€h. IV. SOUTH AMERICA. 231 



every object on theotlier side of it : and the cautious 

 mariner forbears to make his way tliroiigh it, being 

 uncertain M'hether he shall meet with clearer weather, 

 as he approaches nearer to the coast. 



These winter fogs on the coast of Chili, seem to 

 be occasioned by the uorth winds ; they being ob- 

 served alw^ays to thicken when those winds blow, and 

 though the atmosphere be clear when the wind shifts 

 to that quarter, it is instantaneously filled with those 

 vapours ; which continue without any diminution, 

 till the S. winds set in, and have blown fresh for two 

 or three days successively. But as in winter they are 

 usually interrupted by the winds at N. W. and S. W. 

 these vapours, so inconvenient to commerce, are 

 seldom totally dispersed ; and it is a common phrase 

 among the mariners of these parts, that the N. is a 

 filthy wind on account of the disagreeable vapours, 

 with which it is loaded, and the S. is a cleanjy wind, 

 sweeping tliese nuisances from the coast and country, 

 and purifying the air. I call these winter fogs, as 

 they are equally common all along the coast from the 

 parallel of twenty to the equinox, where no N. winds 

 are known. And as I have already related of * Lima, 

 all the inhabitants of the coast live, during the winter, 

 in a perpetual fog. 



I shall conclude this chapter, with a table of the 

 variations of the needle observed in my second voyage, 

 in the frigate La Delivrance, from Callao, to Con- 

 ception Bay. 



