A Voyage of Discovery and Research in the Southern and Antarctic Regions/Volume 1/Chapter 10
CHAPTER X.
CHAPTER X.
1841.
March 9.In the instructions drawn up for my guidance by the Committee of Physics of the Royal Society, it is stated, that "M. Gauss, from theoretical considerations, has recently assigned a probable position in lat. 66° S. and long. 146° E. to the Southern Magnetic Pole, denying the existence of two poles of the same name, in either hemisphere, which, as he justly remarks, would entail the necessity of admitting also a third point, having the chief characteristics of such a pole intermediate between them;" and again, "it is not improbable that the point indicated by M. Gauss will prove accessible; at all events it cannot but be approachable sufficiently near to test by the convergence of meridians the truth of the indication; and as his theory gives within very moderate limits of error the true place of the northern pole, and otherwise represents the magnetic elements in every explored region with considerable approximation, it is but reasonable to recommend this as a distinct point to be decided;" and although our researches had proved that the result of M. Gauss's theoretical considerations was not so correct with respect to the situation of the South as it was to that of the North Magnetic Pole, probably owing to the want of a sufficient number of trustworthy observations from which to draw his deductions; and although we knew the true position of the South Magnetic Pole to be nearly in 76° instead of 66° S., yet as observations at the point indicated by M. Gauss might prove to be of more than ordinary magnetic interest, I determined to devote a few days to endeavour to approach it as nearly as possible, although, from the very late period of the season, I could not entertain the smallest hope of attaining to the spot itself; nor was it of so much importance to do so now, as both the American and French expeditions had at a more favourable period of the season made magnetic observations in its neighbourhood, concurring to show that the Magnetic Pole is situated much further south than he had supposed.
The wind was blowing so strong from the northward, with a high sea running, that we could hardly maintain our ground; we had constant snow and thick weather, but were fortunately in a space more clear of bergs and loose ice than usual, so that we felt ourselves to be in a position of comparative comfort and security, at noon we were in lat. 64° 20′ S., long. 164° 24′ E.
In the afternoon a shoal of porpoises, several white and many blue petrels and Cape pigeons were seen, as were also two whales. The snow ceased, the weather became clear, and as we approached the pack a strong blink indicated its position before March 10.dark; but we stood on through the night until 3.30 a.m., when, meeting with broad streams of ice, consisting of very heavy pieces, and many bergs, we wore and stood off again, our object now being merely to contend, as well as our dull sailing ships could do against the adverse wind which continued to blow with considerable violence the whole day, during which we passed many bergs, much worn away by the long continued action of the waves, and in consequence presenting more variety of figure than any we had before met with in the southern ocean: with the thermometer very little below the freezing point, we greatly enjoyed the high temperature of a milder climate, notwithstanding the occasional showers of snow that fell during the day. At 3 p.m. we again wore, and stood to the S.W., expecting the wind from that quarter, the barometer, at the same time, indicating the approach of fine weather. But still the westerly swell prevented our making any considerable progress, and the whole of the next four days was spent struggling with but small effect against the strong westerly and south-westerly wind that prevailed, taking advantage of every slight change of wind to attain our object, and occasionally getting sight of the main pack when we stretched to the southward of the 64th degree of latitude.
At noon the 14th, we were lat. 62° 42′, long. March 14.156° 51′ E. The mercury in the barometer at that time had attained the unusual height, for these latitudes, of 29.5 inches, at which it stood steadily until midnight, (the wind then shifting to the north, accompanied by a very thick fog,) when it again fell, as rapidly as it had risen, until at noon March 15.the following day it had reached 28.8 inches. We had so often before this time experienced such sudden oscillations of the barometer, that we were in consequence prepared to expect the sudden and violent squall which, however, came on so furiously as hardly to afford us sufficient time to close reef our top-sails, and furl all the other sails. It was of only four or five hours' duration, and had the good effect of driving off the fog. We had for several days seen only a very few bergs; a circumstance that surprised us greatly, as great numbers were met with in these parts by the American expedition during the preceding summer. They must have either been destroyed by the violence of the winter storms, or drifted away to the northward without their places having been supplied by others from the southern lands. It was a comfortable circumstance for us, and rendered the service less hazardous and anxious than it otherwise would have been, for had we found them here in any considerable numbers during the long dark nights that now prevailed, with a constant succession of storms and foggy weather, it would have been utterly impracticable to have persevered in the navigation, and have obliged us to relinquish our present object. We made sail as the wind gradually abated; but it had raised a high, short, irregular sea, in which the ships rolled and pitched uneasily: with difficulty we kept their heads in the right direction until 8 p.m., when it fell perfectly calm, and the swell took complete command of them, carrying us away, during the whole night, upon a course directly opposite to that we wished to go.
