CHAPTER XXIV._Narrative of the surveying voyages of His Majesty's ships Adventure and Beagle, between the years 1826 and 1836, Vol. 1 [of 3]

A FEW NAUTICAL REMARKS UPON THE PASSAGE ROUND CAPE HORN; AND UPON THAT

THROUGH THE STRAIT OF MAGALHAENS, OR MAGELLAN.

Ships bound from the Atlantic to any of the ports in the Pacific, will find

it advantageous to keep within one hundred miles of the coast of Eastern

Patagonia, as well to avoid the heavy sea that is raised by the westerly

gales, which prevail to the eastward, and increase in strength according to

the distance from the land, as to profit by the variableness of the wind

when it is in the western board. Near the coast, from April to September,

when the sun has north declination, the winds prevail more from the W.N.W.

to N.N.W. than from any other quarter. Easterly gales are of very rare

occurrence, but even when they do blow, the direction being obliquely upon

the coast, I do not consider it at all hazardous to keep the land on board.

In the opposite season, when the sun has south declination, the winds will

incline from the southward of west, and frequently blow hard; but, as the

coast is a weather shore, the sea goes down immediately after the gale. In

this season, although the winds are generally against a ship's making quick

progress, yet as they seldom remain fixed in one point, and frequently

shift backward and forward six or eight points in as many hours, advantage

may be taken of the change so as to keep close in with the coast.

Having once made the land, which should be done to the southward of Cape

Blanco, it will be beneficial to keep it topping on the horizon, until the

entrance of the Strait of Magalhaens be passed.

With respect to this part of the voyage, whether to pass through Strait Le

Maire or round Staten Island, much difference of opinion exists. Prudence,

I think, suggests the {464} latter; yet I should very reluctantly give up

the opportunity that might offer of clearing the strait, and therefore of

being so much more to windward. With a southerly wind it would not be

advisable to attempt the strait; for, with a weather tide, the sea runs

very cross and deep, and might severely injure and endanger the safety of a

small vessel, and to a large one do much damage. In calm weather it would

be still more imprudent (unless the western side of the strait can be

reached, where a ship might anchor), on account of the tides setting over

to the Staten Island side; where, if it becomes advisable to anchor, it

would necessarily be in very deep water, and close to the land. With a

northerly wind the route seems not only practicable, but very advantageous,

and it would require some resolution to give up the opportunity so

invitingly offered. I doubt whether northerly winds, unless they are very

strong, blow through the strait--if not, a ship is drifted over to the

eastern shores, where, from the force of the tides, she must be quite

unmanageable.

Captain Fitz Roy seems to think there is neither difficulty nor risk in

passing the strait. The only danger that does exist, and that may be an

imaginary one, is the failure of the wind. Ships passing through it from

the south, are not so liable to the failure of the south-westerly wind,

unless it be light, and then a breeze will probably be found from N.W., at

the northern end of the strait. The anchorage in Good Success Bay, however,

is at hand, should the wind or tide fail.

In passing to leeward of Staten Island, the tide race, which extends for

some distance off Cape St. John, at the N.E. end of the island, must be

avoided: otherwise there exist no dangers.

The anchorage under New Year Islands, although it is a wild one, the bottom

bad, and the tide very strong, yet offers good shelter from south-west

winds, and might be occupied with advantage during the existence of a gale

from that quarter, which is so unfavourable for ships bound round the Horn.

After passing Staten Island, if the wind be westerly, the {465} ship should

be kept upon the starboard tack, unless it veer to the southward of S.S.W.,

until she reaches the latitude of 60deg south, and then upon that tack on

which most westing may be made. In this parallel, however, the wind is

thought to prevail more from the eastward than from any other quarter.

Never having passed round Cape Horn in the summer season, I may not perhaps

be justified in opposing my opinion to that of others, who, having tried

both seasons, give the preference to the summer months. The advantage of

long days is certainly very great, but, from my experience of the winds and

weather during these opposite seasons at Port Famine, I preferred the

winter passage, and in our subsequent experience of it, found no reason to

alter my opinion. Easterly and northerly winds prevail in the winter off

the cape, whilst southerly and westerly winds are constant during the

summer months; and not only are the winds more favourable in the winter,

but they are moderate in comparison to the fury of the summer gales.

Having passed the meridian of Cape Pillar, it will yet be advisable to take

every opportunity of making westing in preference to northing until the

meridian of 82deg or 84deg be reached, which will enable a ship to steer

through the North-westerly winds that prevail between the parallels of

50deg and 54deg. (See Hall's South America, Appendix.)

With respect to the utility of the barometer as an indicator of the weather

that is experienced off Cape Horn, I do not think it can be considered so

unfailing a guide as it is in the lower or middle latitudes. Captain

Fitz-Roy, however, has a better opinion of the indications shewn by this

valuable instrument: my opinion is, that although the rise or fall at times

precedes the change, yet it more frequently accompanies it. The following

sketch of the movement of the barometer, and of the weather that we

experienced, may be not without its use.

Being to the north of Staten Island for three days preceding full moon,

which occurred on the 3d April (1829), we had very foggy weather, with

light winds from the eastward and {466} northward, causing a fall of the

mercury from 29.90 to 29.56. On the day of full moon the column rose, and

we had a beautiful morning, during which the high mountains of Staten

Island were quite unclouded, as were also those of Tierra del Fuego. At

noon, however, a fresh gale from the S.W. set in, and enveloped the land

with a dense mist. No sooner had the wind changed, than the mercury rose to

29.95, but fell again the next morning; and with the descent the wind

veered round to N.W., and blew strongly with thick cloudy weather and rain,

which continued until the following noon, when the wind veered to S.W., the

barometer at 29.54, having slightly risen; but after the change it fell,

and continued to descend gradually until midnight, when we had a fresh gale

from W.S.W. When this wind set in, the mercury rose, and continued to rise,

as the wind veered without decreasing in strength to S.S.W., until it

reached 29.95, when it fell again and the weather moderated, but without

any change of wind. During the descent of the mercury, the sky with us was

dull and overcast, with squalls of wind and rain, but on shore it seemed to

be very fine sunshiny weather.

The column now fell to 29.23, and during its descent the weather remained

the same, dull and showery; but as soon as the mercury became stationary, a

fresh breeze set in from the southward, with fine weather.

After this to new moon the weather was very unsettled, the wind veering

between South and W.S.W.; the barometer rising as it veered to the former,

and falling as it became more westerly; but on no occasion did it precede

the change.

The mean height of the barometer is about 29.5.

The mercury stands lowest with N.W. winds, and highest with S.E.

With the wind at N.W. or northerly the mercury is low; if it falls to 29

inches or 28.80, a S.W. gale may be expected, but it will not commence

until the column has ceased to descend. It frequently, however, falls

without being followed by this change. In the month of June, at Port

Famine, the barometer fell to 28.17, and afterwards gradually rose to 30.5,

{467} which was followed by cold weather, in which the thermometer stood at

12deg.

The following Table shews the mean temperature and pressure as registered

at the Observatory at Port Famine in the Strait.

+----------+--------------+-----------+

| 1828. | Temperature. | Pressure. |

+----------+--------------+-----------+

| February | 51.1 | 29.40 |

| March | 49.4 | 29.64 |

| April | 41.2 | 29.57 |

| May | 35.5 | 29.30 |

| June | 32.9 | 29.28 |

| July | 33.0 | 29.57 |

| August | 33.2 | 29.28 |

+----------+--------------+-----------+

The difficulties that present themselves to Navigators in passing round

Cape Horn, as well from adverse winds as the severe gales and heavy sea to

which they are exposed, are so great, that the Strait of Magalhaens has

naturally been looked to as a route by which they may be avoided. Hitherto

no chart has existed in which much confidence could be placed; but by the

present survey, the navigation through it, independent of wind and weather,

has been rendered much easier; since a correct delineation of its shores,

and plans of the anchorages, have been made; and in the preceding pages,

sufficient descriptions of them have been given to assure the navigator of

his place, and furnish him with advice as to his proceedings. The local

difficulties therefore have been removed; but there remain much more

serious ones, which I should not recommend a large, or even any but a very

active and fast-sailing square-rigged vessel to encounter, unless detention

be not an object of importance.

For a square-rigged vessel bound through the Strait, the following

directions will be useful:-- {468}

In the eastern entrance the winds will frequently favour a ship's arrival

off the First Narrow; where, if she selects a good anchorage on the bank

which bounds the northern side of the channel, she may await an opportunity

of passing through the First Narrow and of reaching Gregory Bay; where also

a delay may safely be made for the purpose of passing the Second Narrow and

arriving at the neighbourhood of Cape Negro; at which place the

difficulties and dangers of the eastern entrance cease.

The dangers being carefully placed on the chart, and now sufficiently

described, nothing need be repeated here; and indeed much must be left to

the judgment and discretion of the navigator.

The tides answer best for vessels entering the Strait at the period of full

and change of the moon, since there are two westerly tides in the day. In

the winter season, if the morning tide be not sufficient to carry a vessel

through the First Narrow, she may return to Possession Bay, select an

anchorage, and be secured again before night; or, in the summer, if she has

passed the Narrow, and has been enabled to anchor for the tide, there will

be sufficient daylight for her to proceed with the following tide to

Gregory Bay, or at least to a safe anchorage off the peaked hillocks on the

north shore.

I have twice attempted to pass the First Narrow, and been obliged to return

to the anchorage in Possession Bay; and twice I have passed through it

against a strong breeze blowing directly through, by aid of the tide; which

runs, in the narrower parts, at the rate of ten or twelve miles an hour.

When the tide and wind are opposed to each other, the sea is very deep and

heavy, and breaks high over the decks; it is therefore advisable to close

reef, or lower the topsails on the cap, and drift through; for the tide, if

at the springs, will generally be sufficient to carry a ship to an

anchorage, although, not always to one where it would be safe to pass the

night. On this account, it would be prudent to return; for, although the

holding ground is exceedingly good, yet, to part in the night, or drift

towards, or through the Narrow, could scarcely happen without accident.

{469}

In leaving the anchorage in Gregory Bay, attention must be paid to the

tide, which continues to run to the eastward in the Second Narrow, three

hours after it has commenced setting to the S.W. at the anchorage.

With a leading wind through the Second Narrow, a ship will easily reach an

anchorage off Laredo Bay, but, if the tide fails upon emerging from it, she

should seek for a berth in the bay to the north of Elizabeth Island, as

near to the island as possible, but to the westward of its N.E. end, to be

out of the influence of the tide. The depth of water, however, will be the

best guide.

Directions for passing round the south side of Elizabeth Island are given

elsewhere; and as this part offers some dangers, the chart and the

description should be carefully referred to.

The only advice that seems wanting, to improve the directions for the coast

from this to Port Famine, is, with a south-westerly wind, to keep close to

the weather shore, in order to benefit by the flaws down the valleys; but

this must be done with caution, in consequence of the squalls off the high

land, the violence of which cannot be well imagined by a person

unaccustomed to them.

Of the anchorages between Port Famine and Cape Froward, the only convenient

one for a ship is St. Nicholas Bay, to which, if defeated in passing round

the Cape, she had better return; for it is easy to reach as well as to

leave, and extremely convenient for stopping at, to await an opportunity of

proceeding.

From Cape Froward to the westward, unless favoured by a fair wind, it is

necessary to persevere and take advantage of every opportunity of advancing

step by step. There are several anchorages that a ship may take up, such as

Snug Bay, off Woods Bay, near Cape Coventry, in Fortescue Bay, Elizabeth

Bay, and York Roads. To the westward, in Crooked Reach, the anchorages are

not so good, and excepting Borja Bay, none seem to offer much convenience.

Borja Bay, however, is well calculated to supply the deficiency, although

for a square-rigged vessel there must be some difficulty in reaching it.

{470}

Long Reach is both long and narrow, and ill supplied with anchorages for a

ship; such as they are, Swallow Harbour, Playa Parda, Marian Cove, and Half

Port Bay, seem to be the best. In thick weather, although the channel is

very narrow, yet one side is scarcely visible from the other, and the only

advantage it has over other parts of the strait is the smoothness of the

water. In Sea Reach there is a heavy rolling swell, with a short and deep

sea, which renders it very difficult to beat to windward.

Tamar Harbour, Valentine Harbour, Tuesday Cove, and the Harbour of Mercy,

are the best anchorages; and the latter is particularly convenient to

occupy, while awaiting an opportunity of sailing out of the strait.

In the entrance, the sea runs very heavy and irregularly during and after a

gale; so that a ship should not leave her anchorage in the Harbour of

Mercy, without a fair or a leading wind to get her quickly through it.

For small vessels, particularly if they be fore-and-aft rigged, many, if

not all of the local difficulties vanish; and inlets which a ship dare not

or cannot approach, may be entered with safety, and anchorage easily

obtained by them. A large ship will perhaps be better off in entering and

leaving the Strait where there is open space and frequently a heavy sea;

but for the navigation of the Strait, a small vessel has considerably the

advantage. She has also the opportunity of passing through the Cockburn

Channel should the wind be north-westerly, which will very much reduce the

length of the passage into the Pacific.

One very great advantage to be derived from the passage through the Strait

is, the opportunity of obtaining as much wood and water as can be required,

without the least difficulty; and another benefit is, that by hauling the

seine during the summer months, from January to May, at the mouth of the

river or along the beaches in Port Famine, at the first quarter flood, a

plentiful supply of fish may be obtained. Excellent fish are also caught at

the anchorage with the hook and line, at all seasons, early in the morning

or late in the {471} evening. Fish may also be obtained with the seine at

any other place where there are rivers. Freshwater Bay and Port Gallant are

equally productive. On the outer coast of Tierra del Fuego an excellent

fish may be caught in the kelp.

