A Voyage of Discovery and Research in the Southern and Antarctic Regions/Volume 2/Chapter 1

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Cape Horn


CHAPTER I.


Refitting the Ships.—Fossil Trees of Derwent Valley.—Geological Remarks.—Tassman's Peninsula.—Eagle Hawk Neck.—Tesselated Pavement.—Entrecasteaux Channel.—Timber on the Banks of the Huon.—Advantages of Port Arthur.—Mean Level of the Ocean.—Launceston.—Prepare for Sea.—Deviation of the Compass.


​

VOYAGE


OF


H. M. S. EREBUS AND TERROR


TO THE


ANTARCTIC OCEAN,


1839–43.



CHAPTER I.


The success which had attended our first season's 1841operations in the antarctic seas could not fail to raise our hopes and expectations of more extended discoveries on a second visit to those regions; but, as several months must elapse before the proper period for renewing our labours should arrive, we had abundance of time to repair any damages our ships had sustained, and to make all due preparation for the service we had yet to perform.

Upon examining the vessels, we were much gratified to find the injuries they had received amongst the southern ice were very inconsiderable, and placed so little below the line of flotation of the ships, as to be got at without rendering the operation of heaving them down necessary, and the repairs were well within the reach of our own ​resources. We therefore commenced immediately lightening the ships by entirely clearing them out, landing all the stores and provisions, and securing them in warehouses, which his Excellency Sir John Franklin kindly appropriated to that purpose, and devoted exclusively to our use.

Thus also the survey of all the remaining stores, provisions, and materials of every kind was at the same time the more readily accomplished: and we had the satisfaction to find that no one article of any consequence had suffered from the great differences of climate they had been exposed to since our leaving England. Repairing and caulking the ships, stripping and refitting their rigging, cleaning and painting them inside and out, as well as all other requisite operations, were now proceeded with under the immediate direction of the senior lieutenants, Bird and McMurdo.

The ship's portable observatories were again put up near the Rossbank Observatory, and gave employment to every officer of both ships that could be spared from other duties, in making a careful comparison of all the magnetic and other instruments that had been employed during our southern cruize, with those of the fixed observatory, under the superintendence of Commander Crozier.

The two sets of ship's magnetometers were got into adjustment, and were observed simultaneously with those of the observatory on the term days of the 21st April, 28th May, and 23rd June, on ​the expanded system we had all along pursued, with the assistance of His Excellency and those gentlemen volunteers resident in the colony, who had, on every term day during our absence most zealously devoted themselves to the tedious and laborious work; and I have much satisfaction in availing myself of this opportunity of publicly expressing my thankfulness to those gentlemen who continued to afford their valuable services until the entire series of simultaneous observations with the European and American observatories was completed, and to whom all investigators of magnetic science must feel greatly indebted. The following is a statement of the several occasions on which term-day observations were obtained at the Rossbank Observatory, and the names of the gentlemen who assisted Lieutenant Kay, Mr. Scott, and Mr. Dayman in making them.

1840.
Nov. 27. His Excellency
Sir J. Franklin		 Mr. Gell Mr. Gunn Lt. Bagot, 51st Capt. Moriarty, r.n.
Dec. 23. –⁠– Capt. Stanley
H.M.S. Britomart		 –⁠– Mr. Nairne –⁠–
1841
Jan. 20. –⁠– –⁠– Dr. Bernard –⁠– –⁠–
Feb. 26. –⁠– Mr. Gell Mr. Henslowe –⁠– –⁠–
Mar. 24. –⁠– –⁠– –⁠– –⁠– –⁠–
April 21. –⁠– –⁠– –⁠– –⁠– –⁠–
May 28. –⁠– –⁠– –⁠– –⁠– –⁠–
June 23. –⁠– –⁠– Lt. Bagot, a.d.c Dr. Bernard –⁠–
July 21. –⁠– –⁠– Mr. Nairne –⁠– –⁠–
Aug. 27. –⁠– –⁠– Mr. Henslowe Lieut. Bagot Mr. Nairne.
Sept. 22. –⁠– –⁠– –⁠– –⁠– Capt. Moriarty.
Oct. 20. –⁠– –⁠– –⁠– –⁠– –⁠–
Nov. 26. –⁠– –⁠– –⁠– –⁠– –⁠–
Dec. 22. –⁠– Mr. Nairne. –⁠– –⁠– –⁠–
1842.
Jan. 19. –⁠– –⁠– Mr. Gell. –⁠– Mr. Jeffery.
Feb. 25. –⁠– –⁠– Mr. Leicester Mr. Wright –⁠–


​This plan of observation was discontinued after the term-day of February, and the simultaneous mode changed by new instructions from Professor Lloyd.

