LEADING LIGHTS OF THE BRISTOL CHANNEL.

Trevose Head-on N.W. part-Two fixed lights, visible 19 miles. The lower light is 50 feet in advance of the higher one. Lat. 50° 33' N., long. 5° 1 W. Lundy-on the ridge of the Island-Two

lights in one tower; upper, revolving every 2 minutes; lower, fixed, and visible 30 miles.

Low light only visible from the Westward, between S. by E. to N.E. Flatholm-on the Island, S. Point-One fixed light, and visible 17 miles. English and Welsh Grounds-LightvesselOne revolving light, every minute, and visible 10 miles.

Moored S. side of Bristol Channel, in 6 fathoms. Usk-W. side of entrance of the riverOne fixed light, and visible 10 miles. Red, between the bearings of S.E. E. and S.S.E. E. and between the bearings of S. by E. and S.S. W., from whence into the land it will be White. It will then show White between S.S.E. E. and S. by E. E. to mark

the Channel into the River, and a White strip will show up the river between the bearings of N.E. by E. E. and E. by N. N. Nash-on the Point-Two fixed lights, visible 18 and 16 miles.

The lights in one, N.W. by W. W., lead a cable's length S. of Nash Sand. Mumbles-on the Head-A fixed light, and visible 15 miles.

Searweather-Lightvessel-One Red revolving light, every 20 seconds.

Off the W. end of the Sand. A half globe above usual globe.

Helwick-Light vessel-A light revolving

every minute, and visible 10 miles. Off West end of the Sand, in 16 fathoms. Caldy-on Caldy Island, S. part-A fixed light, and visible 19 miles.

St. Ann's-on St. Ann's Point, Milford
Haven-Two fixed lights, and visible
19 and 17 miles.

When in one, they lead clear of the Crow and
Toes Rocks.

NAVIGATING THE ENGLISH CHANNEL.

WHEN running for the Channel, the ground should invariably be sought for in good time; nor should the lead in any case be neglected after the ground has been once obtained, especially during the night; because in the parallel of 51° 10' N. the same soundings will be found as at 10, 18, 28, and 43 leagues from Scilly. Nor is this identity confined to that latitude alone. By the above precaution, all the various alterations in depth, substance, and colour will be progressively unfolded while advancing to the eastward, and the parallel of latitude with greater facility preserved or regained if temporarily quitted.

Generally speaking, the water in the entrance of the channel is from 8 to 10 fathoms deeper towards the French coast than towards the English. The soundings, too, are coarser; the stones are larger; and the different substances altogether more loose and unconnected, and the compound of a paler colour than on the northern side of the Channel.

THE BEST PARALLEL for entering the Channel is between 49° 15′ and 49° 25', according to the inclination of the wind; because it is between those limits that the relative situation of your vessel can with the greatest certainty be ascertained, as well in respect to depth of water

as to quality of ground (alluding to the discrimination between oaze and sand), and which cannot be so well defined in any other latitude. The keeping on this parallel is rendered still more necessary, in consequence of the rotary motion and northerly inclination of the tide to the westward, south-westward, and southward of Scilly.

Between the parallels of 49° 15′ and 49° 25′ N., the edge of the bank of soundings will be found in the longitude of 11° 18′ W. Here the depths of water will be from 270 to 335 fathoms, and the ground a mixture of sand and dark-greenish oaze. From hence, as you proceed towards the Channel, you will find sand and oaze for 16 leagues further eastward, the depths decreasing very suddenly from 81 and 80 fathoms to 71 and 69, and the ground changing to coarse and fine reddishyellow sand and shingle.

BEST LINE OF APPROACH.-Vessels bound into the Channel from the S.W. run well to the northward, when E. of 10° W. until oaze forms part of the soundings; and when bound from the N.W. run southward, until the soundings are free from oaze, thus infallibly insuring a safe parallel, in the first instance, whereon to run eastward; and as during the prevalence of strong southerly and westerly winds, the tides are warped more astream than usual, and found to run considerably longer, as well as with greater velocity, between the north and west, than at other periods, it is recommended (having in view the preservation of any particular parallel) that, when running from the edge of soundings towards the Channel during spring-tides, and with the wind blowing strong from between south and west, the course should be taken at S.E. by E. instead of, as usual, S.E. by E.

