:;7s 



HYDROGRAPHY. 



Monsoon, in part, is diverted towards the centre of New Holland, 

 where a large rarefied area exists during the presence of the sun. 



The Southeast Monsoon appears in like manner linked with the 

 Southwest. That current of air extends from the Pacific Ocean, east 

 of New Holland, and flows to the westward in the Indian Ocean, side 

 by side with the Southeast Trade Wind. Although this wind is often 

 designated as the Southeast Monsoon, its direction is not at all times 

 from that quarter, but it frequently comes from east-northeast. 



The Monsoons which prevail in the Mozambique Channel, between 

 the Coast of Africa and the high land of Madagascar, lie between 

 latitude 30° south, extending across the Equator to the north, along 

 the east coast of Africa to Cape Jeddah, and half-way up the Red 

 Sea. These Monsoons pass under the Northwest Monsoon to the 

 west of longitude 50° ; the winds are light, and calms often take 

 place. The direction is from the north-northeast and south-south- 

 west, parallel with the coast of Africa. Their period is nearly coin- 

 cident with the Southwest and Northeast Monsoons, north of the 

 Equator, which causes them to be considered by some as an exten- 

 sion of the former ; but in reality they are separated by a region of 

 calms. They ought therefore to be viewed as distinct. 



Although the great Monsoons are confined to the Indian and 

 Pacific Oceans and China Seas, yet there are several of lesser note 

 and extent, which exist on the east and west coasts of North and 

 South America. That which claims particular interest from naviga- 

 tors, is on the coast of Brazil. It is experienced from the neighbor- 

 hood of Cape St. Roque to the Island of St. Catharine. Properly 

 speaking, however, these are not Monsoons, though they have been 

 classed and considered as such. They do not interchange their 

 direction periodically, like the others, but only veer through several 

 points of the compass. These changes on the coast of Brazil are 

 from the north-by-east round to the south, on the southern parts of 

 the coast. They show most conclusively that the currents of air are 

 induced towards the heated areas of the land, which become rarefied 

 from the action of the sun's heat upon the surface of South America. 



As the sun changes towards the south, in declination, the land of 

 South America becomes more and more heated. The air is drawn 

 towards these areas from the north and northeast, along the whole 

 ocean bordering on the east coast. It flows from the different points 

 of the compass towards the land ; in general, perpendicular to the 