The advantage which a ship will derive from passing through the Strait,

from the Pacific to the Atlantic is very great; and it ought to be great to

induce the seaman to entangle his ship with the land when fair winds and an

open sea are before him. After passing through the Strait, the prevailing

winds being westerly, and more frequently from the northward than from the

southward of west, they are fair for his running up the coast; or if not,

the ship is not liable to receive much injury from the sea, which is

comparatively smooth; whereas, to a ship passing round the Horn, if the

wind be north-west she must go to the eastward of the Falkland Islands, and

be exposed to strong gales and a heavy beam sea, and hug the wind to make

her northing. To a small vessel the advantage is incalculable; for, besides

filling her hold with wood and water, she is enabled to escape the severe

weather that so constantly reigns in the higher latitudes of the South

Atlantic Ocean.

Coming from the northward, it will be advisable to keep an offing until the

western entrance of the Strait is well under the lee, to avoid being thrown

upon the coast to the northward of Cape Victory, which is rugged and

inhospitable, and, forming as it were a breakwater to the deep rolling

swell of the ocean, is for some miles off fringed by a cross hollow sea

almost amounting to breakers.

The land of Cape Victory is high and rugged, and much broken; and if the

weather be not very thick, will be seen long before the Evangelists, which

are not visible above the horizon, from a ship's deck, for more than four

or five leagues.[206] Pass to the southward of them, and steer for Cape

Pillar, {472} which makes like a high island. In calm weather do not pass

too near to the cape, for the current sometimes sets out, and round the

cape to the southward; but with a strong wind, get under the lee of it as

soon as you please, and steer along the shore. In the night it will be

advisable to keep close to the land of the south shore; and if a patent log

be used, which no ship should be without, your distance will be correctly

known. The course along-shore, by compass, is E. 3/4 S.; and if the weather

be hazy, by keeping sight of the south shore, there will be no difficulty

in proceeding with safety.

The Adventure entered the Strait on the 1st of April, 1830, at sunset; and

after passing within half a mile of the islets off the Harbour of Mercy,

steered E. 3/4 S. magnetic, under close-reefed topsails, braced by, the

weather being so squally and thick that the land was frequently concealed

from us; but being occasionally seen, the water being quite smooth, and the

course steadily steered, with the patent log to mark the distance run, we

proceeded without the least anxiety, although the night was dark, and the

squalls of wind and rain frequent and violent. When abreast of Cape Tamar,

that projection was clearly distinguished, as was also the land of Cape

Providence, which served to check the distance shewn by the patent log; but

both giving the same results, proved that we had not been subjected to any

current; whereas the account by the ship's log was very much in error, in

consequence of the violence of the squalls and the long intervals of light

winds, which rendered it impossible to keep a correct account of the

distance. At daybreak we were between Cape Monday and the Gulf of

Xaultegua; and at eight o'clock we were abreast of Playa Parda, in which,

after a calm day, the ship was anchored.

In the summer season there is no occasion to anchor any where, unless the

weather be very tempestuous, for the nights are short, and hardly dark

enough to require it, unless as a precautionary measure, or for the purpose

of procuring wood and water; the best place for which is Port Famine, where

{473} the beaches are strewed with abundance of logs of well-seasoned wood,

which is very superior to the green wood that must otherwise be used.

Notwithstanding that the Adventure experienced no current in the western

part of the Strait, there is generally a set to the eastward, which is more

or less felt according to circumstances. The direction and strength of the

currents are caused by the duration of the gales.

The chart will be a sufficient guide for vessels bound through from the

westward as far as Laredo Bay; after which a few directions will be

necessary. The land here should be kept close on board, to avoid the Reef

off the south-west end of Santa Magdalena. Being abreast of it, bear away,

keeping the N.E. extremity of Elizabeth Island on the starboard bow, until

you see Santa Marta in one with, or a little to the southward of, the south

trend of the Second Narrow (Cape St. Vincent), which is a leading mark for

the fair channel until you pass the spit of shoal soundings, which extends

across to Santa Magdalena. There are also shoal soundings towards the

south-west end of Elizabeth Island; at half a mile off we had five

fathoms,--Cape St. Vincent being then the breadth of Santa Marta open to

the northward of that island. Keeping the cape just in sight to the

northward of Santa Marta, steer on and pass round the low N.E. extremity of

Elizabeth Island, off which are several tide eddies. The tide here sets

across the channel.

Now steer for the Second Narrow, keeping Cape Gregory, which will be just

discernible as the low projecting extreme of the north side of the Second

Narrow, on the starboard bow, until you are three miles past Santa Marta;

the course may then be directed for the cape, opening it gradually on the

larboard bow as you approach it, to avoid the shoal that extends off it.

If you anchor in Gregory Bay, which is advisable, in order to have the

whole of the tide for running through the First Narrow, haul up and keep at

a mile and a half from the shore. When {474} the north extremity of the

sandy land of the Cape is in a line with the west extreme of the high

table-land, you will be near the anchorage; then shorten sail, and when the

green slope begins to open, you will have fourteen fathoms: you may then

anchor or keep away to the N.E., and choose a convenient depth, taking care

not to approach the shore, so as to bring Cape Gregory to the southward of

S. by W. 1/4 W. (by compass). The best berth is with the Cape bearing

S.S.W.

Hence to the First Narrow, the course by compass is due N.E. by E.[207] The

land at the entrance being low, will not at first be perceived; but,

steering on, you will first see some hummocky land, making like islands.

These are hills on the eastern, or Fuegian side of the Narrow. Soon

afterwards, a flat, low sand-hill will be seen to the northward, and this

is at the S.W. extremity of Point Barranca. On approaching the narrow, at

four miles off, keep a cliffy head, four or five miles within the east side

of the narrow, open of the trend of Point Barranca, by which you will avoid

the shoal that extends off the latter point. You should not go into less

depth than six fathoms. At most times of the tide there are long lines and

patches of strong ripplings, through which you must pass. The shoal is

easily distinguished by the kelp.

When the channel through the narrow bears by compass N. by E. 3/4 E., steer

through it; and that, or a N.N.E. course, will carry you through. On each

side, the bank extends off for some distance; but by keeping in

mid-channel, there is no danger until the cliffy coast be past, when reefs

extend off either shore for some distance, particularly off Cape Orange.

The N.N.E. course must be kept until the peak of Cape Orange bears south,

and the northern Direction Hill W.S.W., or W. by S. 1/2 S. by compass. Then

steer E.N.E. for Cape Possession, taking care not to approach too near to

the bank {475} off Cape Orange, or to that on the north side of Possession

Bay, for which the chart must be consulted.

For a small vessel, the passage through the strait, from west to east, is

not only easy, but strongly to be recommended as the best and safest route.

Indeed, I think the passage would be quite as expeditious, and perhaps much

safer, to enter the Gulf of Trinidad, and pass down the Concepcion Strait,

the Sarmiento or St. Estevan Channels, and Smyth Channel, and enter the

Strait at Cape Tamar. In these channels northerly winds prevail, and there

is no want of convenient and well-sheltered anchorages for the night, many

of which have already been mentioned, and multitudes of others, perhaps

much better ones, might be found.

* * * * *

APPENDIX.

------

TABLES of LATITUDE and LONGITUDE, VARIATION of the COMPASS, TIDE, and

HEIGHT.

MAGNETIC OBSERVATIONS, discussed by MAJOR SABINE, R.A., F.R.S.

ZOOLOGY; including MAMMALIA--BIRDS--and SHELLS.

COPIES of ORDERS.

EXTRACTS from a PAPER published in the JOURNAL of the ROYAL GEOGRAPHICAL

SOCIETY.

EXTRACT from a GAME-BOOK.

INDEX.

* * * * *

{479}

TABLES

LATITUDE AND LONGITUDE, VARIATION OF THE COMPASS, AND TIDE.

------

COASTS OF BRAZIL, RIVER PLATA, AND EASTERN PATAGONIA.

------

The Latitudes to which the character * is prefixed, have resulted from

Astronomical Observation. The Longitudes which have been determined by

Chronometers, are designated by C.; and those by Lunar Distances by *).

Those without distinguishing marks are the result of Triangulation.

The Longitudes in the following Tables depend upon that of Villegagnon

Island at Rio de Janeiro, which was found by fourteen Chronometers from

Plymouth to be 43deg 05' 03" West of Greenwich.

---------------------------+---------+----------+------+-----------------

Name of | | | | TIDE

---------------------------+ | | |-----+-----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+-----------

Coast of Brazil. | deg ' "| deg ' "| deg '|H. M.|

================ | | | | |

Arsenal |*23 55 51|C.46 16 33| 4 22| |

Moela Lighthouse |*24 03 06|C.46 12 20| | |

Centre |*24 08 10|C.45 39 15| | |

Centre |*25 07 28|C.47 52 51| | |

Centre |*25 21 29|C.47 54 11| | |

Fort on the Bar |*25 30 14|C.48 17 10| 5 44| |

West Point of Cotinga |*25 29 50|C.48 26 32| 5 34| |

Church of Sta Antonina |*25 25 42|C.48 39 52| | |

Sta Cruz d'Anhatomirim |*27 25 35|C.48 29 41| 6 30| |

City, President's House |*27 35 30| | | |

Extremity | 34 40 20|C.54 05 58| | |

---------------------------+---------+----------+------+-----+-----------

============ | | | | |

Well at N.E. end |*34 57 00|C.54 53 38| 13 48| |

| |*)54 53 40| | |

Rat Island, Flagstaff |*34 53 23| 56 09 30| 11 23| |

Cathedral, Cupola |*34 54 37| 56 07 35| 12 07| |

Lighthouse on Mount |*34 53 21| 56 11 04| | |

Cathedral | 34 35 50|C.58 17 53| | |

---------------------------+---------+----------+------+-----+-----------

======================== | | | | |

Observy marked on Plan |*44 30 45|C.65 17 25| 19 10| 4 0|17 feet

Hill at projecting Point | 44 58 00| | | |

North Point | 47 15 00| | | |

Ruins |*47 45 05|C.65 51 45| 19 42|12 10|18-1/2 feet

{480}

Mount at North end | 47 54 45| 65 41 30| | |

Sandy Beach at S. side |*47 56 49|C.65 44 00| 20 47|12 45|20 feet

Rock | 48 08 25| 65 52 56| | |

Monte Video | 48 18 55| 66 18 00| | |

Rock | 48 30 50|C.66 09 25| | |

Shag Island, in Harbour |*49 16 00|C.67 38 02| 22 17|10 30|rises 38

Wood Mount | 49 14 00| 67 43 34| | |

Cape Curioso | 49 11 10| 67 34 30| | |

Extremity | 49 41 18| 67 34 30| | |

Observatory opposite | | 68 25 00| 20 54|10 15|33 feet

Sea-Lion Island |*50 06 43|C.68 22 42| | |

Mount Entrance |*50 08 30| 68 19 10| | |

Station up the River |*49 57 30| 68 52 55| | |

---- |*50 07 30| 69 08 00| | |

Brink | 50 14 30| 68 31 15| |12 15|Northw.

Summit | 50 20 00| 68 49 30| | |

Summit |*50 32 35| 69 00 40| | |

Height on South side |*50 58 27| 69 06 50| | 9 30|

of Entrance | |C.69 05 17| | |

Station up the Inlet | 51 06 30| 69 24 10| | |

Extremity | 51 06 56| 69 03 30| | |

Summit | 51 21 36| 69 01 50| | |

| |C.69 03 28| | |

South extreme. | 51 32 05| 68 55 15| | 9 0|N.W.28 feet

Observatory Mound |*51 33 21| 68 57 50| 21 47| 8 50|46 feet

| |C.68 56 42| | |

---- | 51 49 56| 69 24 30| | |

Smallest & Northernm. | 51 49 12| 69 10 00| | |

Largest & Southernm. | 51 50 08| 69 09 00| | |

Northern | 51 52 09| 69 18 40| | |

Southern | 51 53 01| 69 17 00| | |

---------------------------+---------+----------+------+-----+

* * * * *

{481}

TABLE II.

------

STRAIT OF MAGALHAENS,

INCLUDING

THE COCKBURN AND BARBARA CHANNELS, AND THE OTWAY AND SKYRING WATERS.

Column 1 titles:

A - Coast, &c.

B - East Entrance

C - Possession Bay

D - Eastern part (2d Narrow to Port Famine)

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

East Entrance | deg ' "| deg ' "| deg '|H. M.|

============= | | | | |

S.E. extreme. |*52 18 35| 68 16 55| 22 30| |Northward.

| |C.68 17 46| | |

Extremity | 52 22 40| 68 21 50| | |

Summit | 52 18 25| 68 30 00| | |

---------------------------+---------+----------+------+-----+-----------

============== | | | | |

Centre of Cliff | 52 16 35| 68 53 35| | |

Summit | 52 06 35| 69 30 30| | |

Cape Orange | | | |H. W. about 3 0,

Peak on the S. side of | 52 28 10| 69 26 05| |but the tide

the entrance of the | | | |begins to set to

first Narrow | | | |the N.E. at noon.

Summit 5 miles inland | 52 42 30| 68 40 51| | |

---------------------------+---------+----------+------+-----+-----------

Eastern part (2d Narrow to Port Famine) | | |

======================================= | | |

Extremity | 52 38 18| 70 09 50| | |

Bush on summit of land |*52 38 03|C.70 09 51| 23 34| |

North-east bluff. |*52 49 18|C.70 33 25| | |

Entrance | 52 42 20| 70 31 06| | |

Beach opposite the | 52 46 45| 70 40 31| 23 49| 12 0|

South-east extreme | 52 56 44|C.70 45 30| | |

Extremity | 53 09 00| 70 49 31| | |

---- |*53 21 40| 70 54 01| 23 26| |

| |C.70 53 26| | |

---- | 53 35 18| 70 51 58| | |

Observatory |*53 38 12|C.70 54 01| 23 30|12 0|South.

| |*) | | |5 or 6 ft.