March 16.At four the next morning we had a light wind from the north-eastward, which gradually freshened to a pleasant breeze, veering to the southward as it increased in strength; once more we had all studding sails set, running to the westward, but not within sight of the pack, although a strong blink to the southward clearly indicated that it was at no great distance in that direction: we passed many straggling pieces of ice, and several bergs, but they were by no means numerous; and at noon were in lat. 64° 14′ S., long. 154° 40′ E. Again, as on the previous evening, we had a calm from eight March 17.o'clock until four the next morning, the breeze following the same course as yesterday, beginning in the north-east, veering to the south-eastward about noon, and declining to a light south-westerly wind at midnight. We sailed through a great quantity of young ice as we closed the pack, and at length it became so thick, where there was much heavy ice amongst it, that we could not get within two or three miles of the pack edge, and owing to the heavy swell, and difficulty of steering amongst the ice in which the ships were involved, they received some very heavy blows, but fortunately without doing any other injury than removing some of the copper: the pack presented much the same appearance as that we had sailed along in our way from Cape North of Victoria Land to Balleny Islands; for although at a distance it seemed to be a compact solid-looking mass, still on closer inspection we could make out that it also was composed of heavy loose pieces, amongst which the undulations of the ocean could be perceived, as far as we could discern from the mast-head; and the rolling motion of the larger pieces clearly showed that the frost had not yet been sufficiently severe to perfectly bind them together into an unbroken field: we continued to run to the westward, as close along the edge of the pack as the strong pancake ice permitted, until dark, when we hauled off into clearer water for the night. The Aurora Australis was seen for about a quarter of an hour, about 11 p.m. bearing west by compass, shooting up bright coruscations to the altitude of forty-five degrees: in some parts it appeared in a diffused light along the edges of the clouds.
March 18.Being calm at noon, when in lat. 63° 51′ S., long. 151° 47′ E., we tried for soundings, but could not reach the ground with six hundred fathoms. The temperature at that depth, 39.2; at 450 fathoms 38.5; at 300 fathoms 37.5; at 150 fathoms, 35.5; at the surface 30.4; and the specific gravity of the water throughout 1.0272 at the temperature of the freezing point. With a moderate breeze from the north-east, we made good way to the westward during the afternoon and evening; and although it became thick with snow towards midnight, we continued our course through the night under moderate sail, and by keeping a vigilant look-out avoided the bergs and heavy ice we were sailing amongst.
As we were now approaching the meridian of the pole indicated by M. Gauss's theory, although in a somewhat lower latitude, such magnetic observations as depended not on the weather were made in uninterrupted succession, and the variation of the compass was observed whenever the sun was to be seen between the clouds which covered the sky nearly the whole day. At noon we were in lat. 64° 20′ S., long. 148° 45′ E., dip 84° 27′ S., var. 15° 45′ E.: standing to the S.W. under all sail, direct for the point we were seeking, we made the heavy pack edge at 8 p.m., and bore away along it to the westward, through streams of young ice and loose pieces from the pack; the sky was overcast, but there was sufficient light from the moon to enable us to run without hazard during the night.
At seven the next morning, when in lat. 65° March 20.15′ S., and long. 144° 53′ E., and therefore only forty-five miles north of the spot, our observations gave a dip of 85° 5′, but the variation could not be observed, owing to the clouded state of the sky, between the evening of the 19th, when in lat. 64° 24′, and long. 148° 27′ E., it amounted to 16° 41′ E., and the evening of the 20th, in lat. 65° 4′, and long. 142° 49′, when it was 12° 37′ E.; the main pack prevented our nearer approach to the interesting point, but our observations perfectly corroborate those we made in the highest southern latitudes, as to the real position of the magnetic pole, although we were here about six hundred miles from it, and will therefore not have been made in vain: they differ, however, more than I expected from those obtained by Lieutenant Wilkes the preceding summer, making due allowance for the difference of our geographical positions; thus, in lat. 67° 4′, long. 147° 30′ E., his observed dip amounted to 87° 30′; whilst ours, in nearly the same meridian, 147° 15′ E., and in latitude 64° 56′, was only 85° 3′, being at least a degree of difference greater than our distance apart would justify. In his letter to me it had been first written 86° 30′, and then altered to 87° 30′, so that I may be mistaken which he meant it to be, especially as 86° 30′ would be a very near accordance with our observations. I have not been able to ascertain the dip observed by the French Expedition at this spot.