The medical officers of the expedition, whose judicious measures had been so successful in preventing even the least appearance of disease in any of our crew, having fortunately no professional calls upon their time, visited the more distant parts of the colony, collecting information, and specimens of the geological character of the country, as well as its other natural productions. Amongst the more interesting of these, and which claims the earliest attention of geologists visiting YanDiemen's Land, is the valley of fossil trees, many of which are beautifully and perfectly opalized, and are found imbedded in porous and scoriaceous basalt, and of which Count Strzelecki remarks, in his admirable physical description of this country,—"Nowhere to my knowledge is the aspect of fossil wood more magnificent than in the Derwent Valley, and nowhere is the original structure of the tree better preserved; while the outside presents a homogeneous and a hard glossy surface, variegated with coloured stripes, like a barked pine; the interior, composed of distinct concentric layers, apparently compact and homogeneous, may be nevertheless separated into longitudinal fibres, which are susceptible of subdivision into almost hair-like filaments."

I had an opportunity of visiting these very ​curious remains of a former forest in company with his Excellency Sir John Franklin, and conducted to the more remarkable spots by Mr. Barker, the proprietor of the estate of Rose Garland, where they were discovered by him, and by whose care they have been in some measure preserved from the destructive hammers of wandering geologists. The most beautiful of them has, however, been much disfigured, and a great portion of it carried away. Mr. Barker was so kind as to offer all that remained of it to me, for the purpose of being sent to the British Museum; but it appeared to me a kind of sacrilege to remove such a relic from the spot to which it belonged, where it could be seen to so much more advantage by geologists, and, as I had sent still more complete specimens from Kerguelen Island, would be but of comparatively little value elsewhere. I declined his liberal offer, and begged of him to take more effectual measures for its preservation, which he promised to do.

Dr. Hooker's account of his examination of the fossil wood of this valley, will be equally interesting to the geologist and the botanist. He says,—"one of the most remarkable circumstances, connected both with the geology and botany of Tasmania, is the occurrence of vast quantities of silicified wood, either exposed on the plains, or imbedded in rocks, both of igneous and aqueous formation. Those of the former, in particular, are the most striking, from their singular beauty, and the very perfect manner in which the structure of ​the woody tissue is retained. Soon after my arrival in the colony, magnificent specimens of a fossil tree were shown me, dug out of a volcanic rock. Some of the masses weighed many pounds, and so perfectly resembled splintered white deal in colour and surface, that to believe them stone, it was necessary to feel how hard and heavy they were. I had afterwards an opportunity of visiting the tree from whence these specimens had been obtained, and collected examples from various parts.

"The general aspect of the fossil is that of the stump of a pine-tree, silicified throughout, about six feet in height, and two feet and a half in diameter at the base. It stands upright, in a cliff of hard black or blue-grey vesicular basalt, by which it was originally enclosed, but which has been quarried away from the exposed portion. The lower part, which, however, shows no appearance of dividing into roots, is cylindrical, the upper much injured and broken into such splinters as I had seen at Hobarton. The circumference (which has been called the bark) is composed of a beautiful rich brown glassy agate: it exhibits only obscure traces of concentric rings, and does not fracture in the direction of these, or of the medullary rays. The rest of the wood is of snowy whiteness, with a grain similar to that of deal. Every successive concentric ring or year's growth, amounting to upwards of a hundred, was well marked, from the narrow pith to the agatized ​circumference; but those placed half way between these extremes, on being removed, fell into a snowy-white powdery mass, called "native pounce" by the colonists, resembles amianthus, but is much more brittle. This disintegration of a particular portion of the trunk was not owing to the action of the weather; but to a want of cohesion between the fibres of which the wood is composed.