Point Santa Anna | 53 37 55| 70 51 19| | |

Extremity | 53 23 30| 70 24 01| | |

---- | 53 28 35| 70 12 01| | |

Summit at extreme | 53 33 30| 70 30 01| | |

Summit | 53 32 30| 70 01 36| | |

---------------------------+---------+----------+------+-----+-----------

{482}

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

Admiralty Sound | deg ' "| deg ' "| deg '|H. M.|

=============== | | | | |

Rivulet in the Bay | 54 17 10| 69 58 01| | |

Extremity | 54 16 45| 69 50 51| | |

Summit of Mount Hope | 54 26 30| 68 59 11| | |

Summit | 54 19 35| 70 08 31| | |

---------------------------+---------+----------+------+-----+-----------

===========================| | | | |

Summit | 54 19 05| 69 46 36| | |

Project point on W. side | 54 23 00| 69 34 01| | |

Outer point on W. side | 54 25 20| 69 16 31| | |

Point | 54 21 00| 69 12 01| | |

Islet in Ph. Gidley Cove |*53 48 15| 70 31 46| | |

Extremity |*54 03 47| 70 25 31| | |

Rivulet |*54 16 28| 70 13 46| | |

Summit | 54 06 50| 70 23 01| | |

South Extremity, or | 54 19 00| 70 15 21| | |

---------------------------+---------+----------+------+-----+-----------

=============== | | | | |

Port | 54 20 20| 69 19 01| | |

Midway | 54 15 08| 69 32 31| | |

Summit | 54 06 35| 70 48 01| | |

---------------------------+---------+----------+------+-----+-----------

============= | | | | |

South summit | 53 45 00| 70 33 46| | |

Centre | 53 42 10| 70 42 01| | |

Humming Bird Cove |*53 53 52| 70 50 26| | |

| 53 54 25| | | |

S.W. pt of North Island | 53 54 03| 70 51 51| | |

---------------------------+---------+----------+------+-----+-----------

Coast from Pt. Famine to C. Froward | | | |

=================================== | | | |

Peak at North end | 53 45 06| 70 58 26| | |

Extremity | 53 47 00| 70 55 03| 23 30| 1 0|8 feet

Extremity | 53 49 25| 71 00 31| | |

South-east point | 53 50 23| 71 00 56| | |

Islet in the centre | 53 50 38| 71 03 13| | 2 6|

---------------------------+---------+----------+------+-----+-----------

{483}

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

Cape Froward to the Jerome | deg ' "| deg ' "| deg '|H. M.|

================== | | | | |

Summit of the Morro | 53 53 43| 71 14 31| | 1 0|N.E.

S. point of Wood Bay | 53 48 33| 71 35 41| | |

Summit of Peak | 53 57 32| 71 24 13| | |

Small rock in Harbour |*53 57 48| 71 27 46| 24 18| |

Outer-point West side | 53 42 55| 71 53 08| | |

N.W. pt. Bradley Cove |*53 53 15| 71 47 16| | |

Islet off it | 53 50 20| 71 51 41| | |

Extremity |*53 42 11| 71 59 01| 24 35| |

Wigwam Point |*53 41 43|C.71 56 57| 24 04| 9 3|5 or 6 ft.

Wallis Mark | 53 43 57| 72 02 00| | |

Summit | 53 42 00| 72 08 00| | |

Summit of largest island | 53 39 40| 72 08 39| | |

Passage Point Reef | 53 37 00| 72 08 41| | |

Extremity |*53 32 35| | | |

Entrance | 53 33 00|C.72 17 11| 24 06| 1 46|

| | 72 15 41| | |

Bluff extremity, or | 53 31 00| 72 20 41| | |

---------------------------+---------+----------+------+-----+-----------

============= | | | | |

Extremity | 53 33 03| 72 22 16| |At Borja Bay.

| | | | 1 50|6 feet

Extremity | 53 33 20| 72 28 31| | |

Extremity | 53 32 10| 72 29 41| | |

---------------------------+---------+----------+------+-----+-----------

========== | | | | |

Centre of Ulloa Island | 53 31 30| 72 36 13| | |

Extremity | 53 25 00| 72 45 11| | |

Anchorage | 53 18 30| 72 56 00| | 1 8|

Centre |*53 11 36|C.73 14 57| | |

Extremity | 53 09 12| 73 18 16| | |

---------------------------+---------+----------+------+-----+-----------

========= | | | | |

Centre | 53 06 30| 73 12 46| | |

Extremity, North trend | 53 04 03| 73 32 16| | |

---------------------------+---------+----------+------+-----+-----------

{484}

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

Sea Reach | deg ' "| deg ' "| deg '|H. M.|

========= | | | | |

---- | 52 59 00| 73 31 00| 23 22| |

Observatory, Tamar Bay |*52 55 06|C.73 44 02| 23 24| 3 5|5 feet

Extremity of Cape | 52 55 30| 73 44 26| | |Eastwd.

Stragglers, Southernmost | 52 48 03| 73 46 00| | |

Sholl Bay |*52 44 05|C.73 48 20| | |

Summit over the Cape | 52 44 20| 73 53 00| | |

Station near it |*52 41 49|C.74 07 10| | |

Station on its East side |*52 56 31| | | |

Extremity | 52 56 00| 74 09 00| | |

Mount (see Plan) | 52 55 00| 74 15 00| | 2 0|

Extremity |*52 53 19| 74 17 30| | |

Extremity | 52 49 37| 74 22 56| 23 40| |

Eastern summit | 52 37 18| 74 20 26| | |

---- |*52 28 58|C.74 32 18| 25 09| 3 0|

Observation Islet |*52 44 57|C.74 35 31| 23 48| 1 47|4 feet

| | | | or |

| | | | 0 58|

Extremity | 52 42 53|C.74 37 41| | 1 0|

| | 74 39 31| | |

Extremity |*52 16 10|C.74 50 55| | |

Sugar Loaf to South | 52 24 18| 75 02 56| | |Variable

---------------------------+---------+----------+------+-----+-----------

================ | | | | |

Pinnacle on summit | 54 06 28| 70 57 40| | |

Extremity | 54 06 50| 70 53 26| | |

Centre pinnacle | 54 10 40| 70 56 00| | |

Summit of Jane Island | 54 19 10| 70 57 36| | |

Extremity | 54 24 08| 71 04 00| | |

---- | 54 24 08|C.71 05 25| 24 57| |

N.E. peak (6800 feet) | 54 27 00| 70 47 30| | |

---------------------------+---------+----------+------+-----+-----------

{485}

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

Cockburn Channel | deg ' "| deg ' "| deg '|H. M.|

================ | | | | |

Summit | 54 22 38| 71 13 15| | |Westw^d

Station | 54 22 13| 71 20 57| | |

Beach on isthmus | 54 19 00| 71 15 00| 24 56| 0 30|6 or 7 ft.

Cove at the N. end of | 54 18 15| 71 35 50| | |

Centre | 54 17 45| 71 37 00| | |

Body | 54 22 30| 71 42 30| | |

Centre | 54 13 00| 71 53 31| | |

---------------------------+---------+----------+------+-----+-----------

============== | | | | |

Summit (3000 feet) | 54 24 44| 72 07 40| | |

Cove near it |*54 24 23|C.72 02 07| 25 19| |

| | 72 02 31| | |

Entrance |*54 24 27|C.72 14 51| | |

| | 72 14 30| | |

West Point | 54 28 25| 72 15 00| | |

Body | 54 34 30| 72 17 00| | |

Body | 54 38 00| 72 08 00| | |

Summit over extremity | 54 38 48| 72 02 46| | |

Peaks over | 54 23 30| 72 26 46| | |

Summit | 54 23 50| 72 21 41| | |

---------------------------+---------+----------+------+-----+-----------

=============== | | | | |

Centre | 54 19 30| 72 09 00| | |

Summit | 54 18 12| 72 16 00| | |

South point | 54 15 30| 72 16 51| 24 0| 0 30|6 or 7 ft.

Anchorage | 54 12 20| 72 16 00| | |

Summit | 54 09 54| 72 11 51| | |

---- | 54 09 25|C.72 11 21| 24 12| |

Entrance | 54 00 15| 72 18 31| 24 0| 0 30|7 or 8 ft.

Point Cairncross | 53 51 06| 72 16 31| | |

Summit | 53 53 04| 72 06 00| | |

North end | 53 51 24| 72 10 31| | 0 0|[208]

---------------------------+---------+----------+------+-----+-----------

{486}

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

Barbara Channel | deg ' "| deg ' "| deg '|H. M.|

=============== | | | | |

Latitude Beach |*53 48 40| 72 09 36| | |

Extremity | 53 49 12| 72 00 11| | |

Extremity | 53 47 03| 72 05 16| | |

---------------------------+---------+----------+------+-----+-----------

============== | | | | |

Northernmost | 53 29 30| 72 15 46| | |

Centre | 53 28 30| 72 20 20| | |

Centre | 53 24 30| 72 23 55| | |

---------------------------+---------+----------+------+-----+-----------

============ | | | | |

Centre | 53 21 45| 72 23 20| | 4 0|

Smallest islet |*53 21 49|C.72 28 55| | |

| | 72 26 00| | |

---------------------------+---------+----------+------+-----+-----------

=========== | | | | |

---- |*53 13 14| 72 16 46| | |

Gidley islet at S. | 53 11 00| 72 08 30| | 5 0|

---- |*53 07 00|C.72 00 51| 23 58| 5 0|

| | 71 58 00| | |

North Point |*53 04 20|C.71 52 27| 23 56| 4 0|

| | 71 49 30| | |

Extremity |*52 51 34| 71 29 50| | |

Extremity | 52 49 45| 71 22 10| | 4 0|N.W.

---------------------------+---------+----------+------+-----+-----------

================ | | | | |

Spot marked on Plan |*52 45 30|C.71 21 36| 23 40| |

| | 71 19 55| | |

Do. |*52 39 30|C.71 25 20| 23 34|Sets to East

| | 71 24 10| |until 1 30

---------------------------+---------+----------+------+-----+-----------

============= | | | | |

Centre | 52 52 40| 72 18 00| | |

Summit | 52 34 30| 72 28 40| | |

---------------------------+---------+----------+------+-----+-----------

* * * * *

{487}

TABLE III.

------

THE WESTERN COAST, AND INTERIOR SOUNDS,

FROM

THE STRAIT OF MAGALHAENS TO THE NORTH EXTREMITY OF THE GULF OF PENAS.

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

Smyth Channel | deg ' "| deg ' "| deg '|H. M.|

============= | | | | |

---- |*52 43 25| 73 44 25| | |

South point of entrance |*52 41 10| 73 44 40| 23 04| |

North point |*52 34 16| 73 42 45| 23 20| 0 30|6 or 7ft.

Larch Island |*52 25 38| 73 43 25| | |

Anchorage | 52 23 50| 73 40 15| | |

Summit of larger island | 52 20 25| 73 39 20| | |

Rivulet | 52 15 48| 73 41 25| 23 40| 0 50|7 or 8 ft.

Extremity | 52 13 38| 73 38 40| | |

Centre | 52 10 30| 73 36 40| | |

Entrance of Cove | 52 09 15| 73 43 03| 23 40| 0 50|7 or 8 ft.

Extremity | 52 00 50| 73 45 40| | |

Island at south side | 51 59 05| 73 49 00| | |

Anchorage | 51 54 08| 73 53 15| | |

N.W. point |*51 50 04| 74 05 20| | |

Summit | 51 41 35| 74 15 00| | |

---------------------------+---------+----------+------+-----+-----------

================== | | | | |

---- |*51 47 22| 74 09 30| 24 09| |

Summit | 51 48 10| 74 21 00| | |

Extremity | 51 31 45| 74 04 57| | |

Extremity | 51 27 15| 74 06 20| | |

Rock on West side |*51 26 27| 74 07 00| 24 40| |

---------------------------+---------+----------+------+-----+-----------

=================== | | | | |

Anchorage | 51 22 00| 74 12 00| | |Northw.

Summit | 51 15 04| 74 12 00| | |

Extremity | 51 06 10| 74 16 40| | |

---------------------------+---------+----------+------+-----+-----------

{488}

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

St. Estevan Channel | deg ' "| deg ' "| deg '|H. M.|

=================== | | | | |

North point of entrance | 51 02 12| 74 16 00| | |

North point of entrance | 50 55 00| 74 16 40| | |

---- |*50 50 54| 74 16 00| | |

North extremity in | 50 43 00| 74 23 10| | 2 8|Southw.