One only object now remained for us to accomplish before seeking a milder and more congenial climate: on our voyage between Kerguelen Island and Van Diemen's Land, we had crossed the line of no variation in latitude 46° S., and longitude 134° 30′ E.[1]; it appeared to me desirable to ascertain its situation in as high a latitude as circumstances admitted, and to recross it in our way to Hobart Town in an intermediate latitude, and by thus determining its place at three distinct and nearly equidistant points, the nature of the curve by which1841. it reaches the magnetic pole might be computed. As we found the easterly variation to be diminishing rapidly, we might expect, if favoured by circumstances of wind and weather, to accomplish our purpose without any very considerable expense of time: and as our crews continued to enjoy the same good health they had preserved during the whole of the severe season of antarctic navigation, I felt the less hesitation in prolonging their labours in these latitudes a few days longer for so important a purpose.
A fresh south-easterly breeze favoured our wishes, and we had a good run to the westward before the darkness of night compelled us to reduce our speed as we sailed along the margin of the main pack.
At daylight we again made all sail, but the March 21.wind had shifted to the S.W., so that we could not maintain so high a latitude as we desired; at noon we were in lat. 64° 7′, and long. 140° 22′ E., in which position we could not get soundings with six hundred fathoms of line; the temperature at 600 fathoms was 38.7; at 450 fathoms 38; at 300 fathoms 36.5; at 150 fathoms 34; at the surface 30.8; that of the air 27°. Many large icebergs were passed during the day; penguins, cape pigeons, and the blue petrel were about us in great numbers, and a large shoal of porpoises was seen going to the westward.
Observations of the Dip and Variation, made on board H.M.S. Erebus, between the 18th of March and 6th of April, 1841.
| Date. | Position. | Dip S. | Variation. | Remarks. | |
| Lat. S. | Long. E. | ||||
| °′ | °′ | °′ | °′ | ||
| Mar. 18 | 63.52 | 151.50 | 84.06 | — 20.15 | The sign — denotes easterly and + denotes westerly variation. |
| 19 | 64.16 | 149.15 | 84.20 | — 16.40 | |
| 20 | 64.56 | 147.14 | 85.03 | — | |
| 65.15 | 144.53 | 85.05 | — | ||
| 65.04 | 142.46 | — | — 12.37 | ||
| 21 | 64.26 | 140.46 | 84.55 | — 6.57 | |
| 22 | 63.20 | 139.43 | 84.05 | — 5.58 | |
| 62.42 | 138.20 | 84.00 | — 4.05 | ||
| 23 | 62.20 | 136.26 | 83.45 | — 1.12 | |
| 62.06 | 136.07 | 83.30 | — 0.27 | ||
| Cross line of no variation. | |||||
| 25 | 60.23 | 131.38 | 83.10 | + 8.09 | |
| 26 | 59.10 | 130.00 | 82.36 | + 8.32 | |
| 28 | 57.20 | 127.49 | 81.45 | + 8.47 | |
| 29 | 56.16 | 130.46 | 81.00 | + 5.46 | |
| 30 | 55.10 | 131.30 | 80.20 | + 1.34 | |
| 55.07 | 132.40 | 80.00 | + 1.05 | ||
| Re-cross line of no variation. | |||||
| 31 | 54.05 | 134.30 | 79.30 | — 1.44 | |
| Apr. 1 | 52.56 | 135.24 | 78.50 | — 1.03 | Anomalous observation. |
| 2 | 51.12 | 136.55 | 77.40 | — 4.39 | |
| 5 | 44.52 | 143.38 | 73.20 | — 6.00 | |
| 6 | 44.06 | 145.42 | 71.40 | — 10.06 | |
The above table of Magnetic Observations is inserted here to show how rapidly the easterly variation diminished, until we crossed the line of no variation during the night of the 23d, in latitude 62º 0′ S., and longitude 135° 50′ E.; thence how quickly the westerly variation increased until the 28th, when in lat. 57° 20′ and long. 127° 49′ E., it amounted to 8° 47′ W.; and again, how regularly it diminished until we recrossed the line of no variation in lat. 54° 30′ S., and long. 133° 0′ E.
The Aurora Australis was seen at 2 a.m., a broad March 22.band of yellowish light in the north-east. It was again visible at night from nine till near midnight, bearing from N.W. to E. (magnetic), at an altitude of ten degrees, shooting long narrow streamers of colourless light towards the zenith. In the course of the day we passed several bergs of large size; and in the evening we were fortunate in getting good azimuth by means of Sirius and Procyon, by which we found the variation had decreased to 4° 5′ E.