"Those concentric rings which immediately surround the disintegrated ones, may, with a little force, be divided into laminæ, composed of parallel rows of fibres, beautifully adapted for examination under the microscope: every such ring being divisible, in the direction of the radius, into plates, each consisting of a single row of fibres, held together by the medullary rays, which cross them at right angles like cross-bars. The individual fibres forming one lamina, are of equal length, and in such close juxta-position, that no interstices appear; yet they are separable with the slightest force; proving that the woody substance of the fibre itself is replaced by silica, and that it is not a mere cast of its hollow axis which is preserved.

"In examining silicified woods of the ordinary structure, or such as resemble either the central portion or circumference of this fossil, it is necessary to have thin slices prepared at considerable expense by a skilful lapidary; the object being to obtain such a slice as will display all the characters of the individual fibres. But here such ​slices are naturally prepared, and in the most perfect manner possible.

"Each fibre tapers at both ends to a blunt point, is irregularly four-angular, and solid throughout, its cavity being filled with transparent silica, and its wood wholly replaced by that substance. The surface is marked with those large circular discs which are characteristic of all the pine tribe, and those of this fossil are arranged as in the living genus, Araucaria. I know no species of that genus, however, in which the fibres composing the wood are nearly so large as here. There is also a great peculiarity in the cellular tissues forming the medullary rays: the cells of which are so much transversely elongated as to be six or seven times as long as broad; and their surfaces present impressions of the discs of the woody fibres between which they are interposed.

"It is not easy to conceive how the silicification of this part of the tree was effected; for the infiltration of a fluid charged with silica between the fibres would have consolidated them all into one mass. Again, if the fluid were confined to the cavities of the fibres, forming only casts of these, spaces answering to the thickness of the walls would be left between every one. A transverse section of the agatized portion shows the walls of the fibres to be of considerable thickness, and to be composed of a transparent silica, which also occupies the interstices; whilst their cavities are full of an opaque mass of the same substance."

The morning we had appointed for our visit to the ​valley proved most unfavourable, and the very heavy rain which fell without ceasing throughout the day, drenching us all thoroughly to the skin, prevented that full investigation which we had desired, and hurried all our operations, so that the erratic blocks or boulders of basalt, of which Strzelecki has given so perfect and animated a description, were only superficially examined by us, but as his account of them is of so much interest both to the geologist and general reader, I prefer inserting it to giving my own. Notwithstanding the unfavourable weather, we all greatly enjoyed our excursion, thanks to the polite attention and true English hospitality of Mr. Barker and his family. Strzelecki proceeds to remark[1], that "not less wonderful, and equally interesting, are the erratic blocks or boulders found in the same valley of the Derwent. The masses are composed of cylindrical, somewhat flattened, columns of basalt, confusedly heaped together, with a detritus of pebbles mixed with spheroidal boulders of greenstone rocks, all lodged against an escarpment situated at the bottom of the valley, and on the right hand of the Derwent.

"This escarpment belongs to the carboniferous strata, and was once connected with another escarpment running across the bed of the river, so as to dam up the present outlet of the waters, and thus to form, in conjunction with the other lines yet existing, the perfect and continuous margin of a basin. The violence with which this embankment ​was burst asunder is obvious, as is also the action of the water upon it. The position of the detritus, and the direction of the axes of the columns, which lie in position corresponding to the present fall of the country, that is, at the lowest level of the valley, prove that the disturbing forces acted from within the basin.

"This is corroborated further by the evidences of the basaltic and trachytic irruption which occurred after the deposition of the variegated sandstones in Van Diemen's Land. That irruption seems to have appeared first about Rose Garland, which is the centre of the valley. The trees there, which had been fossilized, withstood the intensity of the incandescent matter: other trees, placed in circumstances less favourable to their previous fossilization, were consumed; but being either saturated with water, or still green, they resisted in some measure the process of combustion, and have left behind longitudinal moulds in the basaltic scoriæ, with parietal cavities or impressions, similar to the rugged appearance which the carbonization of a tree assumes externally. Into some of these moulds, a second irruptive force appears to have injected fresh lava, thus forming casts of the consumed trees, and records of the succession of volcanic agencies.

"This irruption was followed by that of greenstone in the upper part of the valley; which, accompanied as it was by a sudden upward movement of the bottom, must have precipitated the waters ​from one side of the basin to the other, by which, the barrier, being ruptured at the place where the present escarpment is seen, the drainage of the valley was effected.