---------------------------+---------+----------+------+-----+-----------

================= | | | | |

Centre | 50 55 00| 74 09 40| | |

N. pt. of Schooner Cove |*50 58 35| 74 07 10| 21 00| 1 40|Flood sets

Entrance. | 51 13 40| 73 59 00| | |

---- | 51 23 50| 74 00 35| | |

Northern trend | 51 30 00| 73 58 35| | |

Extremity | 51 38 05| 73 56 55| | |

---- | 51 46 05| 73 51 15| | |

Isthmus | 51 40 35| 73 37 00| | |

Rock off the Extremity | 51 46 35| 73 48 00| | |

---------------------------+---------+----------+------+-----+-----------

=========== | | | | |

Anchorage | 51 51 30| 73 42 30| | |

Extremity | 51 55 00| 73 42 30| | |

Summit | 51 58 45| 73 39 10| | |

---- | 52 06 05| 73 36 55| | |

---- | 52 04 10| 73 27 20| | |

West point |*52 06 03| 73 23 58| | |

North Extremity | 52 07 30| 73 27 40| | |

---------------------------+---------+----------+------+-----+-----------

=============== | | | | |

Centre peak | 52 19 42| 73 22 00| | |

Earnest | 52 12 20| 73 15 15| | |

Extremity | 52 10 52| 73 14 30| | |

Islets within anchorage | 52 11 00| 73 10 30| | |

Beach |*52 05 32| 73 08 35| | |

Extremity | 52 04 38| 73 02 20| | |

" " |*52 03 39| 72 58 50| | |

---------------------------+---------+----------+------+-----+-----------

{489}

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

Interior Sounds | deg ' "| deg ' "| deg '|H. M.|

=============== | | | | |

S. E. Point |*52 06 16| 72 58 00| | |

Beach |*51 53 10|C.72 53 16| | |

Bottom | 51 34 00| 73 23 00| | |

---- | 51 25 38| 73 09 48| | |

Summit (centre) | 51 53 23| 72 44 15| | |

Bottom | 52 29 00| 72 53 35| | |

Skyring Water | 52 22 35| 72 29 40| | |

S. W. Extremity | 50 39 52| 74 29 38| | |

---------------------------+---------+----------+------+-----+-----------

================= | | | | |

Anchorage | 50 34 10|C.74 32 57| | |

Summit at North End | 50 31 55| 74 43 00| | |

Extremity | 50 28 55| 74 38 30| | |

---- | 50 24 30| 74 48 35| | |

Beach | 50 21 15| 74 48 00| | |

Michael |*50 16 48| 74 44 45| | |

anchorage | 50 14 42| 74 36 48| | |

Anchorage | 50 25 08| 74 13 15| | |

Beach near anchorage | 50 11 00| 74 41 30| | |

Summit of Island off | 50 07 00| 74 31 00| | |

Extremity | 50 08 35| 74 37 25| | |

---------------------------+---------+----------+------+-----+-----------

================ | | | | |

Summit |*50 05 30| 74 44 15| | |

Beach | 50 03 12| 74 38 00| | |

Eastern Peak | 49 57 35| 74 36 00| | |

Summit | 49 46 03| 74 40 50| | |

Beach |*49 53 54|C.74 55 57| | |

Summit | 50 00 15| 75 09 35| | |

Observatory |*50 00 18|C.75 15 11| 20 50|Noon.|5 feet

---------------------------+---------+----------+------+-----+-----------

{490}

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

Gulf of Trinidad | deg ' "| deg ' "| deg '|H. M.|

================ | | | | |

Body | 49 54 48| 75 14 02| | |

extremity | 50 02 00| 75 19 30| | |

Extremity | 49 50 04| 75 32 07| 20 58| |

---------------------------+---------+----------+------+-----+-----------

============ | | | | |

Summit | 49 45 02| 75 28 55| | |

---- | 50 01 20| 74 27 00| | |

East Point. | 50 45 25| 74 13 10| | |

Bold Head | 49 32 18| 74 03 20| | |

Head |*49 31 46| 74 00 00| | 1 15|W.S.W.

---------------------------+---------+----------+------+-----+-----------

================= | | | | |

Cape Wellesley, extrem. | 49 28 15| 73 51 30| | |

---- | 48 56 50| 73 40 00| | |

---------------------------+---------+----------+------+-----+-----------

============== | | | | |

West point. | 49 25 35| 74 10 40| | |

Outer point, N. side | 49 07 35| 74 11 30| | |

South end | 49 06 00| 74 13 20| 12 45| |

North end | 48 55 30| 74 13 38| | |

---- |*48 53 50| 74 13 10| |12 30|S.S.E.

side of entrance |*48 39 23| 74 11 20| | |

Bottom | 48 47 00| 74 10 10| | |

Rock off the entrance |*48 30 46| 74 15 35| | |

North point | 48 27 35| 74 20 50| |12 0|Northw.

Bottom | 48 17 00| 74 22 00| | |N. by W.

West point | 48 06 25| 74 28 38| | |

South extreme | 48 03 20| 74 35 30| | |

North extreme | 47 55 12| 74 41 50| | |

Summit at South end | 47 45 10| 74 37 30| | |

Extremity | 47 44 37| 74 52 45| | |

---------------------------+---------+----------+------+-----+-----------

================= | | | | |

Summit on the largest | 47 34 22| 74 40 30| | |

Easternmost point | 47 41 05| 74 55 25| | |

the Wager's wreck | 47 39 40| 75 06 30| | |

---------------------------+---------+----------+------+-----+-----------

{491}

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

Guaianeco Islands | deg ' "| deg ' "| deg '|H. M.|

================= | | | | |

North Beach |*47 40 17|C.75 08 34| | |

| | 75 10 20| | |

South end | 47 45 30| 75 05 45| | |

Summit | 47 38 30| 75 14 25| | |

Isthmus at the bottom | 47 45 00| 75 20 50| | |

Most western point | 47 44 50| 75 24 32| | |

---------------------------+---------+----------+------+-----+-----------

============= | | | | |

South entrance | 47 30 20| 74 33 20| | |

and westernmost | 47 29 30| 74 24 50| | |

E side of northern islet |*47 28 56|C.74 24 13| | |

Bottom of east arm | 47 35 12| 73 53 32| | |

Bottom of south arm | 47 46 10| 74 09 20| | |

Ignacio Bay (beach) |*47 10 28|C.74 25 49| 19 50| |

Xavier Bay (Lyndsey Pt) | 47 05 00| 74 16 40| | |

Harbour | 47 07 15| 74 12 30| | |

North point of entrance |*46 58 54|C.74 05 41| | |

North-east point | 46 51 15| 74 21 50| | |

of entrance | 46 47 40| 74 15 50| | |Quintin

Summit | 46 55 30| 74 39 55| | |

Centre | 46 50 20| 74 41 35| | |

Observatory |*46 49 31|C.75 19 00| 20 32|11 37|6 feet.

Summit | 46 42 40| 75 15 00| | |

---- | 46 36 56| 75 13 20| | |

---------------------------+---------+----------+------+-----+-----------

======================== | | | | |

Extremity | 46 43 08| 75 40 55| | |

---- | 46 48 20| 75 39 35| | |

---- | 46 58 57| 75 27 30| | |

---------------------------+---------+----------+------+-----+

=============== | | | | |

Entrance of Fallos Ch. | 47 57 55| 75 23 45| | |

Northernmost point | 48 01 00| 75 29 15| | |

---------------------------+---------+----------+------+-----+-----------

{492}

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

Coast of Wellington and | deg ' "| deg ' "| deg '|H. M.|

=============== | | | | |

Observation Inlet |*48 02 15|C.75 29 12| 19 10|11 45|3 to 4 feet

Summit | 48 06 16| 75 42 00| | |

Extremity | 48 05 55| 75 34 35| | |

Centre peak | 48 37 40| 75 28 10| | |

Summit | 48 45 40| 75 29 35| | |

---------------------------+---------+----------+------+-----+-----------

====================== | | | | |

Summit | 49 07 20| 75 33 40| | |

---- | 50 10 52| 75 17 35| | |

---- | 50 42 02| 75 24 00| | |

---------------------------+---------+----------+------+-----+-----------

---- | 51 30 00| 75 25 00| | |

---- | 51 51 40| 75 09 30| | |

---------------------------+---------+----------+------+-----+-----------

* * * * *

{493}

TABLE IV.

------

OUTER, OR SEA COAST, OF TIERRA DEL FUEGO.

------

In order to adapt the longitudes of the places mentioned in this Table to

the meridians of Port Famine and St. Martin Cove, at Cape Horn, the

following corrections[209] have been made to Captain Fitz-Roy's

chronometrical results, _viz_:--

Townshend Harbour } { 0'11"}

Stewart Harbour } { 0 23 } to the Eastward of Captain

Doris Cove } have been placed { 0 33 } Fitz-Roy's chronometrical

March Harbour } { 1 6 } deductions.

Good Success Bay } { 2 0 }

By Captain Fitz-Roy's observations St. Martin Cove would be in long. 67deg

31' 18", which is 2' 15" to the Westward of the mean of upwards of thirty

chronometrical results from Monte Video. The difference has, therefore,

been equally divided between North Cove and St. Martin Cove; the longitude

of the latter being taken at 67deg 29' 03", and of Port Famine at 70deg

54'.

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

Sea Coast of Tierra del Fuego deg ' "| deg ' "| deg '|H. M.|

========================== | | | | |

Near the projecting pt. |*52 54 13|C.74 33 03| 23 53| 1 40| 4

Saturday Harbour | 53 11 26| 74 14 36| 24 0| 2 0| 4

West point of entrance |*53 18 40| 74 12 6| 23 56| 2 5| 4

---- |*53 34 58|C.73 34 46| | |

North point |*54 06 58|C.73 15 20| | 1 0| 4

Penguin Point | 54 28 15| 72 56 00| 24 40| 2 30| 4

Extremity | 54 30 00| 73 01 30| 25 00| |

South Easternmost | 54 37 05| 72 59 00| | |

Summit | 54 30 00| 73 01 30| | |

Island in the entrance | 54 28 00| 72 14 00| 24 30| 2 30| 4

---- |*54 13 00| | | |

---- |*54 24 26|C.72 14 46| 24 30| 2 30| 4

Summit | 54 24 44| 72 07 40| | |

South-east Peak | 54 39 48| 71 56 50| | |

Islet on N. side of Harb |*54 42 15|C.71 51 49| 24 34| 1 30| 4

Extremity | 54 56 40| 71 25 00| | |

E side of Shelter Island |*54 54 24| 71 25 05| 24 14| 2 50| 4

East Point entrance |*54 58 45| 71 05 35| 24 16| 3 0| 4

Extremity | 55 11 55| 70 47 50| | |

Summit | 55 24 30| 70 01 50| | |

---------------------------+---------+----------+------+-----+----------

{494}

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

Sea Coast of Tierra del Fuego deg ' "| deg ' "| deg '|H. M.|

========================== | | | | |

Entrance of the Basin |*55 22 35| 69 53 57| 24 4| 3 10| 4

Rocky Pt. N end of Beach |*55 21 12| 60 50 00| 24 40| 3 10| 4

Henderson Id. |*55 35 46|} 68 58 00|(Mount Beaufoy.)

---- |*55 35 54|} | | |

Middle of Bay |*55 30 50|C.68 00 23| 23 56| 3 30| 4

Head of the Cove |*55 51 19|C.67 29 03| | |

Summit |*55 58 41| 67 10 53| | |

Point at N. end of Beach |*55 17 04| 66 44 03| 23 40| 4 40| 8

Centre | 55 33 00| 66 40 03| | |

S or Boat Island, summit | 56 26 35| 63 36 20| 24 0| |

Northernmost Rock | 56 22 25| 68 36 45| | |

Centre |*55 48 54| 66 39 48| | |

Point Kinnaird | 54 57 05| 65 42 54| | |

S. side near Sandy Beach |*54 48 02|C.65 09 18| 22 42| 4 15| 9

Extremity | 54 40 35| 65 01 53| | |

---------------------------+---------+----------+------+-----+-----------

* * * * *

TABLE V.

------

COAST OF CHILE.

---------------------------+---------+----------+------+----------------

Name of | | | | TIDE

---------------------------+ | | |-----+----------

| | | |H. W.| of Flood,

---------------------------+---------+----------+------+-----+----------

| deg ' "| deg ' "| deg '|H. M.|

Sandy Point |*41 51 34|C.73 50 25| 18 33|11 15| 6

Fort Galvez |*36 41 58|C.73 03 05| 16 47| |

Cerro Alegre |*33 01 58|C.71 34 12| 15 18| |

Cumberland Bay |*33 37 36|C.78 46 04| 17 13| |

---------------------------+---------+----------+------+-----+-----------

* * * * *

{495}

TABLE OF OBSERVED OR ESTIMATED HEIGHTS OF MOUNTAINS AND PARTICULAR PARTS OF

THE SEA COAST.

Ang. denotes the height to have been ascertained by Angular Measurement;

Bar. by Barometer; and Est. by Estimation.

NORTH ATLANTIC OCEAN.

CAPE VERD ISLANDS.

FEET.

Peak at the N.W. end of San Antonio 7086 Ang.

Pico Antonio, on St. Jago 4725 Ang.

Pico of Fuego 8815 Ang.

SOUTH ATLANTIC OCEAN.

COAST OF BRAZIL.

Corcovado, at Rio de Janeiro 2330 Bar. 5 Obs.

Sugar Loaf, do 1275 Ang.

Cubatoa, at Santos (Telegraph House) 2502 Bar. 5 Obs.

City of San Paulo (Base of the Cathedral) 2444 Bar. 16 Obs.

EAST COAST OF PATAGONIA.

Cliffy Coast, near Port St. Julian 300 to 330 Est.

Mount Entrance (Santa Cruz) 356 Ang.

Cape Fairweather and the Cliffs to the Northward 300 Est.

Cape Virgins and the Cliffs to the Northward 300 Est.

{496}

STRAIT OF MAGALHAENS.

FEET.

Cape Possession 300 Est.

Table Mountain behind Cape Gregory 1500 to 2000 Est.

Point Santa Anna (Port Famine) 104 Ang.

Mount St. Philip do. 1308 Ang.

Mount Graves, North Summit (Dawson Island) 1315 Ang.

Do. South do. do. 1498 Ang.

Lomas Range, the highest part over Port San Antonio 2963 Ang.

Mount Tarn (Peak at the N.E. end) { 2602 Bar. 4 Obs.

{ 2852 Ang.

Mount Buckland, Gabriel Channel 4000 Est.

Mount Boqueron (entrance of Magdalen Channel) 3000 Est.

Mount Sarmiento (bottom of do. ) 6800 Ang.

Pyramid Hill ( do. do. ) 2500 Ang.

Cape Froward (Land behind the Morro) 2500 Est.

Cape Holland 1800 Est.

Mount Pond 2500 Est.

Mount Cross, Port Gallant { 2290 Bar.

{ 2264 Ang. 3 Obs.

Average height of the land near Sea Reach 1000 to 2500 Est.

OUTER COAST OF TIERRA DEL FUEGO.

Kater Peak, on Hermite Island 1742 Bar. 4 Obs.

Bell Mount, near Strait le Maire 4000 Est.[210]

Noir Island 600 Est.

