a little beyond which, stands the town of St. Catherina. From hence to the south end of the island, the channel will only admit small vessels out to sea.

The proper passage into the harbour is round the north end of the island, between it and the Isle Alvoreda, distant about two leagues to the northward; but a ship may pass occasionally betwixt this isle and the other small isles to the N. W. of it, or between the latter and the main if necessary, the depths being from 8 to 12 fathoms among those isles. Having rounded the north end of the island, steer to the S. W. and southward, keeping about midchannel between St. Catherina and the main, and anchor under the small Isle Atomeri, situated near the latter.

Atomeri Isle, is in lat. 27° 22' S, observed by Dr. Horner, astronomer to the Russian voyage of circumnavigation, under the direction of my friend, Captain Krusenstern, who made the variation here 7° 50′ E. in 1803.

Here ships are well supplied with fruits, vegetables, and refreshments of various kinds, but the prices are not very low. Several small isles line the shores of St. Catherina on both sides, those off the south end extending about three leagues to seaward; and the soundings increase to 65 or 70 fathoms about 10 leagues east of St. Catherina.

Although neither the Spanish, or Portuguese charts, nor those published hitherto in this country, mark any soundings between Rio Janeiro and Rio de la Plata, yet every part of this coast seems to be fronted by soundings, in some places stretching to a considerable distance off shore.

From the island St. Catherina to Morro St. Marta, the coast extends about 20 leagues S. S. W.; from hence to Cape St. Mary, at the entrance of Rio de La Plata, the direction of the coast is generally about S. W.: and in this space it has no safe harbours for large ships, but the shore in most places may be approached to a moderate distance with safety.

Instructions and Observations for Navigating the Rio de la Plata, or River Plate.

By Captain Heywood of the Royal Navy.

AT RIO DE LA PLATA ENTRANCE, the prevailing winds during the summer months, from September to March, are northeasterly, with tolerably clear weather over head, but a dense atmosphere near the horizon. These winds haul gradually to the eastward as you advance up the river; and about the full and change of the moon, strong breezes from southeastward are common at this season, accompanied with rain

and foul weather. At Buenos Ayres, during the summer months, the S. E. winds are generally fresh in the day-time, hauling round to northward in the night.

During the winter months, from March to September, the prevailing winds at the entrance of the Plata are S. W. or more westerly but up the river, more generally from the northward than the southward of west.

In the winter season is the best weather at Buenos Ayres, for the winds being chiefly from N. W. to S. W., the water is smooth, and the communication can be kept up between the shore and the shipping with more facility. The weather is sometimes foggy, but fogs are most common in the months of July, August, and September, prevailing more at the entrance of the river, and as far up as the S. E. tail of the Ortiz, than above these banks.

As it cannot be said regular tides exist in the Plata, but currents as uncertain in their duration as they are irregular in their rate and direction, no certain allowance can be made for them; therefore a ground log should be used, to find the course made good and distance run.

The tides, when the weather is settled, and the winds moderate, seldom rise or fall more than 5 or 6 feet; though at Buenos Ayres, 8 miles distant from the city, we found in the Nereus, when the winds were strong at N. W., sometimes only fifteen feet water; while with strong breezes from E. S. E. to S. S. W., the depth was upwards of five fathoms: but, except on such extraordinary occasions, we had between 17 and 22 feet water.*

The river Plata has many singularities; which arise, perhaps, from its formation being different from any other known river. Its entrance being very wide and shallow, it is affected by every change of wind in a remarkable manner; that a shift of wind may be predicted almost to a certainty, by observing carefully the state of the barometer, and the set of the currents, which usually shift before the wind. In calm weather, the currents are generally very weak, setting up and down the river alternately, and nearly as regular as tides. When the winds are variable the currents are equally so; and I have known the ship to be current rode four different ways in less than six hours. When the current comes in from eastward along the north bank of the Plata, a northeasterly wind may generally be expected to follow, and at the same time (should the wind have been previously to the S. E.) the barometer will fall a little;

* I have heard, however, some marvellous stories, of the river having been almost dried up, across from Buenos Ayres to Colonia, during heavy westerly gales.

but much more, if the transition be quick from southwest, without stopping in the southeastern quarter.