E.

USHANT.-An island 4 miles long and 2 broad, and is nearly in the same longitude as the Lizard; bears from the Lizard lights N. by E. E., 90 miles; therefore, a ship being abreast of either of these places, may be considered to have entered the British Channel. In the parallel of Ushant, and 16 leagues distant you will have 70, 71, or 72 fathoms, the bottom a coarse pale-yellow, having a mealy substance with broken shells, and substance like chaff. At 9 leagues distant, in the same parallel, there are from 63 to 66 fathoms; and even within three leagues, the same depth-therefore, in thick weather, come no nearer to Ushant than 70

fathoms.

The North-West Stream-Or, as it is termed by many, "THE INDRAUGHT of the British Channel," often runs at the rate of 13 miles an hour or more, and in light winds and thick weather, when observations cannot be obtained, the utmost care is requisite in proceeding for the

Channel, in order to satisfy yourself that this current has not thrown you into an unsafe parallel.

ON THE PARALLEL OF FASTNET ROCK, or that of 51° 23′ N., and in 11° 34′ W., are 286 fathoms water-the ground a sort of fine dark viscous brown sand; this is the edge of the bank. Thence, as you proceed eastward, the depth decreases very suddenly. In the longitude of 11°, are 95 fathoms, very fine dark sand; from hence to the longitude of 10° 30', the depth decreases more gradually, viz., about 4 fathoms every 5 miles, but again decreases very suddenly until within 5 leagues of the land. Seven leagues westward of the Mizen Head, there are 60 fathoms, oazy ground, and not further off than 10 leagues, 80 fathoms will be found-the bottom oaze, as before.

ON THE PARALLEL OF TREVOSE HEAD.-Vessels running for the Bristol Channel, and bound into the Severn from the Atlantic, should endeavour to preserve the parallel of Trevose Head, or that of 50° 30′, not only with a view of counteracting the north-westerly and northerly excess of tide which prevails in the Irish Channel, but because the soundings, on approaching it, decreases gradually, and because this promontory projects a considerable distance to the westward beyond the general direction of the Cornish coast. The land, also, being very high and steep, renders it the most eligible spot for a landfall between the Land's End and Hartland Point, from whence a vessel may with confidence shape a course for the Bristol Channel. On this parallel, and in the longitude of 10° 53', are 140 fathoms, fine dark brown sand; this appears to be the edge of the bank of soundings in that latitude. From hence, the transition to shoal water is very sudden, as 13 miles further eastward are only 94 fathoms. This depth is in the longitude of 10° 32′ W., and as you proceed easterly, the depths more gradually decrease. In longitude 9° 44', are 71 fathoms, very fine dark-grey sand, of the consistency of beaten pepper; 7 leagues further eastward, are 71 and 69 fathoms also; the latter soundings are, however, oazy. On the western extreme of the Nymph Bank, are 59, 55, and 53 fathoms, and the south-western extremes of the said bank lie in 60 and 64 fathoms. Proceeding easterly, you will retain nearly the same depths until you advance as far as the longitude of 8° 26', where you will find as little as 53 and even 45 fathoms; coarse, tenacious, light ground. The former depth, 45 fathoms, is the shoalest part of the Nymph, and is in latitude 50° 32′ N., and longitude 8° 26' W.; to the south-westward of this, the soundings vary from 50 to 60 fathoms, and to the eastward of the latter depth, 69 fathoms, they shoalen pretty gradually towards the western coast of Cornwall, 9 leagues from which are 34 fathoms.

THE NYMPH BANK lies nearly midway between the English and Irish coasts, and shoals in irregular, uneven patches. It takes its rise in the vicinity of the Hook Lighthouse, and thence trends along the Irish coast round Cape Clear, even as far westward as the meridian of Dursey Island. It is very steep, particularly on its south-eastern and western edges, and the quality of the ground thereon is principally, though not wholly, that of coarse and fine sand; in some places, however, oaze will come up with the lead. Indeed, the deeper parts are wholly oaze, though not very tenacious.