"In this movement an area of twelve hundred square miles seems to have been raised to the height of four thousand feet, and the valley to have been overflowed by streams of greenstone and basalt, issuing from five mouths—the present lakes of the so-called upper country of the Derwent."

A large collection of geological specimens was made by Mr. McCormick and transmitted to England; and in the Appendix I have placed his very interesting account of his geological excursions to the more remarkable parts of the colony. With reference to the beautiful fossil tree of Rose Garland, he gives some additional particulars of its locality, and of the curious vertical moulds of trees, of which Mr. Barker pointed out several to us. He says, "the tree is imbedded in vesicular lava in a vertical position, at the extremity of a ridge of the same kind of rock, seventy feet above the river, which is here only twelve feet broad, winding through a wooded ravine about one hundred yards across. The height of the tree above the ground is six feet; its circumference at the base seven feet three inches, and its diameter at the top is fifteen inches."

A short distance further down the ridge is another tree, also beautifully silicified; only the upper portion of it remains, vertically imbedded in a ​chimney-like cavity, in the steep face of the igneous rock; the lower portion having been removed has left its cast in the rock, a foot in diameter, to the extent of seven feet. In the soil beneath I found a fragment of it, having an opaline appearance.

The top of this cliff is about forty feet above the river, which is here somewhat narrower, and the ravine not more than sixty yards wide. About two miles from Rose Garland I saw excavations in a low bank of scoriæ, near a curve in the Derwent, where there is a long low island in the centre of the river, lying parallel with its banks, from which two silicified trees had been removed some years ago: they had all been vertically imbedded.

It seems, therefore, quite evident that they were actually growing when the lava in which they are imbedded overflowed the plain. It is a curious fact connected with this subject that, although large external roots are found on some of those fossilized trees, no branches have ever been discovered; as if it required a certain thickness of trunk to resist the effects of the incandescent matter; and the circumstance of finding these trees in an erect position, would seem to prove that the fossilization occurred at the same time with, and was therefore in some manner produced by, the overwhelming matter; and it would be an interesting fact to ascertain whether the roots of any of these trees are still adherent to them, or whether any movement of the whole mass down the valley, during the process of solidification, has removed ​the trees from the places where they originally grew; similar to the progressive movement of the glaciers of Switzerland down the valleys of the Alps.

Before concluding my remarks on the highly interesting fossil remains of the Derwent valley, I cannot omit to notice those which are found in the indurated clay of Point Puer, at Port Arthur, and at Eaglehawk Neck, which is a narrow, low, sandy isthmus, connecting Forestier's with Tasman's peninsula; both of which places I visited in company with the governor. The severe penal settlement of Port Arthur, to which the doubly-convicted felons are transported from New South Wales and Van Diemen's Land,—the juvenile establishment of Point Puer[2], where between five and six hundred convict boys are taught useful trades,—the isthmus of Eaglehawk Neck, where furious dogs are chained to guard the pass, and prevent the escape of convicts from Port Arthur, the coalmines and sandstone quarry, being all objects of interest to the stranger, were visited by nearly all the officers of the expedition, but are too extensively known to require any description here. I am glad, however, to avail myself of a communication from Dr. Jeanneret, the physician to the establishment at Point Puer, containing some interesting particulars respecting the peninsula of Tasmania, and its fossil remains.

"Tasman's Peninsula is the rugged land at the south-eastern extremity of Van Diemen's Land. It ​is deeply indented with bays and promontories, and contains about 120 square miles of surface, chiefly mountains, varying in elevation from 700 to 3000 feet. It is for the most part thickly wooded with the Eucalyptus globulosa, E. robusta, E. piperita, E. myrtifolia; Acacia decurrens, A. affinis, A. melonoxylon, A. saligna, A. verticillata; Zerea and Alsophila, in the hills and gullies. In many parts, particularly on the coast, are Casuarinæ, Banksiæ, and the Exocarpus cupressiformis; in this respect agreeing with the other parts of the island. There are very few coniferæ, if any, of any magnitude.