Pursuing our course to the N.W. with a favouring March 23.breeze, our latitude at noon was 62° 12′, longitude 136° 18′; and late in the evening we crossed the line of no variation in latitude 62° 0′ S., and longitude 135° 50′ E. At 7° 20′ p.m. observed a bright arch of the Aurora Australis, W.N.W. and E.S.E., extending across the zenith, of a yellow colour, its edges tinged with a purple hue: in a quarter of an hour the centre of the arch gradually declined to the N.N.E., and disappeared ten degrees above the horizon: a succession of similar arches formed at an altitude of about ten degrees in the S.S.W., their extreme points being also W.N.W. and E.S.E.; the centre of each arch gradually rose towards the zenith, which several of them passed before they disappeared; but generally they became more faint at the altitude of 45°, no longer preserved a regular form, but broke up into small streamers, and disappeared on reaching an altitude of 70°, the lustre of the larger stars was much dimmed as it passed over them, but they could be distinctly seen through it; some of the smaller stars were totally obscured by the brighter and denser portions of the Aurora; this splendid display was, as usual, followed by a fall of snow, and bright diffused auroral light illumined the edges of the clouds from which the snow fell.
March 24.Still running to the north-west to increase the westerly variation, we were unfortunate in not obtaining observations; throughout the day it blew a strong gale of wind from the eastward, with thick falling snow, so that we could seldom see a distance of half a mile before us, and most providentially we did not meet with any bergs. The barometer fell rapidly, and at 10 p.m. stood at 28.33 inches; the gale at that time had considerably abated, and the wind shifted to the north; the snow had given place to a thin mist, slightly lighted up by the Aurora, which only occasionally peeped through in obscure patches, but afforded us as much light as would the moon at quadrature, and which was to us of great advantage.
March 25.At 4 a.m. two icebergs were seen directly ahead of us, but fortunately we had time to avoid them; three others were seen soon afterwards, when the weather was clearer: being becalmed at noon, in lat. 60° 22′ S., long. 131° 28′ E., we tried for soundings with six hundred fathoms: the temperature as indicated by the thermometer at that depth, 40.5°, nearly one degree higher than the mean temperature of the ocean, may have been occasioned by a sudden jerk in hauling it up; the thermometer was, as usual, compared with the standard before and after the experiment, and found to have a small unvarying correction. At 450 fathoms, the temperature was 39.5°: at 300 fathoms, 38°: at 150 fathoms, 37°: at the surface, 35°: several icebergs were in sight at the time, but none within five or six miles.
The Aurora again afforded us considerable light at night, in the absence of the moon, but did not break through the clouds which obscured the sky, and from which very fine snow was constantly falling until nearly 8 p.m., when it appeared from E.N.E. to N.W. of a yellow colour, forming an arch twenty degrees high, and at times exhibiting vivid flashes of a bright pink colour: it dispersed in a quarter of an hour. We continued to make good progress to the north-west during the two following days. In the evening of the 27th we March 27.witnessed a most brilliant exhibition of Aurora Australis, which I shall here insert in detail from the copious notes made at the time by myself and the officers, only first remarking that the constant but light snow of the morning was turned into small rain by the temperature rising at 11 a.m. to 36°: the rain ceased at 7 p.m., after a calm of two hours, and a breeze from the S.W. that followed partially cleared the sky. "At 7 50 p.m. bright coruscations of the Aurora appeared in the west; the streamers rose from a base at 20° above the horizon to an altitude of 70°. At 8 15 it formed a double arch from W.S.W. to E.N.E. at the horizon, the altitude of their centres in the S.S.E. being 38° and 53°; they continued visible forty-five minutes, descending slowly to the S.S.W. At 9 15 p.m. it again appeared W.N.W. and E.S.E. in concentric arches of diffused light, with apparently a rapid internal motion, like a current passing through and lighting up thin mist. The centres of these concentric arches first became visible in the S.S.W. at an altitude of 30°, rising in succession slowly to the zenith, and thence declining in the N.N.E. to an altitude of 50° at 9 50, when the S.S.W. semi-hemisphere was perfectly clear, and the Aurora was very dimly seen to the N.N.E. At 9 53 a bright diffused light suddenly appeared from behind a dark cloud, and two or three minutes afterwards pink and green colours of considerable intensity were seen amongst it, principally at the edges, and before 10 o'clock bright streamers darted upward from the cloud to the zenith, forming coronæ, and exhibiting bright flashes of all the prismatic colours, green and red being the more frequent and conspicuous: this Aurora had much motion, darting and quivering about the sky in rapid flights, and in every direction. It sank in a few minutes beneath the horizon to the S.S.W., in the contrary direction to the series of successive concentric arches of diffused light before mentioned. Some very thin clouds now covered the E.S.E. portion of the sky, and a deposit of very fine snow followed. Heavier clouds soon after rose in the west (to windward), and although we observed no more vivid exhibitions of the Aurora, it continued faintly visible until midnight. Between 10 and 11 p.m., when the sky was very clear in the S.W. quarter of the hemisphere, only one falling star was detected, although carefully watched for.