SOUTH PACIFIC OCEAN.

WESTERN COAST OF PATAGONIA.

Mount Burney 4800 Ang.

Cape Three Points 2000 Est.

Mountain within Kelly Sound 1540 Ang.

Sugar Loaf (Marine Islands, in Holloway Sound) 1836 Ang.

Dome of St. Paul ( do. do. ) 2284 Ang.

Highest peak of Juan Fernandez (The Yungue, or Anvil) 3005 Ang.

* * * * *

{497}

MAGNETIC OBSERVATIONS,

DISCUSSED BY

MAJOR SABINE, R.A., F.R.S.

1. _Observations of the Dip._

Captain Fitz-Roy was furnished with two Dip Circles, one by Gambey, and the

other by Dollond; the latter supplied by Government, and Gambey's purchased

by himself.

Gambey's, being found to give results more accordant with each other than

Dollond's, was used at all the stations, except Rio de Janeiro. The Circle

was nine and a-half inches in diameter, and was furnished with two needles.

This instrument was, in all respects, a very superior one. It was placed

for observation on a stand, which raised it from two to three feet above

the ground. The needle was observed in eight positions, and as the readings

accorded sufficiently well with each other, their arithmetical mean has

been taken as the dip resulting from the observation. The eight positions

were as follows: 1, with the graduated face of the circle towards the east;

2, with the same towards the west. The needle was then taken out and

replaced with the ends of the axle changed, so that each end rested on a

different plane to what it did before; it was then observed, 3, with the

face of the circle towards the west, and 4, with the same to the east. The

poles were then inverted, so that the end of the needle which was before a

north pole became a south pole, and the four positions were again repeated.

The arc indicated by both ends of the needle was read in every position: an

observation of the dip consisted, consequently, of sixteen readings. In the

subjoined tabular record these are comprised in four entries, a mean being

taken of the arc read at the two extremities of the needle, and of the

positions 1 and 3, 2 and 4: 1 and 3 form the column, a; 2 and 4 the column,

a'; and the same positions, with the poles reversed, the columns a" and

a"'.

{498}

MAGNETIC DIP.

-----------+--------+-----+-----+----+---+-------------------------------

| | | | | N | Needle

| | | | | e |---------------+---------------

| | the | |er- | l |-------+-------+-------+-------

Station | Date | Sea |Therm|ver | e | a | a' | a" | a"'

-----------+--------+-----+-----+----+---+-------+-------+-------+-------

| 1831 |Feet.| deg | | |deg ' |deg ' |deg ' |deg '

Plymouth |Nov. 20{| 50 | 58 | F. | 1 |69 49 |69 06,5|69 53 |69 08

| {| 50 | 58 | F. | 2 |69 23,5|69 29,5|69 26 |69 25,5

| 1832 | | | | | | | |

Port Praya |Jan. 28{| 20 | 71 | F. | 1 |46 46,5|46 19 |46 36 |45 40

| {| 20 | 71 | F. | 2 |46 16,5|46 23,5|46 23 |46 17

| | | | | | | | |

| {| 16 | 83 | S. | | 6 18 | 6 02 | 3 27,5| 3 38

Bahia |Mar. 6 {| 16 | 83 | S. | | 7 19,5| 7 02 | 1 39 | 1 54,5

| {| 16 | 84 | S. | | 7 59 | 9 29,5| 1 08,5| 1 54

| {| 16 | 84 | S. | | 6 29 | 6 02,5| 4 11,5| 4 11

| | | | | | | | |

Rio de | {| 10 | 78 | S. | |13 42 |12 05,5|14 27 |14 05,5

Janeiro |Apr. 30{| 10 | 78 | S. | |13 02 |11 54,5|15 15,5|15 16,5

| {| 10 | 79 | S. | |14 24 |14 06 |12 04,5|13 03

| | | | | | | | |

{|Sept.5 {| 18 | 49 | F. | 1 |40 45 |42 50 |40 50 |43 42,5

Blanco Bay{| {| 18 | 49 | F. | 2 |42 34 |41 47,5|41 15 |41 57

{|Sept.19{| 18 | 67 | F. | 1 |41 28 |42 02,5|41 32,5|42 22

{| {| 18 | 67 | F. | 2 |41 48 |41 52 |41 46,5|41 51

| 1833 | | | | | | | |

{|Mar. 12{| 8 | 48 | F. | 1 |53 23 |53 27 |56 22 |51 48

Falkland {| {| 8 | 49 | F. | 2 |53 25 |53 32 |50 47 |54 45

Islands {|Mar.13 {| 8 | 50 | F. | 1 |53 08 |53 53 |53 19 |53 59

{| {| 8 | 51 | F. | 2 |53 40 |53 38 |53 27 |53 34

| | | | | | | | |

Monte Video|Nov. 25{| 10 | 84 | F. | 1 |35 10 |34 40 |35 28,5|34 40

| {| 10 | 84 | F. | 2 |34 55 |34 47,5|34 20 |34 50

| | | | | | | | |

{499}

Port Desire|Dec. 30{| 48 | 58 | F. | 1 |53 05 |52 29 |53 20 |52 22,5

| {| 48 | 58 | F. | 2 |52 45 |52 27,5|52 49 |52 30

| 1834 | | | | | | | |

Falkland |Mar. 19{| 60 | 45 | F. | 1 |53 16,5|53 21,5|52 58 |54 05

Islands | {| 60 | 45 | F. | 2 |53 40 |52 58 |53 23 |52 58

| {| 60 | 45 | F. | 1 |53 23 |52 45 |53 59 |53 08,5

| {| 60 | 45 | F. | 2 |53 19 |53 19 |53 22 |53 19

| | | | | | | | |

River Santa|May 10 {| 20 | 48 | F. | 1 |55 37 |54 37 |55 45 |54 48

Cruz | {| 20 | 48 | F. | 2 |55 30 |55 21 |55 21 |55 07

| | | | | | | | |

Port San |Dec. 24{| 8 | 62 | F. | 1 |54 32 |54 12 |54 40 |54 00

Andres | {| 8 | 62 | F. | 2 |54 19 |54 10 |54 07 |53 49

| 1835 | | | | | | | |

Port Low |Jan. 15{| 6 | 57 | F. | 1 |51 27 |50 44 |51 42 |51 00

| {| 6 | 57 | F. | 2 |51 48 |51 40 |51 10 |51 10

| | | | | | | | |

Chiloe |Jan. 26{| 10 | 66 | F. | 1 |49 12 |48 29 |49 30 |48 41

| {| 10 | 66 | F. | 2 |49 09 |49 02 |48 57 |48 51

| | | | | | | | |

Valdivia |Feb. 18{| 8 | 69 | F. | 1 |46 58 |46 18 |47 22 |46 34

| {| 8 | 69 | F. | 2 |46 56 |46 42 |46 44 |46 38

| | | | | | | | |

Concepcion |Apr. 13{| 90 | 59 | F. | 1 |43 30 |42 47 |43 47 |42 58

| {| 90 | 59 | F. | 2 |43 25 |43 15 |43 11 |43 10

| | | | | | | | |

Valparaiso |June 27{| 15 | 57 | Sg.| 1 |38 24 |37 26 |38 33,5|37 46

| {| 15 | 57 | Sg.| 2 |38 17,5|38 01,5|38 00 |37 56

| | | | | | | | |

Callao |Aug. 26{| 12 | 64 | Sg.| 1 | 6 46,5| 6 50 | 7 34,5| 7 24

| {| 12 | 64 | Sg.| 2 | 7 05 | 6 35 | 6 54,5| 7 04,5

| | | | | | | | |

Galapagos |Sept.22{| 6 | 72 | Sg.| 1 | 9 08 | 8 53,5| 8 35 | 8 30

Islands | {| 6 | 73 | Sg.| 2 | 8 29,5| 8 40,5| 8 42,5| 8 31

| | | | | | | | |

Galapagos |Oct. 16{| 8 | 70 | F. | 1 | 9 47,5| 9 41 | 9 17 | 9 13,5

Islands | {| 8 | 70 | F. | 2 | 9 24,5| 9 32,5| 9 26 | 9 27,5

| | | | | | | | |

Otaheite, {|Nov. 16{| 4 | 79 | Sg.| 1 |30 02 |30 06 |30 39,5|29 51

or Tahiti {| {| 4 | 79 | Sg.| 2 |30 21 |29 58 |30 10,5|30 13

{|Nov. 23{| 4 | 80 | Sg.| 1 |30 17,5|30 11 |30 58 |30 05,5

{| {| 4 | 80 | Sg.| 2 |30 18 |30 07,5|30 08 |30 09

-----------+--------+-----+-----+----+---+-------+-------+-------+-------

{498}

-----------+-------------------+------------------

| |

| | Place of

Station | Dip deduced. | Observation

-----------+-------------------+------------------

|deg ' deg ' |

Plymouth |69 29,1 } 69 27,6N.|Athenaeum

|69 26,1 } |

| |

Port Praya |46 20,4 } 46 20,2N.|Landing Place

|46 20,0 } |

| |

| 4 51,5 } |

Bahia | 4 28,7 } 4 55,8N.|San Antonio

| 5 07,7 } |(Dollond's Instr.)

| 5 13,5 } |

| |

Rio de |13 34,2 } 13 37,4S.|Villegagnon

Janeiro |13 52,7 ) |Island.

|13 24,5) |(Dollond's Instr.)

| |

{|42 01,9 } |

Blanco Bay{|41 53,4 } 41 54 S.|The Wells at

{|41 51,2 } | Point Johnson.

{|41 49,4 } |

| |

{|53 45 } |

Falkland {|53 07,2 } 53 30,4S.|Berkeley Sound,

Islands {|53 34,7 } |Magellan or

{|53 34,8 } |Johnson Cove.

| |

Monte Video|34 59,4 } 34 51,2S.|Rat Island.

| |

{499}

Port Desire|52 49,1 } 52 43,5S.|Spanish Ruins.

|52 37,9 } |

| |

Falkland |53 25,2 } 53 19,6S.|

Islands |53 14,7 } |Berkeley Sound,

|53 18,9 } |Port Louis.

|53 19,7 } |

| |

River Santa|55 11,7 } 55 15,7S.|Keel Point.

Cruz |55 19,7 } |

| |

Port San |54 21,0 } 54 13,6S.|Christmas

Andres |54 06,2 } |Cove.

| |

Port Low |51 13,2 } 51 20,1S.|Observation

|51 27,0 } |Islet.

| |

Chiloe |48 58 } 48 58,9S.|San Carlos,

|48 59,8 } |Pt. Arena.

| |

Valdivia |46 48 } 46 46,5S.|Corral.

|46 45 } |

| |

Concepcion |43 15,5 } 43 15,4S.|Fort

|43 15,2 } |Galvez.

| |

Valparaiso |38 02,4 } 38 03,1S.|Near Fort

|38 03,8 } |St. Antonio.

| |

Callao | 7 08,7 } 7 02,8S.|Arsenal.

| 6 56,9 } |

| |

Galapagos | 8 46,6 } 8 41,2N.|Chatham Island,

Islands | 8 35,9 } |Stephen Bay.

| |

Galapagos | 9 29,7 } 9 28,6N.|Charles

Islands | 9 27,6 } |Island.

| |

Otaheite, {|30 09,6 } 30 13,5S.|Point

or Tahiti {|30 10,6 } |Venus.

{|30 23 } |

{|30 10,6 } |

-----------+-------------------+------------------

{500}

-----------+--------+-----+-----+----+---+-------------------------------

| | | | | N | Needle

| | | | | e |---------------+---------------

| | the | |er- | l |-------+-------+-------+-------

Station | Date | Sea |Therm|ver | e | a | a' | a" | a"'

-----------+--------+-----+-----+----+---+-------+-------+-------+-------

| 1835 |Feet.| deg | | |deg ' |deg ' |deg ' |deg '