When the wind continues in the northeast quarter, proportionate to its strength, the mercury is more depressed than with any other wind, and then there is usually a set into the river on the north bank, and out on the opposite bank. Indeed, whilst the winds are between N. E. and S. S. E. the current generally runs to the westward, past Monte Video, though without much augmenting the depth of water off that place, but filling the river above the banks.

Winds between N. N. E. and W. N. W. make the water lowest; the outset being then strongest along the south bank of the river, past the points del Indio and Memoria; but very inconsiderable along the north bank.

Prior to a southwest gale, or Pampero, the weather is usually very unsettled, with unsteady and variable winds in the north and northwest quarters; preceded by a considerable fall of the mercury, though it usually rises a little again before the wind shifts to the southwest; and often continues to rise, even though the wind may increase from that quarter. Before these set in at Buenos Ayres, the current runs up and fills the river unusually high; at the same time, as strong an outset is experienced along the north bank, which continues whilst the winds are strongest from W. S. W. to south, seeming to prove, that these winds force up from the southward, a large accumulated body of water past Cape Antonio, which can only find a passage out again by the north shore, where they increase the depth of water, as well as up the river, and particularly in the shallow harbour of Monte Video. Whilst these S. W. winds blow, the air is cold, and the atmosphere clear and elastic, in a degree rarely to be met with in any other part of the world. They are generally succeeded by some days of fine serene weather; the wind continuing moderate from the southward, or varying to the eastward.

I have never known the velocity of the tide or current in any part of the river, to exceed four knots per hour; although it is reported, sometimes to have run six or seven miles an hour!

As the winds outside the river Plata, and particularly about Cape St. Mary, are most frequent from the northeastward and northward, except when the southeast summer, and southwest winter gales blow about the times of new and full moon, I consider it most adviseable, for ships bound into the river, to get in with the land about the latitude of that cape, which is 349 40' S., and its long. 53o 54' W. of Greenwich, or 2° 09′ E. of Monte Video.

In lat. 33° S. the bank of soundings extends off the land full 36 leagues, where the depth of water in long. 50° 20′ W. is 94

fathoms, and the quality of the bottom dark olive coloured mud, or ouze, as it is all along the outer verge of the bank. In lat. 34° S. and 30 leagues from the land, the bank is steep; and the soundings decrease quickly in standing to the westward, to 25 fathoms 20 leagues from land.

In lat. 34° 20′ S. long. 51° 50′ W., or about 30 leagues east of the Great Castellos Rock, the depth is 63 or 64 fathoms dark mud. In standing for the land, between the Great Castellos and Cape St. Mary, the water shoals in a short distance from 60 to 25 fathoms; and the quality of the bottom changes to sand, which grows coarser as you approach the coast; and as far as 7 miles off shore, is intermixed with shell. This bottom is found only in, to the northward of the latitude of Cape St. Mary, except very close in with this cape.

To the southward of 34° 40′ S. the bottom is chiefly mud, intermixed with fine 'sand or gravel; and if a ship happen to be set to the southward of Cape St. Mary, as she hauls in for the land, yet keeps to the northward of Isle Lobos, she will get out of fine sand, into dark mud; which is the quality of the bottom (chiefly) between Cape St. Mary and Lobos; as well as 8 or 9 leagues to the eastward of that island; and the depth of water between them, is generally 26 to 20 fathoms.

In lat. 35° S. long. 52° W., or 42 leagues true east of Lobos, there are about 90 fathoms water, dark sandy bottom; from thence, the bank of soundings takes a S. W. direction. East of Lobos 27 leagues, the depth is 25 fathoms; and in steering in, on its parallel, the same depth nearly continues till very close to that island. But if set a little to the southward of Lobos, the water will shoal even to 10 fathoms perhaps, on a hard sandy or gravelly ridge that extends all the way from the English Bank, in its parallel as far as long. 52° 30′ W.; or full 18 leagues to the eastward of the meridian of Lobos.