It blew a strong breeze from the northward all March 28.day, so as to prevent our making much way to the N.W.; and finding from good observations during the forenoon that we had increased the westerly variation to 8° 47′, I did not consider it necessary to stretch any further to the westward. We therefore wore round at 11 15 a.m. for the purpose of recrossing the line of no variation, and of visiting the spot assigned, in my instructions, to one of the foci of greater magnetic intensity, which I had been prevented doing on our way to Van Diemen's Land from Kerguelen Island. At noon we were in lat. 57° 21′ S., long. 127° 35′ E.: during the day we observed several large flocks of a small dark-coloured petrel, which we took to be the young of the Cape-pigeon proceeding to the northward: by the length of time they took to fly past us, we estimated some of those flocks to be from six to ten miles in length, two or three miles broad, and very densely crowded together, literally darkening the sky during the two or three hours they were passing over and about us. A few stormy petrel were also seen.
At 10 30 p.m. a single flash of forked lightning was seen in the N.N.E., and at the same time an arch of Aurora extended across the zenith from the horizon W.N.W. and E.S.E.; it was then blowing March 29.a strong north-westerly gale. Between midnight and 1 a.m. eleven falling stars were observed in the S.W. quarter, and the Aurora was seen and described in the Log-book by the officer of the watch, Lieutenant Sibbald, as follows: "0 30 to 2 10 a.m. observed bright coruscations of the Aurora, forming a succession of arches bearing from west to south at the horizon, passing gradually over to the N.E., each being visible from four to six minutes. At 3 a.m. observed bright coruscations directly over head in the form of a crescent, and of all the colours of the rainbow, visible four minutes."
The gale lasted throughout the day, with violent squalls; but we made good way under close-reefed topsails and reefed courses. Several large flocks of the dark-coloured petrel were again seen to-day, and some large shoals of porpoises, all going to the northward.
March 30.At 1 30 a.m. we passed two narrow lines of heavy ice, the fragments of the numerous bergs about us, and dangerous to merchant vessels keeping so high as the 56th parallel of latitude at this period of the year, on their way to Van Diemen's Land.
The Aurora Australis was visible throughout the night, but without exhibiting any very striking features, generally appearing in a white, diffused, sometimes arched light.
Soon after noon, when in latitude 55° 9′ S., and longitude 132° 28′ E., we hove to, and tried the temperature of the ocean at various depths, as we knew from our observation of the 25th, that we were getting very near to the line of equal temperature throughout its whole depth, which encircles the globe between the fiftieth and sixtieth degree of south latitude. The temperature at 600 fathoms was 39.8: at 450 fathoms, 39.8: at 300 fathoms, 39.5: at 150 fathoms, 39.: and at the surface 38.5: so that no doubt a few weeks earlier we should have here found the mean temperature to prevail, although at this season of the year it was still a short distance to the northward; but we had no opportunity of determining its place more accurately.
During the 30th and 31st we pursued our course March 30, 31.to the north-eastward, favoured by a moderate north-westerly breeze and fine weather. Between the periods of our observations on the evening of the 30th and evening of the 31st we again crossed the line of no variation, and having been fortunate in getting numerous azimuths, the point where we passed over it may be deduced with great exactness.[2] The Aurora appeared in great brilliancy during the night of the 30th; its various phases are minutely noted in the Log-book, and will be found of great value whenever the reduction of the magnetometrical observations at Van Diemen's Land shall be proceeded with. A few icebergs were seen, but not in sufficient numbers to give us any uneasiness.
Just before midnight of the 31st the wind shifted to the S.W., and we made all sail before it.