New Zealand|Dec. 23{| 10 | 63 | Sg.| 1 |59 44 |59 04,5|60 09,5|59 14

| {| 10 | 64 | Sg.| 2 |59 43,5|59 28,5|59 32,5|59 19,5

| 1836 | | | | | | | |

Sydney |Jan. 15{| 24 | 72 | Sg.| 1 |63 00,5|62 26,5|63 19 |62 35

| {| 24 | 72 | Sg.| 2 |62 55,5|62 48,5|62 53,5|62 35,5

| | | | | | | | |

Hobart Town|Feb. 6 {| 35 | 51 | Sg.| 1 |70 51,5|70 13 |71 02,5|70 15,5

| {| 35 | 51 | Sg.| 2 |70 43,5|70 27 |70 37 |70 25,5

| | | | | | | | |

King George|Mar. 8 {| 4 | 67 | Sg.| 1 |64 57,5|64 17,5|65 09 |64 25

Sound | {| 4 | 67 | Sg.| 2 |64 49,5|64 35 |64 44,5|64 33

| | | | | | | | |

Keeling |Apr. 4 {| 3 | 79 | Sg.| 1 |38 48,5|37 45,5|39 08 |38 24

Islands | {| 3 | 79 | Sg.| 2 |38 43,5|38 32 |38 35,5|38 28

| | | | | | | | |

Mauritius |May 3 {| 5 | 81 | Sg.| 1 |54 21,5|53 23 |54 41 |53 46,5

| {| 5 | 81 | Sg.| 2 |54 08,5|54 00,5|53 58 |53 47,5

| | | | | | | | |

|June 2{ | 4 | 64 | Sg.| 1 |52 53 |51 53 |53 14,5|52 22

Cape of | { | 4 | 64 | Sg.| 2 |52 40,5|52 32,5|52 34 |52 26

Good Hope |June 10{| 35 | 65 | Sg.| 1 |53 03 |52 37 |53 14 |52 27,5

| {| 35 | 65 | Sg.| 2 |52 39 |52 40 |52 38 |52 25

| | | | | | | | |

St. Helena |July 11{| 17 | 70 | Sg.| 1 |18 01 |17 18,5|18 43,5|18 10,5

| {| 17 | 70 | Sg.| 2 |18 06,5|17 48,5|17 55 |18 05,5

| | | | | | | | |

Ascension |July 21{| 15 | 72 | Sg.| 1 | 2 02,5| 2 01 | 1 22,5| 1 15,5

Island | {| 15 | 72 | Sg.| 2 | 1 25,5| 1 52 | 1 48,5| 1 26

| | | | | | | | |

Bahia |Aug. 4 {| 6 | 74 | Sg.| 1 | 5 34,5| 5 29 | 6 28 | 6 10,5

| {| 6 | 74 | Sg.| 2 | 6 01 | 5 48,5| 5 35 | 6 01,6

| | | | | | | | |

{501}

Pernambuco |Aug. 13{| 5 | 76 | F. | 1 |13 37 |13 24 |13 05 |12 52

| {| 5 | 76 | F. | 2 |13 10 |13 15 |13 15 |13 05

| | | | | | | | |

{|Sept. 1{| 18 | 80 | Sg.| 1 |46 19,5|45 22,5|45 52 |45 01

{| {| 18 | 80 | Sg.| 2 |45 42,5|45 40,5|45 47 |45 36,5

Port Praya{|Sept.2{ | 25 | 81 | Sg.| 1 |46 49,5|45 53,5|46 07,5|45 16,5

{| { | 25 | 81 | Sg.| 2 |46 04 |45 52,5|45 54,5|46 02,5

{|Sept. 3{| 50 | 80 | Sg.| 1 |45 15 |45 22 |45 48 |45 08,5

{| {| 50 | 80 | Sg.| 2 |45 42,5|45 33 |47 47,5|45 37

| | | | | | | | |

Terceira |Sept.21{| 4 | 72 | Sg.| 1 |68 39 |67 45 |68 24 |67 45,5

| {| 4 | 72 | Sg.| 2 |67 58,5|67 59 |68 14 |68 02,5

| | | | | | | | |

Falmouth |Oct. 4{| 100 | 58 | F. | 1 |69 29 |69 26 |69 16 |69 19

| {| 100 | 58 | F. | 2 |69 17 |69 06,5|69 27,5|69 15,5

| | | | | | | | |

Plymouth |Oct. 12{| 50 | 54 | Sg.| 1 |69 54 |68 59,5|69 46,5|68 40,5

| {| 50 | 54 | Sg.| 2 |69 15,5|69 09 |69 33 |69 10

| | | | | | | | |

Plymouth |Oct. 15{| 100 | 56 | Sg.| 1 |69 57 |68 54 |69 16,5|68 43

| {| 100 | 56 | Sg.| 2 |69 17 |69 02,5|69 29,5|69 11

-----------+--------+-----+-----+----+---+-------+-------+-------+-------

{500}

-----------+-------------------+------------------

| |

| | Place of

Station | Dip deduced. | Observation

-----------+-------------------+------------------

|deg ' deg ' |

New Zealand|59 33 } 59 32 S.|Paihia Islet.

|59 31 } |

| |

Sydney |62 50,2 } 62 49,4S.|Fort Macquarie.

|62 48,5 } |

| |

Hobart Town|70 35,6 } 70 34,9S.|Fort Mulgrave.

|70 34,2 } |

| |

King George|64 42,2 } 64 41,3S.|Landing Place.

Sound |64 40,5 } |

| |

Keeling |38 31,5 } 38 33,1S.|Direction Inlet.

Islands |38 34,7 } |

| |

Mauritius |54 03,1 } 54 00,8S.|Cooper Island.

|53 58,6 } |

| |

|52 35,6 } 52 34,4S.|Simon Town.

Cape of |52 33,2 } |

Good Hope |52 35,4 } 52 35,5S.|Observatory

|52 35,5 } | (outside).

| |

St. Helena |18 03,4 } 18 01,2S.|James Town.

|17 59,0 } |

| |

Ascension | 1 40,4 } 1 39,2N.|Barrack Square.

Island | 1 38,0 } |

| |

Bahia | 5 55,5 } 5 53,5N.|San Antonio.

| 5 51,5 } |

| |

{501}

Pernambuco |13 14,5 } 13 12,9N.|Arsenal.

|13 11,5 } |

| |

{|45 38,9 } |

{|45 41,6 } |Landing Place.

Port Praya{|46 01,7 } 45 46,5N.|

{|45 58,6 } |

{|45 38,4 } |Quail Island.

{|45 40,0 } |

| |

Terceira |68 08,4 } 68 06 N.|Angra.

|68 03,5 } |

| |

Falmouth |69 22,5 } 69 19,5 |Mr. Fox's.

|69 16,6 } |

| |

Plymouth |69 20,1 } 69 18,5N.|Mount Wise.

|69 16,9 } |

| |

Plymouth |69 20,1 } 69 17,6N.|Athenaeum.

|69 15 } |

-----------+-------------------+------------------

Observers:--F. Capt. FITZ-ROY. S. Lieut. SULIVAN. Sg. Mr. STEBBING

* * * * *

{502}

2. _Observations of Intensity._

The method employed by Captain Fitz-Roy to determine the variations of the

magnetic force was that of noting the time of vibration of a magnetic

cylinder suspended horizontally.

The cylinder was one which had been given by M. Hansteen, in 1826, to

Captain Phillip Parker King, R.N., and had been used by him during the

survey of the coast of South America, which he conducted from 1826 to 1830.

The apparatus in which it was vibrated, both in Captain King's and Captain

Fitz-Roy's voyages, was the well-known one of M. Hansteen.

By observations made with this cylinder on the 22d March 1826, and again on

the 24th January 1830, in the garden of the Royal Observatory at Greenwich,

it appeared that its time of performing 300 vibrations had increased from

734,45 seconds in 1826, to 775,80 seconds in 1831; or 41,35 seconds in

1,770 days. A change of such magnitude in the magnetic intensity of the

instrument employed to measure the variations of the terrestrial intensity,

and which ought itself, therefore, to be invariable, would, in the

generality of cases, have prevented any satisfactory conclusion whatsoever

being drawn from the observations. Fortunately from the nature of the

duties in which Captain King was engaged, he had occasion to return

frequently to the same anchorages, and by his extreme care to repeat

observations on every such return, he has provided a means of computing the

decrease of the intensity of the cylinder, proportioned to intervals of

time, between 1826 and 1831; and of thus introducing compensations for it,

which render the results on the whole nearly as satisfactory as if the

cylinder had preserved an uniform magnetic condition throughout.

The voyage which Captain Fitz-Roy had to perform promised to furnish few,

if any, such opportunities of examining the state of the magnetism of the

cylinder, between the departure from and the return to England; and,--as it

cannot but be extremely discouraging to officers to make observations which

they have reason to apprehend may prove unavailing from defect in the

instrument employed,--it must be regarded as exceedingly creditable to

Captain Fitz-Roy and his officers, that, with the knowledge of the {503}

change which the cylinder had undergone in the preceding voyage, they

persevered in diligently observing, and carefully recording, its time of

vibration, at most of the principal ports which they visited in their

voyage of five years' duration. Nor was it until their return to the Cape

Verd Islands, in September 1836, that they could infer, from observations

repeated at the same spot as in their outward passage in 1832, that the

cylinder had not varied in any thing like the degree that it had done in

the preceding voyage, and that the care and pains they had bestowed were

therefore likely to be recompensed by success.

This appears a fitting opportunity to remark, how much the establishment in

England of a depository for magnetic needles is needed; whence officers,

and persons desirous of making such observations, might be supplied with

instruments, which had been kept a sufficient time to have attained their

permanent magnetic state, and had been examined from time to time to prove

that they had done so. The correction for temperature should be ascertained

for each needle, and given with it; as well as the time of vibration (or

whatever else constituted the measure of intensity,--as, for example, the

angle of deflection in Mr. Lloyd's statical needles,)--observed at the spot

which should be selected as most suitable for a point of general

comparison; and the observations should be repeated at the same spot on the

return of the needle. The want of such an establishment has long been

greatly felt; and opportunities, where nothing was wanting but proper

instruments, have been lost in consequence, where determinations of great

value might have been obtained, in parts of the world of the highest

magnetic interest, and where such opportunities are of rare occurrence.

The corrections necessary to render the times of vibration at the different

stations strictly comparable with each other, are as follows.

1st, For the rate of the chronometer.

2d, For the temperature of the needle.

3d, For the arc of vibration.

4th, For any change in the magnetic condition of the cylinder.

In extensive voyages, the last-named correction, or that for the change in

the cylinder itself, is the one which requires principal consideration. The

corrections for temperature, and for the arc, on the first of which

particularly much stress has sometimes been {504} laid, are important when

extreme accuracy is sought; as for example, in comparing the force at

stations which have served as the unities of different observers: their

effect is, however, of little moment in observations which include great

differences of the terrestrial intensity. But when the magnetic condition

of the needle has varied, and interpolation becomes necessary, the

instances are rare in which it can be done with entire satisfaction.

The time of vibration of this cylinder at Plymouth, with corrections

applied for the chronometer's rate, the temperature, and the arc, was, in

December 1831, 770,8 seconds, with a dip of 69deg 27',6, and in October

1836, 777,3 seconds with a dip of 69deg 17',5. The difference in its

magnetic state, at the two periods, is shown by the squares of the times of

vibration multiplied by the cosine of the dip observed at the respective

periods. This makes known what the time of vibration of the same cylinder

would have been, had it been free to move in the direction of the

dipping-needle, instead of being suspended horizontally; and, consequently,

if it had been acted upon by the total magnetic intensity, instead of by

the horizontal component only. It is here assumed that the total

terrestrial intensity is constant at the same place. This is doubtless not

strictly true; but the amount of the change must be too small to require

consideration in the period occupied by Captain Fitz-Roy's observations.

The horizontal component must, however, necessarily vary with the changes

in the dip: and it is, therefore, from the time of vibration in the

direction of the dipping-needle, and not from the time of horizontal

vibration, that the change, or otherwise, in the magnetism of the needle is

to be inferred. We find, then, the equivalent time of vibration of this

cylinder in the direction of the dipping-needle to have been 456,4 seconds

in December 1831, and 462,2 seconds in October 1836; showing a difference

of 5,8 seconds in fifty-eight months. If we compare this amount with the

far greater loss of intensity sustained by this cylinder in the preceding

voyage, it seems a probable supposition that, at the commencement of

Captain Fitz-Roy's voyage, the cylinder had nearly attained its permanent

magnetic state; and that its further loss of magnetism, occasioning an

increase of 5,8 seconds in the time of vibration, took place in the early

part of the voyage: supposing the loss to have been progressive, and not

sudden, as from accidents, of which the observations give no indications.

{505} Consistently with this supposition, the loss has been distributed

through the first half, or twenty-nine months, of this voyage, in the

proportion of three-tenths of a second per month in the first ten months,

commencing December 1st 1831; two-tenths per month in the next nine months;

and one-tenth per month in the remaining nine months. In the last

twenty-nine months of the voyage, the intensity of the cylinder is supposed

to have been uniform, and the same which it was found to possess on the

return to England in 1836.

It is satisfactory that, with this compensation, the observations at Port

Praya, in January 1832, and in September 1836, assign almost identically

the same relative magnetic intensity to that station.

The correction for temperature for this cylinder not having been previously

examined, I received it from Captain Fitz-Roy for that purpose, and made

with it the following observations. The cylinder, in its own apparatus, was

placed in a large earthen jar, glazed at the top, and standing in a larger

earthen vessel, into which warm water could be poured at pleasure, and the

cylinder was then vibrated alternately in heated air and in air of the

natural temperature. These experiments were made at Tortington, in Sussex.

{506}

+---------+-------+----------+----------+------------+

+---------+-------+----------+----------+------------+

| | |h. m. | deg | s |

| {|June 12|11 50 A.M.| 12,00 | 774,91 |

| {| -- | 0 12 P.M.| 12,00 | 775,37 |

| {| -- | 0 34 P.M.| 12,00 | 775,71 |

| {| -- | 1 58 P.M.| 31,65 | 777,31 |

| Exp. 1 {| -- | 2 21 P.M.| 32,20 | 777,09 |

| {| -- | 2 42 P.M.| 31,30 | 776,86 |

| {| -- | 4 00 P.M.| 15,45 | 774,00 |

| {| -- | 4 22 P.M.| 15,80 | 774,25 |

| {| -- | 4 44 P.M.| 15,70 | 774,23 |

| | | | | |

| {|June 13|10 49 A.M.| 14,90 | 773,77 |

| {| -- |11 16 A.M.| 15,10 | 773,37 |

| Exp. 2 {| -- | 0 20 P.M.| 34,80 | 775,94 |

| {| -- | 0 42 P.M.| 36,55 | 775,89 |

| {| -- | 1 30 P.M.| 17,70 | 774,06 |

| {| -- | 1 52 P.M.| 15,90 | 774,11 |

+---------+-------+----------+----------+------------+

+---------+------------------------------------------------------ -+

| | |

+---------+------------------------------------------------------ -+

| | |

| {|} h. m. deg s |

| {|} Mean, 0 12 P.M. 12,0 775,33 Natural Temperature. |

| {|} |

| Exp. 1 {|} Mean, 2 20 P.M. 31,72 777,09 Heated Air. |

| {|} |

| {|} Mean, 4 22 P.M. 15,65 774,16 Natural Temperature. |

| {|} |

| | |

| {|} Mean, 11 02 A.M. 15,0 773,57 Natural Temperature. |

| {|} |

| Exp. 2 {|} Mean, 0 31 P.M. 35,7 775,92 Heated Air. |

| {|} |

| {|} Mean, 1 41 P.M. 16,8 774,08 Natural Temperature. |

| {|} |

+---------+--------------------------------------------------------+

In the first Experiment,

T=777,09; T' 774.74; t=103deg,4 Faht.; and t'=63deg,1 Faht.