S.W. OF THE SMALLS.-The soundings, on a radius of 16 leagues from the Smalls Lighthouse, in any direction between N.W. by W. W. and S.W. S., are nearly wholly oaze, or sand mixed therewith. To the north-westward, as well as to the eastward of these limits, the bottom suddenly becomes a sort of dark-reddish sand, which ground is the peculiar criterion of an approach to the Bristol Channel, therefore, if the ground brought up by the lead be oaze, or sand mixed therewith, you cannot be to the southward of 50° 57′ N., but must be to the northward of that parallel, and to the westward of the meridian of Grasholm, let the depth be what it may. If, on the contrary, the soundings are wholly free from oaze, you must be to the eastward of the latter meridian. The transition from oaze to sand in the neighbourhood is so evident that it cannot be mistaken.

THE BISHOP ROCK bears from St. Agnes W. & N., 4 miles.

DANGERS NEAR THE LAND'S END.-The Runnel Stone, Wolf Rock, Longships, and Seven Stones.

THE WOLF ROCK lies E.S.E. E., 21 miles from Scilly Lighthouse, 23 miles W.N.W. from the Lizard Point, and is only 1 miles to the northward of a supposed straight line drawn from the former to the latter. The Longship Light bears from it N.E. N., 7 miles.

The Wolf is very steep on all sides, and is a wash at high water neap tides, though covered on spring floods. A light is being built on this rock.

SEVEN STONES, a cluster of rocks, lying N.N.W. and S.S.E., about a mile in extent, with 38 to 40 fathoms at a mile distant, in all directions. In navigating this channel, the lightvessel should be kept westward of north, when going to the northward; and westward of south, when going in the contrary direction.

RUNNEL STONE.-S.S.E., 4 miles from Longships; when the light is visible you are clear of the Runnel Stone Rock.

THE STAGS.-Off the Lizard; they extend to nearly half a mile from the coast, and have from 5 to 9 fathoms close to and among them.

MANACLES ROCKS.-Some of the rocks are barely covered at high water. They lie S.S.W., 5 miles from Pendinnis Point, S. by E., 3 miles from the entrance to Helford, and E.N.E., 3 miles from the Black Head.

The eastern land of the Lizard (the Beast), open of Black Head W. by S., clears you of the rocks about a mile. At night the Lizard lights kept in sight, clears you 3 miles to the southward.

FALMOUTH.-The lighthouse is on St. Anthony's Point, at the east side of the entrance; some rocks extend a short distance off it.

Old Wall, or Pinnacle Rock, of 26 feet, lies 1 mile from St. Anthony's Point; marks-Milor or Pennarrow Point, midway between St. Anthony's Point and the extremity of the rocks running out from it, bearing N. W. When on it, St. Maw's Castle is hid by St. Anthony's Point.

Having passed the Lizard, bound to Falmouth, keep the Lizard lighthouse open of Black Head until St. Anthony's Light (flashing every 20 seconds) bears N.N.E., which clears the Manacles.* If you are only going to the outer anchorage, steer up, with St. Anthony's bearing N.N.E., until within about 2 miles from it; then keep more to the N.W., and anchor, as convenient, in 8 or 10 fathoms, with the light about N.E. by E.: the harbour will then be open, in case the wind should get round to the eastward.

At the entrance at Falmouth, there is the Black Rock, which dries, with a beacon on it; it lies nearest the west shore; vessels may pass on either side of it, but the cast side is the better passage. In proceeding to Carrick Road, keep in the fairway, and the lead going, as there is a narrow, deep channel all the way of 16 to 18 fathoms. You may borrow on St. Maw's side in 5 or 6 fathoms; or, steer up with Killaganoon House in line with Pennarrow or Milor Point, N. E., which leads in the centre of the channel, between the black buoy on the east side, and the white buoy on the west side of the narrowest part of the channel. When past the buoys, you may anchor in Carrick Roads in 12 to 18 fathoms.

NOTE-Vessels drawing not more than 18 feet, can use the channel westward of the Black Rock at all times of tide. Take the centre of the channel, and steer N.E. by N. THE UDDER ROCK.-It lies 4 miles W. N. from the Loo Island, and is dry at low spring tides.

THE HAND DEEPS lie N.W. N., 34 miles from the Eddystone, with

St. Anthony's fixed light kept in sight between N.N.E. † E. and N. by E. † E. also clears the Manacles.