ABSTRACT OF THE METEOROLOGICAL JOURNAL KEPT ON BOARD HER MAJESTY'S SHIP EREBUS.—MARCH, 1841.
| Day. | Position at Noon. | Temperature of the Air in Shade. | Mean Temperature of Sea at Surface. |
Temp. at 9 a.m. | ||||
| Lat. S. | Long. E. | Max. | Min. | Mean. | Air. | Dew point. | ||
| ° ′ | ° ′ | ° | ° | ° | ° | ° | ° | |
| 1 | 69.04 | 167.45 | 22 | 19 | 20.2 | 28.8 | 22 | 15 |
| 2 | 68.27 | 167.42 | 27 | 16.5 | 21.9 | 28.5 | 24 | 24* |
| 3 | 67.45 | 167.01 | 15.5 | 11.7 | 13.7 | 28.2 | 14 | 12 |
| 4 | 66.44 | 165.45 | 27 | 16 | 23.6 | 28.8 | 23 | 23* |
| 5 | 65.34 | 167.47 | 27 | 23 | 25.1 | 28.8 | 27 | 18 |
| 6 | 65.51 | 164.45 | 31 | 24.5 | 26.6 | 28.8 | 30 | 25 |
| 7 | 65.29 | 162.10 | 32 | 24 | 26.7 | 28.8 | 29 | 29 |
| 8 | 64.38 | 162.53 | 32.5 | 22.5 | 28.8 | 29.3 | 28 | 24 |
| 9 | 64.20 | 164.15 | 33.5 | 30.5 | 32.1 | 30.9 | 32 | 32* |
| 10 | 64.06 | 163.20 | 31.5 | 28.5 | 29.7 | 30.0 | 31 | 31* |
| 11 | 64.03 | 163.09 | 32.5 | 28 | 30.1 | 30.0 | 31 | 29 |
| 12 | 64.12 | 161.20 | 33 | 25 | 28.8 | 29.4 | 33 | 28 |
| 13 | 63.28 | 159.35 | 32 | 25 | 28.7 | 30.2 | 31 | 31 |
| 14 | 62.42 | 156.31 | 30 | 26.5 | 27.9 | 29.4 | 28 | 25 |
| 15 | 64.01 | 155.57 | 32 | 21 | 26.7 | 29.2 | 32 | 32* |
| 16 | 64.10 | 154.40 | 23 | 20.5 | 21.6 | 28.6 | 24 | 22 |
| 17 | 64.22 | 152.58 | 25 | 21.5 | 23.0 | 28.6 | 24 | 24* |
| 18 | 63.51 | 151.47 | 31.5 | 24 | 28.3 | 30.1 | 29 | 26 |
| 19 | 64.21 | 148.45 | 31.8 | 21 | 27.5 | 30.0 | 31 | 31* |
| 20 | 65.15 | 143.45 | 23 | 17.5 | 20.6 | 28.7 | 20 | 17 |
| 21 | 64.07 | 140.22 | 27.5 | 21.5 | 23.3 | 29.0 | 24 | 20 |
| 22 | 62.58 | 139.18 | 33.5 | 27 | 31.2 | 31.1 | 32 | 27 |
| 23 | 62.12 | 136.18 | 35.5 | 32 | 33.5 | 32.3 | 34 | 34* |
| 24 | 61.11 | 133.52 | 33.5 | 32 | 33.1 | 33.5 | 33 | 33* |
| 25 | 60.22 | 131.28 | 39 | 33 | 34.4 | 34.2 | 36 | 35 |
| 26 | 59.24 | 130.03 | 37.5 | 32 | 34.4 | 34.7 | 36 | 33 |
| 27 | 58.03 | 128.40 | 36 | 32 | 34.4 | 35.5 | 33 | 33* |
| 28 | 57.21 | 127.46 | 39 | 35.5 | 37.2 | 36.3 | 39 | 39 |
| 29 | 56.28 | 129.57 | 39 | 35 | 37.2 | 36.6 | 39 | 35 |
| 30 | 55.09 | 132.28 | 44 | 36.5 | 39.7 | 38.0 | 40 | 38 |
| 31 | 54.04 | 134.51 | 41 | 38 | 39.6 | 38.5 | 41 | 41 |
| 44 | 11.7 | 28.69 | 31.12 | |||||
* Snow or rain falling.