"The nature of the soil varies with the neighbouring rocks. The basaltic hills, in those parts which I have visited, are covered, as in the neighbourhood of Hobarton, with a good-bodied clay, chiefly of a red tint, encumbered with masses of basalt, in a more or less forward state of degeneration. The chief ranges are of this description at the summit. In the lower levels sandstone often crops out, having the basalt overlying and subjacent. Indeed, basalt may be said to be the prevalent rock. The peninsula of Point Puer is formed of an indurated clay, containing fossil remains, consisting chiefly of marine shells, gorgoniæ, corals, &c. I have found a vertebra imbedded. I think it is the cervical vertebra belonging to an animal about the size of a sheep. I cannot now find it amongst the specimens. On this rock rests clay, varying in purity from the finest pipe-clay to ochre. In this alluvium are found silicious fossils of two species of shells, similar to those fossilized ​with aluminous earth in the strata of the same kind at Eagle Hawk Neck; particularly the butterfly shell, as it is called, upon the spot. The siliceous fossils of this genus are almost all imperfect, but do not bear marks of attrition: the contained animals are as completely fossilized as the shells. Their structure, which is curious, may perhaps be as fully demonstrated from these as by living specimens. The shell of the butterfly appears to be a trivalve, the third valve of which is rarely found attached. It is a kind of stalk, by means of which the animal seems to have been fixed to the rocks. The butterfly shell is not so plentifully distributed in the indurated clay rock at Point Puer as it is at Eagle Hawk Neck. The siliceous petrifactions abound in specimens of agate, chalcedony, cornelian, semiopal, and milky quartz; and in druses containing crystals of quartz, chiefly pellucid and amethystine. Pieces of granite, basalt, hornstone, siliceous and fossilized wood, &c., are found in the rock; but these are not so plentiful, nor, generally speaking, of so large a size as at Eagle Hawk Neck; the rock is also softer, being less impregnated with siliceous admixture. It is a breccia, consisting of an impalpable aluminous deposit, which, during its precipitation, has involved substances of various kinds, and remains terrestrial and marine. It contains numerous holes, such as would be formed by the entombment and subsequent decomposition of vegetable and animal forms. I once thought I could trace out the bed of a hawksbill turtle; and roots reduced to carbonaceous and fossilized states ​are not uncommon. The rock is, as usual, traversed by veins of oxide of iron, and in some parts quantities of soft pyrites are found. A well, sunk to the depth of seventy feet in the rock, affords a chalybeate water of unusual strength, an analysis of which I hope to present on a future occasion.

"The slate clay in this locality may be compared to a riband in a sea of basalt; but it is also found varying, nevertheless, as it respects degree of induration, and the quantity and nature of its fossilized contents, in various parts of the peninsula. At Eagle Hawk Neck, as I before mentioned, it is replete with fossils of indurated clay: these are generally coated with oxide of iron. The basis of the rock at this locality bears the semblance of wacke. The extreme regularity of the disposition of the veins of oxide of iron has obtained for it here the designation of the "Tesselated Pavement[3]," forming, at the verge of the shore, planes of rectangular and rhomboidal stones, similar to the well-paved roadway of a town. In many parts of the peninsula the rocks of each description, basaltic, silicious, and aluminous, are partially covered by a bed of sand, mostly of no great depth, forming the Tea-tree Scrubs (Leptospermum). The only specimen from the coal mines at Slopen Main, is a piece of anthracite, containing vegetable impressions."[4]

​As soon after the first term-day observations 1841. were completed, as other duties admitted, I availed myself of the liberal offer of Mr. Blackett to place his yacht, the "Albatross," at my service, to enable me to extend the magnetical observations some distance along the coast, to visit, and determine the position of, the south-west cape—a desideratum of great importance—and to make a survey of the great bank on which we had struck soundings at a distance of nearly one hundred miles from the coast, and which, from the nature of the ground, I believe likely to prove a valuable fishery to the colony. Both the latter purposes were frustrated by a continuance of unfavourable weather, and from finding the rigging of the vessel to be so slight, and so much weakened by long disuse, as to unfit her for contending against the rough weather that at this season of the year prevails along the southern shore of the island. Commander Crozier accompanied me on this excursion, which we were unable to extend beyond Recherche Bay, owing to the loss of our top-mast and straining the head of the main-mast.

