54 



HYDROGRAPHY. 



by compass is northwest I west. The depth of water on the bar will 

 be found to be 13 feet, and the passage never should be attempted but 

 at or nearly high water. The rise of the tide, at full and change, is 

 11 feet, and the current at the mouth of the river runs 5 knots; at 

 the anchorage in the roadstead it was 2 knots. The tide in the 

 river usually runs ebb 10 hours, and the flood 2 hours, but during the 

 freshets it runs ebb the whole time. Large quantities of sand and 

 mud are brought down, and on meeting with the ocean water, is de- 

 posited, forming extensive bars. 



The roadstead may be considered at all times dangerous, but par- 

 ticularly so during the winter months. From May till October, south- 

 east gales frequently blow, which are directly on shore, accompanied 

 by a heavy sea. They are preceded by a heavy swell and thick 

 weather, and are indicated by the barometer, which we found exceed- 

 ingly sensitive to change to the south of 30° latitude. The holding- 

 ground, composed of coarse sand, gravel, and shells, with clay, is good; 

 and there is no great difficulty in getting off shore, provided advan- 

 tage be taken of the flood tide, which sets to the windward, casting 

 on the starboard tack. 



The tide off the Rio Negro sets strong (the flood) to the south- 

 west 5 h, the ebb to the northeast 6h hours. This is opposite to what 

 Captain King gives it in his Patagonia directions, between Cape 

 Blanco and Cape Virgins. 



During the prevalence of northerly and westerly winds the weather 

 is fine and the sea smooth. 



Water may be obtained about a mile within Point de Maine, and 

 after settling is considered wholesome. Supplies may also be had, but 

 only in limited quantities ; the lack of industry of the inhabitants being 

 the cause of the scarcity, for the soil is capable of raising vegetables 

 and fruit in abundance. 



Vessels intending to visit this part of the coast would do well to 

 seek the fine harbor of San Antonio, at the head of the bay of San 

 Mathias, where supplies, I was informed, can be as readily obtained as 

 at the Rio Negro. It is but about 30 miles from the town of Paula 

 del Carmen. The charge on vessels in these ports is half a rial per 

 ton ; whale ships are admitted free for less than twenty days. 