ABSTRACT OF THE METEOROLOGICAL JOURNAL KEPT ON BOARD HER MAJESTY'S SHIP EREBUS.—MARCH, 1841.
| Day. | Barometer (corrected). | Winds. | Weather. | ||||||||
| Max. | Min. | Mean. | Direction. | Force. | |||||||
| Inches. | Inches. | Inches. | |||||||||
| 1 | 28.897 | 28.711 | 28.789 | S.W. by W. | 5 | 5 b.c.v.* | |||||
| 2 | .794 | .560 | .632 | S.W. | 3 | a.m.0 g.p.s. p.m. 4 b.c.g. | |||||
| 3 | .740 | .585 | .666 | Southerly | a.m. 4 p.m. 2 |
2 b.c.q. 0 g.p.s. | |||||
| 4 | .678 | .365 | .476 | East | a.m. 4 p.m. 6 |
0 g.p.s. | |||||
| 5 | .967 | .696 | .873 | S.E. | 4 | a.m. 4 b.c.g.p.s. p.m. 3 b.c.g. | |||||
| 6 | 29.001 | .871 | .957 | East | 1 | 5 b.c.v. | |||||
| 7 | .028 | .754 | .858 | N. Easterly | a.m. 4 p.m. 1 |
0 g.s. 3 b.c.g. | |||||
| 8 | .167 | .912 | 29.055 | N. Westerly | a.m. 3 p.m. 4 |
3 b.c.m. 0 d.s. | |||||
| 9 | 28.880 | .615 | 28.726 | N.W. | a.m. 5 p.m. 3 |
0 m.s. 1 b.c.g. | |||||
| 10 | .698 | .536 | .623 | West | 5 | 0 g.q.p.s. | |||||
| 11 | .807 | .588 | .707 | Westerly | 3 | 2 b.c.g.p.s. | |||||
| 12 | .574 | .492 | .528 | Westerly | 3 | 2 b.c.g.p.s. | |||||
| 13 | 29.211 | .457 | .796 | South | a.m. 7 p.m. 5 |
0 g.q.p.s. | |||||
| 14 | .538 | 29.231 | .441 | S.W. | 4 | 3 b.c.g. | |||||
| 15 | .263 | 28.848 | .989 | S. Westerly | 4 | a.m.0 m.s. p.m. 0 c. | |||||
| 16 | 28.963 | .722 | .844 | S. Easterly | 2 | 0 g. | |||||
| 17 | 29.002 | .739 | .872 | Easterly | 3 | a.m. 0 g.p.s. p.m. 0 g. | |||||
| 18 | .144 | .976 | 29.067 | a.m. S.W. p.m. East |
1 | 1 b.c.g. | |||||
| 19 | .061 | .716 | 28.835 | Easterly | a.m. 3 p.m. 5 |
0 m.s. 0 g.p.s. | |||||
| 20 | .014 | .817 | .905 | S.E. by E. | 5 | 0 g.q. | |||||
| 21 | .264 | 29.030 | 29.164 | S.W. | 3 | 0 g.p.s. | |||||
| 22 | .242 | 28.854 | .068 | Easterly | 3 | a.m. 2 b.c.g. p.m. 1 b.c.g.p.s. | |||||
| 23 | .122 | .953 | .024 | East | 2 | 0 m.p.s. | |||||
| 24 | .085 | .332 | 28.692 | E.N.E. | 5 | 0 p.s. | |||||
| 25 | 28.726 | .430 | .614 | E.N.E. | 2 | 3 b.c.g. | |||||
| 26 | 29.166 | .748 | 29.023 | S.W. | 3 | 2 b.c.g.p.s. | |||||
| 27 | .223 | .819 | .011 | E.N.E. | 3 | a.m. 0 m.p.s. p.m. 2 b.c.q.d. | |||||
| 28 | .242 | .736 | 28.897 | N.N.W. | 6 | 3 b.c.q.d. | |||||
| 29 | .309 | .755 | 29.088 | N.W. | 7 | 4 b.c.g.q. | |||||
| 30 | .683 | 29.313 | .445 | N.W. | 3 | 5 b.c. | |||||
| 31 | .741 | .458 | .640 | N.N.E. | 3 | a.m. 3 b.c.g. p.m. 0 g.m.r. | |||||
| 29.741 | 28.365 | 28.8808 | 3.64 | ||||||||
* For the explanation of these symbols, see Appendix.
April 1.Favoured by a moderate breeze from the southwest, we shaped our course for the focus of maximum total intensity, as indicated by the general course of the isodynamic lines in Colonel Sabine's chart of the southern hemisphere, lying in about lat. 47° S. and long. 140° E., a position which we had not been able to attain during our run from Kerguelen Island to Van Diemen's Land, but which we now had in our power of approaching with greater advantage, by a course directly across the isodynamic oval surrounding it. The last iceberg was seen from the mast-head this morning when in lat. 53° 30′ S.: it was of small size.
The wind increased to a strong breeze, and we had a good run during the night.