In the second Experiment,

T=775,92; T' 773,83; t=112deg,3 Faht.; and t'=67deg,8 Faht.

The first Experiment gives (T-T')/T(t-t') = 2.35/(777,09x40,3)=.000075.

The second Experiment gives (T-T')/T(t-t') = 2,09/(775,92x44,5)=.000061.

{507}

Whence the formula T'=T [1 x 0.000068 (60deg-t)], in which T is the time of

vibration at any station, t, the temperature of the cylinder in degrees of

Fahrenheit, and T' is the equivalent time at a standard temperature of

60deg. The thermometer was noted at the beginning and ending of every set

of vibrations, and was always placed in the box with the cylinder.

* * * * *

At all Captain Fitz-Roy's stations the apparatus was placed for observation

on a stand, which raised it from two to three feet above the ground,

thereby rendering the cylinder somewhat less liable to be disturbed by

local influences: it was not furnished with a means of examining the strict

horizontality of the cylinder, that improvement having been introduced into

M. Hansteen's apparatus at a later period. On this point Captain Fitz-Roy

remarks: "A small leaden tripod was used as a stand, whose upper surface

was adjusted by a small spirit-level--or roughly by the trough of an

artificial horizon, filled with mercury. Upon the leaden stand the box

containing the needle was adjusted by its foot-screws, so that the

suspending fibre of silk hung centrally in the wooden tube, the needle's

centre being over that of the graduated circle, and the needle itself near,

but not touching, the bottom of the box. The needle was not always strictly

parallel to the bottom of the box, nor strictly horizontal, because I would

not move the brass stirrup in which it was suspended, but its deviation

from strict horizontality _never_ exceeded two degrees, and was seldom

nearly so much."

The time of completing every tenth vibration was recorded. The time of

performing 300 vibrations is deduced from a mean generally of seven partial

results: _i.e._ from the 0th to the 300th; 10th to the 310th; and so on, to

the 60th and 360th vibrations; the commencing vibration being always at an

arc of 20deg. In a very few instances the number of vibrations observed,

after the commencing arc of 20deg, was less than 360; in such cases the

first vibration after the arc had become 20deg has still been taken as the

commencing one, though previous ones may have been recorded; it being kept

strictly in view, to obtain the relative time of vibration in arcs as

nearly the same as possible, and not exceeding 20deg as the initial. The

arc was reduced to 10deg generally about the 100th vibration; and one

thousandth of the time of vibration has been taken throughout the series as

the correction to infinitely small arcs. {508}

The object of noting the time of every tenth vibration is to check errors

in the counting, which will sometimes occur in the course of the 360,

particularly with the very short and quick-moving needles of M. Hansteen's

very portable apparatus, and at stations of low dip, where the horizontal

force is greatest, and the needle consequently moves most quickly. Several

such mistakes evidently occurred. When the time of completing every

supposed tenth vibration is observed with tolerable exactness, and the

duration of each pair of vibrations decidedly exceeds any irregularity of

probable occurrence, apart from miscounting the number of vibrations, such

mistakes can be discovered with ease, and rectified with certainty. This

has been done in every case where no doubt could exist of a mistake of the

kind having occurred; such as when all the intervals are of nearly equal

duration, with one or two exceptions, which differ as much as three or four

seconds from the general body. There are two stations, however, Callao and

Keeling Islands, where the rectification is not so clear, or the true

result so obvious. At Callao there are three series of horizontal

intensities, each of forty observed intervals, which should be of ten

vibrations each. Several of these intervals are between 17,5 and 18,5

seconds, and several others between 20,5 and 21,5 seconds. These can hardly

represent an equal number of vibrations, because the difference between

them is greater than can easily be supposed due to any uncertainty in

seizing the particular beat of the chronometer at which the vibration was

completed; it is, moreover, about the time that would be occupied by two

vibrations more or less. The question then arises, do the longer intervals

represent 12, and the shorter 10 vibrations, or do the longer represent 10,

and the shorter 8? In the former supposition the intensity at Callao would

be about 1.01 (Paris = 1.348): in the latter about 0.75. The difference

shews how great an error would be risked by either assumption. If we take a

mean of all the intervals as they stand, the amount of error risked would

be certainly lessened; but we should assuredly not have the true time of

three hundred vibrations, except on one supposition: namely, that the

irregularities in question are not errors in estimating the number of

vibrations, but that each interval really represented an equal number, and

that some unusual and accidental cause occasioned the needle to differ so

greatly in successive intervals. But this {509} supposition would imply a

disturbing cause vitiating the series as a measure of the magnetic

intensity at the station. I have not ventured, therefore, to draw any

conclusion from these observations, farther than to notice, as above, the

limits within which, in either of the two first suppositions, the intensity

would fall.

A nearly similar reasoning applies to the observations at Keeling Islands;

of three series, one is decidedly so irregular, that no inference could be

drawn from it; in the two other series the irregularities are neither so

frequent, nor so large: my general impression (in the uncertainty created

by the irregularity of the first series), is, that the majority of the

intervals are of twelve vibrations, and not of ten: if of twelve, the

intensity would be about 1,21; if of ten, about 0,85.

The inconvenience of the rapid motion of the needle, occasioned, at one

part of the voyage, the practice to be discontinued of observing every

tenth vibration, and every twentieth was substituted. This no doubt

relieved the perplexity in which the observer occasionally found himself,

in having to observe, and record, and be prepared again to observe, at

every twenty seconds or less, and so far the change enabled him to observe

better. But still, the disadvantage remains, in so quick moving a needle,

that if a mistake of two vibrations is made, the difference of time

occasioned is not of so marked and decided a character as to be at all

times at once distinguished. It is of much more importance that there

should be no miscount of the vibrations, than that the times should be

recorded correctly to the fraction of a second. It is only the earlier and

later times that are finally influential; but every undetected error in the

number of vibrations falls with its whole weight upon the result.

The occasional discrepancies in the results of the same, or of different,

observers, or on the same, or on different, days, which are seen in the

subjoined table, are not, I believe, traceable to the source I have been

discussing, nor apparently to any other than an actual difference in the

time of the cylinder performing its vibration. A mean has been taken as the

result at each station, except at St. Helena, where the discrepancy on the

11th and 13th of July was so considerable, that it has been thought more

satisfactory to collect the observations of each day into separate results.

The subjoined table comprises the result of each observation, {510} and the

general results deduced for each station. The column entitled "Time" is

that of 300 vibrations; and the "Corrected Time" is the mean of these,

corrected for the rate of the chronometer and the arc, and reduced to an

average temperature of 60deg. The dips are those observed by Captain

Fitz-Roy; except at Port Famine, where, as Captain Fitz-Roy did not

observe, it has been supplied from Captain King's observations; and at

Coquimbo, where, for the purpose of computing the intensity, it has been

supplied by estimation from the other geographic positions on this coast,

at which Captain Fitz-Roy observed the dip. In the column showing the time

of vibration as a dipping-needle at Plymouth corresponding to the periods

of observation at the several stations, the compensations have been

introduced for the variation in the intensity of the cylinder, agreeably to

what has been said above on that subject. The two final columns exhibit the

values of the total magnetic intensity at the different stations derived

from these observations. In the first of the two columns, the values are

given relatively to the force at Plymouth, considered as unity; and in the

second column, relatively to the force at Plymouth, expressed by 1.375; for

the purpose of exhibiting Captain Fitz-Roy's results in direct comparison

with the determinations of continental observers, who have taken Paris as

their basis, giving the force at Paris the arbitrary expression of 1.3482.