The examination of the numerous fine harbours in the Channel of Entrecasteaux occupied us several days, but their full description is unsuited to a place in this narrative. It may be sufficient here to state that the channel affords excellent anchorage in all parts of it, and the access to it has been rendered perfectly safe and easy by the beautiful light-house which has recently been erected on ​the eastern cape of the inlet, called Bruni Head, which from its elevated position may be seen at a great distance, and is a sure mark by which the Actæon Reef may be avoided. There is no other danger after passing Muscle Bay: in the channel the soundings are regular, and the shores bold, as far as the entrance of the Huon river; from this point a mud bank lies off the west shore of the channel, but its limits are well defined by buoys, placed at small distances apart; these are to be left on the port hand in running up to the Derwent. Recherche Bay is not a commodious harbour for ships drawing more than seventeen feet water, and is too exposed for purposes of general refitment. Muscle Bay and Esperance Bay are better adapted for that purpose, when it may not be necessary to procure materials or assistance from Hobarton. From the hill where Mount Royal signal station once stood, the pilot informed me that the Pedro Blanco, or Eddystone rock, could be seen over part of Bruni Island, distant about thirty miles; the weather was too unfavourable when we were off this point, or we would have ascended the hill, to get angles for the survey. The shores of the inlet are extremely beautiful—their picturesque and broken outline, and the luxuriance of the vegetation, whose dingy green colour we had now become so accustomed to, as almost to have forgotten the rich and varied verdure of our own forests, impressed the mind with feelings of regret that so charming a country should remain a useless ​desolate wilderness, although capable of producing an abundance of food for a large population, whilst so many thousands in England have hardly sufficient to subsist on from day to day, and whose labour here would soon raise them to independence and comfort, in a land whose scenery and climate are equal to the more healthy and admired parts of our own country . But the scenery of the Huon is of a still richer character—its banks are clothed with the loftiest and most valuable timber of the colony. Some of the trees we measured were a hundred and eighty feet high, and twenty-eight in circumference, and cover the ground with so dense a forest, that it requires great labour to clear it for agricultural purposes; but when once accomplished, the same rich soil, which produces such fine timber, fully repays the settler by the abundance it afterwards yields under moderately good management. One of the trees pointed out to us rather exceeded two hundred feet in height, and was thirty-eight feet in circumference about three feet from the ground. Along each shore of the inlet and river, at every two or three miles, we observed a small wooden hut or two, and a small sloop building near them; quantities of firewood, the refuse of the trees that had been cut down for the timbers and planking of the vessel, were piled in heaps ready to be shipped oif to supply firewood to Hobarton. The gratification we should otherwise have felt in contemplating the useful purposes to which these hitherto unproductive forests were ​being applied, was quite lost in the reflection that the people themselves were of the most immoral and profligate character, and generally either runaway convicts or fugitives from society, on account of crimes they had committed, and by this kind of labour earned a sufficiency to gratify their habits of drunkenness and debauchery. Whilst lying at anchor off the mouth of the Huon, in the middle of a rather dark night, we narrowly escaped being run down by a vessel coming up the channel before a strong southerly wind; they had no one on deck except the man at the helm, but, by the vigilance of a dog, which was evidently on the look-out, and which barked most violently, directly he saw us the man altered the course of the vessel, just in time to avoid a serious collision, which we had no means of averting.

In the great cove on the right hand, about five or six miles from the entrance of Entrecasteaux Channel, there is very good anchorage at its head. You may go close in to the sandy beach, from whence a road leads up to the light-house on Bruni Head, an object of no small interest in this country, and one, as I have before remarked, of considerable advantage to the commerce of the capital. Vessels that enter the channel late at night generally anchor under the shelter of Partridge Island, which lies off the south point of the great cove, with the island bearing about N.W., so as to afford protection from the heavy breezes which blow from that quarter. You may anchor in perfect safety in ten fathoms water, on a good holding ground. Between ​Partridge Island and the main, the water is so shallow, as barely to admit the passage of a boat, at low water, so that no swell of any consequence can come into the cove from seaward. The little cove four miles further up is a much snugger anchorage; and Esperance Bay, on the opposite shore, is said to be the best harbour in Van Diemen's Land: but as our time did not admit of our examining it, I am not able to give any opinion on its capabilities except that from the entrance it appeared to be an excellent harbour. Port Arthur, in Tasman's Peninsula, however, possesses many advantages, especially for men-of-war wanting extensive repairs, or having to heave down. The large amount of convict labour, which is always available, and the exclusive use of spacious storehouses, in which the ship's crew may be comfortably accommodated, and where the stores and provisions may be kept in perfect safety during the process, are material conveniences on such occasions: and, added to these, the vigilance of a military guard, so essential, and there carried out to the utmost perfection and severity, in order to prevent the escape of convicts from the doubly penal establishment, is equally efficacious in preventing the straggling of the crew into the town, where, being exposed to the temptation of all kinds of excesses, they are at Hobarton, as well as at most seaport towns, likely to be robbed by those who are ever waiting to prey upon the incautious and unsuspicious sailor.