April 2.Being nearly calm in the forenoon of the next day the boats were lowered down, and soundings were obtained in one thousand four hundred and forty fathoms: our latitude at the time being 52° 10′ S. and long. 136° 56′ E. The weight employed on this occasion was 336 lbs., and the instant of each hundred fathoms passing off the reel was taken as usual, and is given on the following page, by which the increased friction of the line throughout the descent of the weight may be observed. The observations of the temperature which follow serve to show we had crossed the line of mean temperature since our experiments on the 30th March, and that the influence of the sun's heat was here felt to the depth of 450 fathoms.
TIME BY CHRONOMETER.
| Let go at | 3h | 22m | 19s. | ||||
| 100 | fathoms passed out at | 22 | 57 | occupied | 38s | running out | |
| 200 | –– | 23 | 45 | – | 48 | ||
| 300 | –– | 24 | 54 | – | 69 | ||
| 400 | –– | 26 | 10 | – | 76 | ||
| 500 | –– | 27 | 31 | – | 81 | ||
| 600 | –– | 28 | 55 | – | 84 | ||
| 700 | –– | 30 | 27 | – | 92 | ||
| 800 | –– | 32 | 7 | – | 100 | ||
| 900 | –– | 33 | 48 | – | 101 | ||
| 1000 | –– | 35 | 36 | – | 108 | ||
| 1100 | –– | 37 | 31 | – | 115 | ||
| 1200 | –– | 39 | 29 | – | 118 | ||
| 1300 | –– | 41 | 31 | – | 122 | ||
| 1400 | –– | 43 | 34 | – | 123 | ||
| 1500 | –– | 45 | 40 | – | 126 | ||
| Struck ground in 1540 at | 46 | 48 | – | 68 | |||
| 1540 fathoms passed out in | 24 | 29 | |||||
The boat was kept moored to the bottom some time to ascertain if there was any current, but it was not perceptible. The line was then cut, not being sufficiently strong to draw the weight up again.
In the afternoon the temperature and specific gravity of the sea at various depths was tried. The temperature of the surface at the time being 43°; at 150 fathoms, 42°; at 300 fathoms, 41°; at 450 fathoms, 40°, and at 600 fathoms, 39.8°: the specific gravity being the same throughout the whole depth as at the surface, 1.0274, at 43°. A piece of sea-weed, the first we had seen since leaving the antarctic seas, was passed during the afternoon.
In the evening the breeze freshened to a gale from E.S.E., with thick weather and rain, which obliged us to reduce our sail to close-reefed topsails and reefed foresail.
April 3.The gale continued throughout the whole of the next day, with frequent squalls and a high sea running, so that our magnetic observations were not made under favourable circumstances, which was the more to be regretted, as we were now fast approaching the focus of greatest intensity.
In the evening, at 10 p.m., we were in lat. 47° 41′ S. by an observation of the moon's meridian altitude, and must have passed over the point we were in search of about eight o'clock the next morning. April 4.The gale was still blowing with great force, and the sea was running so high as to wash away one of our quarter boats. Very satisfactory observations of the magnetic force were, however, obtained by means of Mr. Fox's invention, and are published in the Second Part of the "Philosophical Transactions of the Royal Society for 1843." They tend to show a smaller relative amount of magnetic force than had been anticipated, and to prove that the focus of greatest intensity lies very much further to the southward than the spot indicated in my instructions, and probably not far from "Terre Adelie" of M. D'Urville. At noon we were in lat. 46° 34′ S. long. 140° 36′ E., and having now completed all that remained to be done, we steered direct for Van Diemen's Land, which we came in April 6.sight of at 10 30 a.m. of the 6th, and late in the evening entered Storm Bay. The light at the entrance of the Derwent was seen soon after midnight, and at nine the next morning the pilot came on board. The wind was blowing fresh down the river, so that it took us until late in the afternoon to beat up. Soon after noon the Governor's barge was seen standing towards us; and our kind friend, who was the last to leave us on our departure for the south, was the first to greet us with his warm and affectionate congratulations on our return. He was received with three hearty cheers from both ships. The vessels were moored in their former berths off the government gardens, convenient to the Rossbank Observatory, after an absence of five months.
In concluding the narrative of our first season's navigation of the Antarctic Seas, I will only further observe, that, amongst the many events which had occurred to call forth our gratitude to God for his guidance and preservation during the arduous and hazardous operations in which we had been engaged, it was a source of no ordinary gratification to me to reflect that the execution of the service had been unattended by casualty, calamity, or sickness of any kind, and that every individual of both ships had been permitted to return in perfect health and safety to this our southern home.