I have taken the ratio of the force at Plymouth to that at Paris to be as

1.375 to 1.348, which I believe will prove a very near approximation; it is

that which results from Captain Fitz-Roy's observations at Plymouth, in

October 1836 (page 17), and mine, at Tortington, in Sussex, in June 1837

(page 10): the dip at Tortington, at the period in question being 68deg

57', and the intensity, compared with Paris, through the medium of London,

1.368. {511}

+--------------------+-------+------+--------+------+---------+---------+

| | | | | | | |

+--------------------+-------+------+--------+------+---------+---------+

| | 1831 | s. | s. | deg | | s. |

| Plymouth |Dec. 1|770,79| -3,0 | 50 | Kg. | 770,6 |

| | 1832 | | | | | |

| {|Jan. 27|600,17| -6,4 | 83 | F. }| 600,1 |

| Port Praya {| -- 27|604,58| -6,4 | 76 | K. }| |

| {| -- 28|598,33| -6,4 | 75 | F. }| |

| {| -- 31|602,19| -6,4 | 85 | K. }| |

| {|Feb. 1|602,50| -6,4 | 85 | F. }| |

| | | | | | | |

| Rio de Janeiro |May 1|582,78| -4,3 | 82 | S. | 581,3 |

| | | | | | | |

| Blanco Bay {|Sept.21|592,33| 0,0 | 68 | F. }| 591,9 |

| {| -- 21|593,34| 0,0 | 68 | F. }| |

| | 1833 | | | | | |

| {|Mar. 12|603,22| +1,5 | 50 | F. }| |

| Falkland Islands, {| -- 14|604,56| +1,5 | 63 | F. }| 603,0 |

| Magellan Cove {| -- 15|603,12| +1,6 | 55 | F. }| |

| {| -- 15|603,40| +1,6 | 64 | F. }| |

| | | | | | | |

| Monte Video {|Nov. 25|583,93| +7,1 | 90 | F. }| 581,9 |

| {|-- 25|583,61| +7,1 | 90 | F. }| |

| | | | | | | |

| Port Desire {|Dec. 29|597,68| +3,9 | 62 | F. }| 597,1 |

| {| -- 29|597,98| +3,9 | 62 | F. }| |

| | 1834 | | | | | |

| |Mar. 26|603,10| +5,0 | 60 | K. }| |

| Falkland Islands {| -- 26|598,72| +5,0 | 60 | K. }| 595,9 |

| Port Louis {| -- 26|596,36| +5,0 | 60 | K. }| |

| {| -- 26|590,29| +5,0 | 60 | K. }| |

| {| -- 26|594,20| +5,0 | 61 | K. }| |

+--------------------+-------+------+--------+------+---------+---------+

+---------------------+--------+--------------------+------------+

| | |---------+----------+-----+------+

| Station. | Dip |Station. | Plymouth.| 1. | 2. |

+---------------------+--------+---------+----------+-----+------+

| | deg ' | s. | s. | | |

| Plymouth |69 27,6 | 456,4 | 456,4 |1,000|1,375 |

| | | | | | |

| {|46 20,2 | 498,8 | 457,0 |0,839|1,154 |

| Port Praya {| | | | | |

| {| | | | | |

| | | | | | |

| Rio de Janeiro |13 37,8 | 573,1 | 457,9 |0,638|0,878 |

| | | | | | |

| Blanco Bay {|41 54 | 510,7 | 459,4 |0,810|1,113 |

| {| | | | | |

| | | | | | |

| {| | | | | |

| Falkland Islands, {|53 30,4 | 465,0 | 460,6 |0,981|1,349 |

| Magellan Cove {| | | | | |

| {| | | | | |

| | | | | | |

| Monte Video {|34 51,2 | 527,1 | 461,8 |0,767|1,055 |

| {| | | | | |

| | | | | | |

| Port Desire {|52 43,5 | 464,7 | 461,9 |0,988|1,359 |

| {| | | | | |

| | | | | | |

| Falkland Islands {|53 19,6 | 460,5 | 462,1 |1,007|1,385 |

| Port Louis {| | | | | |

| {| | | | | |

+---------------------+--------+---------+----------+-----+------+

{512}

+--------------------+-------+------+--------+------+---------+---------+

| | | | | | | |

+--------------------+-------+------+--------+------+---------+---------+

| | 1831 | s. | s. | deg | | s. |

| {|May 10|601,67| +8,0 | 53 | K. }| |

| R. Santa Cruz {| -- 10|601,72| +8,0 | 54 | St. }| 601,1 |

| {| -- 10|601,03| +8,0 | 50 | St. }| |

| | | | | | | |

| Port Famine {|June 4|613,25| +6,0 | 70 | S. }| 612,6 |

| {| -- 4|614,03| +6,0 | 70 | S. }| |

| | | | | | | |

| Chiloe {|Dec. 10|586,31| +9,2 | 62 | K. }| 586,0 |

| {| -- 10|587,14| +9,2 | 62 | K. }| |

| | 1835 | | | | | |

| Port Low {|Jan. 15|587,14| +8,8 | 56 | K. }| 588,7 |

| {| -- 15|591,16| +8,8 | 56 | K. }| |

| | | | | | | |

| Valdivia {|Feb. 19|587,67| +8,0 | 60 | K. }| 588,7 |

| {| -- 19|591,01| +8,0 | 61 | K. }| |

| | | | | | | |

| {|Apr. 13|584,63| +10,5 | 65 | K. }| |

| Concepcion {| -- 13|585,30| +8,6 | 65 | K. }| 583,1 |

| {| -- 14|584,94| +8,6 | 64 | K. }| |

| {| -- 14|581,03| +8,6 | 64 | K. }| |

| | | | | | | |

| Coquimbo {|June 4|566,81| +7,6 | 64 | K. }| 565,8 |

| {| -- 4|566,37| +7,6 | 64 | K. }| |

| | | | | | | |

| Galapagos Islands,{|Oct. 16|529,66| -0,4 | 88 | St. }| 527,9 |

| Charles Island {| -- 16|529,21| -0,4 | 88 | St. }| |

| | | | | | | |

| {|Nov. 16|580,33| +6,0 | 91 | K. }| |

| Otaheite, {| -- 16|580,66| +6,0 | 93 | K. }| 578,4 |

| or Tahiti} {| -- 23|578,44| +6,0 | 85 | K. }| |

| {| -- 23|581,00| +6,0 | 85 | K. }| |

+--------------------+-------+------+--------+------+---------+---------+

+---------------------+--------+--------------------+------------+

| | |---------+----------+-----+------+

| Station. | Dip |Station. | Plymouth.| 1. | 2. |

+---------------------+--------+---------+----------+-----+------+

| | deg ' | s. | s. | | |

| {| | | | | |

| R. Santa Cruz {| 55 15,7| 454,0 | 462,2 |1,037|1,425 |

| {| | | | | |

| | | | | | |

| Port Famine {| 59 52,6| 434,0 | 462,2 |1,136|1,560 |

| {| | | | | |

| | | | | | |

| Chiloe {| 48 58,9| 474,7 | 462,2 |0,948|1,304 |

| {| | | | | |

| | | | | | |

| Port Low {| 51 20,1| 465,3 | 462,2 |0,964|1,260 |

| {| | | | | |

| | | | | | |

| Valdivia {| 46 46,5| 487,2 | 462,2 |0,900|1,238 |

| {| | | | | |

| | | | | | |

| {| | | | | |

| Concepcion {| 43 15,4| 497,7 | 462,2 |0,863|1,186 |

| {| | | | | |

| | | | | | |

| Coquimbo {| 34 20 | 514,2 | 462,2 |0,808|1,111 |

| {| | | | | |

| | | | | | |

| Galapagos Islands, {| 9 28,6| 524,2 | 462,2 |0,777|1,069 |

| Charles Island {| | | | | |

| | | | | | |

| {| | | | | |

| Otaheite, {| 30 13,5| 537,6 | 462,2 |0,739|1,017 |

| or Tahiti} {| | | | | |

| {| | | | | |

+---------------------+--------+---------+----------+-----+------+

{513}

+--------------------+-------+------+--------+------+---------+---------+

| | | | | | | |

+--------------------+-------+------+--------+------+---------+---------+

| | 1835 | s. | s. | deg | | s. |

| New Zealand {|Dec. 22|604,76| +7,8 | 80 | K. }| 603,6 |

| {| -- 22|605,37| +7,8 | 80 | K. }| |

| | 1836 | | | | | |

| {|Jan. 14|620,63| -5,4 | 78 | S. }| |

| Sydney {| -- 14|619,83| -5,4 | 82 | S. }| 617,9 |

| {| -- 22|618,14| -5,8 | 86 | K. }| |

| {| -- 22|619,21| -5,8 | 87 | K. }| |

| | | | | | | |

| Hobart Town {|Feb. 6|698,63| +2,3 | 65 | S. }| 697,4 |

| {| -- 6|698,13| +2,3 | 65 | S. }| |

| | | | | | | |

| King George Sound {|Mar. 7|634,17| -5,6 | 72 | S. }| 634,1 |

| {| -- 10|636,71| +2,4 | 80 | S. }| |

| | | | | | | |

| {|May 3|647,95| -9,2 | 87 | K. }| |

| Mauritius {| -- 3|650,79| -9,2 | 94 | K. }| 647,7 |

| {| -- 3|650,37| -9,2 | 94 | K. }| |

| | | | | | | |

| {|June 1|691,13| -7,2 | 68 | S. }| |

| Cape of Good Hope {| -- 1|691,42| -7,2 | 69 | S. }| 690,6 |

| {| -- 10|691,62| +0,4 | 61 | F. }| |

| {| -- 10|692,00| +0,4 | 63 | F. }| |

| | | | | | | |

| {|July 11|612,90| -8,0 | 78 | S. }| |

| St. Helena {| -- 11|615,30| -8,0 | 79 | St. }| 613,2 |

| {| -- 11|615,40| -8,0 | 78 | S. }| |

| | | | | | | |

| {| -- 13|604,69| -8,0 | 76 | S. }| |

| St. Helena {| -- 13|605,23| -8,0 | 77 | S. }| 602,9 |

| {| -- 13|602,34| -8,0 | 72 | S. }| |

| | | | | | | |

| {|July 21|581,58| -9,4 | 75 | S. }| |

| Ascension {| -- 21|581,31| -9,4 | 75 | S. }| 580,2 |

| {| -- 21|581,09| -9,4 | 75 | S. }| |

| | | | | | | |

| {|Aug. 3|583,78| -9,4 | 75 | S. }| |

| Bahia {| -- 3|583,26| -9,4 | 75 | S. }| 582,3 |

| {| -- 4|583,13| -9,4 | 79 | S. }| |

| {| -- 4|583,89| -9,4 | 79 | S. }| |

+--------------------+-------+------+--------+------+---------+---------+

+---------------------+--------+--------------------+------------+

| | |---------+----------+-----+------+

| Station. | Dip |Station. | Plymouth.| 1. | 2. |

+---------------------+--------+---------+----------+-----+------+

| | deg ' | s. | s. | | |

| New Zealand {| 59 32,0| 429,8 | 462,2 |1,157|1,591 |

| {| | | | | |

| | | | | | |

| {| | | | | |

| Sydney {| 62 49,4| 417,6 | 462,2 |1,225|1,685 |

| {| | | | | |

| | | | | | |

| Hobart Town {| 70 34,9| 402,1 | 462,2 |1,321|1,817 |

| {| | | | | |

| | | | | | |

| King George Sound {| 64 41,3| 414,6 | 462,2 |1,243|1,709 |

| {| | | | | |

| | | | | | |

| {| | | | | |

| Mauritius {| 54 00,8| 496,5 | 462,2 |0,867|1,192 |

| {| | | | | |

| | | | | | |

| {| | | | | |

| Cape of Good Hope {| 52 35,0| 538,4 | 462,2 |0,737|1,014 |

| {| | | | | |

| | | | | | |

| {| | | | | |

| St. Helena {| 18 01,2| 598,0 | 462,2 |0,598|0,822 |

| {| | | | | |

| | | | | | |

| {| | | | | |

| St. Helena {| 18 01,2| 587,9 | 462,2 |0,618|0,850 |

| {| | | | | |

| | | | | | |

| {| | | | | |

| Ascension {| 1 39,2| 580,1 | 462,2 |0,635|0,873 |

| {| | | | | |

| | | | | | |

| {| | | | | |

| Bahia {| 5 53,5| 580,7 | 462,2 |0,633|0,871 |

| {| | | | | |

+---------------------+--------+---------+----------+-----+------+

{514}

+--------------------+-------+------+--------+------+---------+---------+

| | | | | | | |

+--------------------+-------+------+--------+------+---------+---------+

| | | s. | s. | deg | | s. |

| {|Aug. 13|576,12| -9.2 | 80 | S. }| |

| Pernambuco {| -- 13|576,00| -9.2 | 81 | S. }| 574.5 |

| {| -- 17|575,96| -9.2 | 85 | S. }| |

| {| -- 17|575,71| -9.2 | 87 | S. }| |

| | | | | | | |

| {|Sept. 1|603,13| -9.8 | 91 | S. }| |

| Port Praya {| -- 1|602,84| -9.8 | 92 | S. }| 603,4 |

| {| -- 1|607,63| -9.8 | 91 | S. }| |

| {| -- 1|607,49| -9.8 | 89 | S. }| |

| | | | | | | |

| Terceira {|Sept.21|736,73| -9.2 | 77 | S. }| 735,3 |

| {| -- 21|737,01| -9.2 | 77 | S. }| |

| | | | | | | |

| {|Oct. 15|778,10| +5.0 | 63 | Ss. }| |

| Plymouth {| -- 15|778,26| +5.0 | 64 | Ss. }| 777,3 |

| {| -- 15|778,65| +5.0 | 64 | Ss. }| |

+--------------------+-------+------+--------+------+---------+---------+

+---------------------+--------+--------------------+------------+

| | |---------+----------+-----+------+

| Station. | Dip |Station. | Plymouth.| 1. | 2. |

+---------------------+--------+---------+----------+-----+------+

| | deg ' | s. | s. | | |

| {| | | | | |

| Pernambuco {| 13 12,9| 566,8 | 462,2 |0,665|0,914 |

| {| | | | | |

| | | | | | |

| {| | | | | |

| Port Praya {| 45 46,5| 503,9 | 462,2 |0,841|1,157 |

| {| | | | | |

| | | | | | |

| Terceira {| 68 06 | 449,1 | 462,2 |1,059|1,457 |

| {| | | | | |

| | | | | | |

| {| | | | | |

| Plymouth {| 69 17,5| 462,2 | 462,2 |1,000|1,375 |

| {| | | | | |

+---------------------+--------+---------+----------+-----+------+

Observers:--F. Captain Fitz-Roy. Ss. Mr. J.L. Stokes. Kg. Capt. King.

S. Lieut. Sulivan. St. Mr. P.B. Stewart. K. Mr. P.G. King.

* * * * *

{515}

3. _Captain King's Observations of Dip and Intensity._

Captain King, having hitherto made known his observations with the same

cylinder in the years 1826 to 1830 only by communicating them to M.

Hansteen, from whom he received the apparatus, has now given permission to

Captain Fitz-Roy to publish them with his own. I have already noticed the

great loss of magnetism which took place in this cylinder during Captain

King's voyage, and the care with which that officer availed himself of

every opportunity of ascertaining, by direct observation, the proportion of

the loss sustained in separate portions of the voyage. There are twelve

stations of observation on the east and west coasts of South America,

besides three stations in ports of the Atlantic on the outward voyage. By

the practice of repeating observations at the same station at distant

intervals, the South American stations are so linked together and

connected, that by adopting a method similar to that used in determining

longitudes by means of chronometers, we may compute the intensity at all

the South American stations referred to and dependent on the force at Rio

de Janeiro; regarding Rio in the same light as a first meridian is

considered in determinations of longitude. We may then make Rio the means

of connecting the whole series with Europe; for which it is remarkably well

suited, the intensity there having been determined, independently of

Captain King, by four observers of different nations, whose results are

extremely accordant.

The dip observations of Captain King were communicated, in occasional

correspondence during the voyage, to M. Hansteen, who computed them by

Mayer's formula, and arranged them in a table, of which a copy was given by

Captain King to Captain Fitz-Roy, and is printed in the next page. At some

of the stations Captain Fitz-Roy also observed the dip in the subsequent

voyage, and, as will be seen, the results of the two observers sometimes

differ considerably. This may have been caused, either by instrumental or

other error of observation, or by actual differences of dip existing in

different localities at the same station.

* * * * *

{516}

DIPS, _observed by_ Capt. P. P. King, 1826 to 1831.

+------------------+-------+---------------------+---------------------+

| | |----------+----------+----------+----------+

| Station. |Needle.| a | a' | a" | a"' |

+------------------+-------+----------+----------+----------+----------+

| | | deg ' | deg ' | deg ' | deg ' |

| Rio de Janeiro {| 1 | 15 58,5 | 13 02,4 | 15 05,7 | 13 18,0 |

| {| 2 | 14 39,4 | 12 30,4 | 14 49,0 | 13 07,3 |

| | | | | | |

| {| 1 | 22 54,1 | 24 04,7 | 21 55,6 | 22 46,0 |

| Sta. Catharina {| 2 | 23 22,8 | 20 32,3 | 23 34,2 | 21 00,7 |

| {| 3 | 21 17,8 | 21 08,5 | 23 26,2 | 22 57,2 |

| | | | | | |

| {| 1 | 36 48,4 | 37 49,3 | 35 25,4 | 37 26,9 |

| Monte Video {| 2 | 37 17,2 | 34 53,8 | 37 17,1 | 34 37,4 |

| {| 3 | 36 36,1 | 35 10,3 | 37 12,4 | 36 13,2 |

| | | | | | |

| {| 1 | 64 41,7 | 52 42,6 | 65 51,2 | 54 54,0 |

| Port Famine {| 2 | 60 41,9 | 59 32,2 | 60 32,1 | 59 33,6 |

| {| 3 | 60 03,9 | 58 43,4 | 60 35,5 | 59 37,5 |

| | | | | | |

| {| 1 | 41 09,9 | 30 50,9 | 41 04,6 | 31 32,6 |

| Gorriti {| 2 | 36 29,2 | 33 26,4 | 35 17,1 | 34 02,7 |

| {| 3 | 34 52,3 | 34 18,5 | 36 06,9 | 35 01,3 |

| | | | | | |

| Sea Bear Bay | 1 | 58 26,5 | 47 53,8 | 60 34,8 | 47 53,4 |

| | | | | | |

| {| 1 | 65 24,7 | 54 23,8 | 65 47,7 | 54 43,6 |

| St. Martin Cove {| 2 | 60 25,6 | 59 28,3 | 59 49,9 | 58 48,6 |

| {| 3 | 59 48,9 | 58 40,7 | 60 43,4 | 59 53,3 |

| | | | | | |

| {| 1 | 54 23,9 | 45 38,3 | 56 19,2 | 45 11,1 |

| Chiloe {| 2 | 50 24,0 | 49 12,9 | 50 28,4 | 48 29,6 |

| {| 3 | 49 43,9 | 48 48,3 | 51 24,5 | 50 02,2 |

| | | | | | |

| {| 1 | 43 04,5 | 33 59,9 | 44 38,8 | 34 54,6 |

| Valparaiso {| 2 | 40 48,2 | 40 49,7 | 40 53,7 | 41 09,7 |

| {| 3 | 40 54,9 | 40 45,4 | 40 49,8 | 41 16,7 |

| | | | | | |

| {| 1 | 50 22,7 | 39 16,0 | 51 08,2 | 40 03,2 |

| Juan Fernandez {| 2 | 44 19,3 | 45 57,6 | 43 45,8 | 46 13,7 |

| {| 3 | 45 50,4 | 45 07,9 | 44 34,8 | 43 25,7 |

| | | | | | |

| Talcahuano | -- | -- | -- | -- | -- |

+------------------+-------+----------+----------+----------+----------+

Narrative of the surveying voyages of His Majesty's ships Adventure and Beagle, between the years 1826 and 1836, Vol. 1 [of 3] · 第 24 / 26 章