in these seas 

 in October or November, and the southern in May, blowing all the summer 

 months. Here it is to be noted, that the points of the compass from whence 

 the wind comes in these parts of the world, are not so fixed as in those lately 

 described, for the southerly will frequently pass a point or two to the eastward of 

 the south, and the northerly as much to the westward of the north; which seems 

 occasioned by the great quantity of land interspersed in these seas. 



6. That in the same meridians, but to the southward of the equator, being 

 that tract lying between Sumatra and Java to the west, and New Guinea to the 

 east, the same northerly and southerly monsoons are observed; but with this 

 difference, that the inclination of the northerly is towards the north-west, and 

 of the southerly towards the south-east. But the points from which the winds 

 blow are not more constant here than in the former, viz. variable 5 or 6 points. 

 Besides, the times of the change ot these winds are not the same as in the 

 Chinese seas, but about a month or 6 weeks later. 