Thus, the approach to this river cannot be considered dangerous, if proper care be taken in navigating, and due attention paid to the lead, and the course steered.

Captain Bouverie, gives the following remarks :

"CAPE ST. MARY,* is a low point, fronted by rocks, and

* Remarks of Captain John Butler, of ship Thalia, of Philadelphia, on the entrance of the River Plate.

"There appears to be a serious error in Captain Bouverie's description of Cape St. Mary's. He has described it as a low point, fronted with rocks, with a house about 6 miles to the north of it, a row of trees to the north of the house, and about one mile south of the house, a bluff point with a few rocks in front of it close to the shore. Now there is no point of land between Rio Grande and the Island of Lobos, that answers this description, but the point of Laguna Blanca, on which stands Estancia Ignez of the Spanish charts, which evidently is the house and trees described by Captain Bouverie; and as the difference between the latitude of the true Cape St. Mary's, and the point of the Laguna Blanca, is only eight miles, ships coming in from sea, uncertain of their lon

1

"the direction of the coast to the westward of this Cape, "becomes more westerly than at any other part northward of "it. About 6 miles north of it is a house, with a row of trees "northward of the house, (probably a fence of high prickly " pear-bushes,) which is very remarkable.

"About a mile south of the house, is a bluff point, with a few "rocks at the foot, which is remarkable, being different from "the rest of the coast, the general character of which is a sandy "beach. You cannot fail knowing the cape by these marks, "when running down the coast near it but at a considerable "distance off, you will not perceive them.*

:

"To the northward of the Cape, between it and Palma, you "have 10 or 11 fathoms at a little distance from the shore.

"Ships generally make the land with N. or N. E. winds; "therefore it is best to keep in the latitude of the cape or a little "to the northward of it, till you get soundings, as the current "sets to the S. W.; but do not make the land north of the cape; "for although there seems no real danger, yet the water in many places is shoal a long way off the land, and would alarm strangers.

About

"In lat. 33° 27' S. long. 52° 09′ W. is a shoal where we "found 9 fathoms water; which is probably a ridge, running "in that parallel of latitude all the way to the shore. In lat. "34° S. is some tolerably high land, on which is a Spanish for"tress, called Fort Teresa; being a square, with bastions at "the angles, and stands about a mile from the beach. "6 leagues N. N. E. from it, is a mark set up, as the termination "of the Spanish territories. Being in the latitude of Cape St. "Mary, and having got ground in 28 or 30 fathoms water, fine "sand and shells, you may reckon yourself 20 leagues off shore: "with from 15 to 20 fathoms, sand and clay mixed, you are "not far off the land. When you have not seen the land before "night, be sure to keep to the northward of the cape by your "reckoning, as the current sets to the southward, with north "and N. E. winds: with S. and S. W. winds, it runs strong "the other way.'

gitude, and making the point of Laguna Blanca, will, from Captain Bouverie's description, take it for Cape St Mary's, and conclude themselves 47 miles from the Island of Lobos, when they are in reality only 17 miles from that island; and if it should be the approach of night, they would thereby subject themselves to the danger of running on Lobos, when they would suppose themselves 30 miles from it. Lobos is a low island of black rocks, and the cries of the numberless swarms of seals would warn a vessel of her approach to it in a fine night, but in blowing weather they could not be heard. The soundings within 5 miles of the point of Laguna Blanca, agree exactly with the soundings described by Captain Bouverie, abreast of St. Mary's."

The Nereus tacked in 12 fathoms water, the prickly pear-hedge, on with Cape St. Mary, bearing north by compass, and the breakers stretching to the S. E. of the Cape N. 7° E.; and her distance from the cape was about 3 miles.