​My principal object in visiting Port Arthur was to afford a comparison of our standard barometer with that which had been employed for several years by Mr. Lempriere, the Deputy Assistant Commissary General, in accordance with my instructions, and also to establish a permanent mark at the zero point, or general mean level of the sea as determined by the tidal observations which Mr. Lempriere had conducted with perseverance and exactness for some time: by which means any secular variation in the relative level of the land and sea, which is known to occur on some coasts, might at any future period be detected, and its amount determined. The point chosen for this purpose was the perpendicular cliff of the small islet off Point Puer, which, being near to the tide register, rendered the operation more simple and exact; the governor, whom I had accompanied on an official visit to the settlement, gave directions to afford Mr. Lempriere every assistance of labourers he required, to have the mark cut deeply in the rock in the exact spot which his tidal observations indicated as the mean level of the ocean. The tides in the Derwent were too irregular, being influenced greatly by the prevalence of winds outside and the freshes from the interior, so that we could not ascertain with the required degree of exactness the point of mean level. It would have been desirable to have fixed a similar mark on some part of the opposite side of the island, but a prolonged series of preliminary ​observations of the tides are necessary, and as these had not been obtained, and our limited stay, as well as the full employment for all our observers, which the necessary experiments with the magnetometers provided, did not admit of our doing it, I can only hope that some individual with like zeal for science with Mr. Lempriere, and with time at his disposal, may yet accomplish this desideratum. I may here observe, that it is not essential that the mark be made exactly at the mean level of the ocean, indeed it is more desirable that it should be rather above the reach of the highest tide: it is, however, important that it be made on some part of a solid cliff, not liable to rapid disintegration, and the exact distance above the mean level (which may also be marked more slightly) recorded on a plate of copper, well protected from the weather, by placing a flat stone with cement between, upon the plane surface or platform which should constitute the mark from which the level of mean tide should be measured.[5]

The most desirable position for such another mark would be near the north-west extremity of the island, and in the vicinity of Cape Grim, near which the Van Diemen's Land Company has a small establishment.

The fixing of solid and well secured marks for the purpose of showing the mean level of the ocean at a given epoch, was suggested by Baron von Humboldt, in a letter to Lord Minto, subsequent to the sailing ​of the expedition, and of which I did not receive any account until our return from the antarctic seas, which is the reason of my not having established a similar mark on the rocks of Kerguelen Island, or some part of the shores of Victoria Land. Upon this subject that great philosopher observes, that "if similar measures had been taken in Cook and Bougainville's earliest voyages, we should now be in possession of the necessary data for determining whether secular variation in the relative level of land and sea is a general or merely a local phenomenon, and whether any law is discoverable in the direction of the points which rise or sink simultaneously."

By the kindness of Sir John Franklin, I was also enabled to extend my magnetic observations for determining the lines of equal variation, dip, and intensity across the island to Launceston, and thence down an arm of the sea called the Tamar to George Town, where I received a kind welcome, and every assistance, from Lieutenant Friend of the royal navy, the port officer. Launceston, the northern capital of the island, as it has been sometimes called, is very inferior as a town to Hobarton, but the country about it is far more beautiful and valuable. Many of the wealthiest of the colonists have settled in its neighbourhood, but they do not seem to possess any large amount of public spirit, so far as regards the improvement of their favourite city, arising chiefly, I believe, from the expectation that the colonial government would ​and ought to do all that is desirable without their assistance. Vessels of large size come up the river, as it is called, to the town of Launceston; but, unaided by steam, the navigation is rather intricate. George Town, at the entrance of the inlet, is a pretty little village, promising, at some future period, to become a watering place for the fashionables of Launceston; the access to the port is rendered somewhat dangerous and difficult by the bar across its entrance.

During this journey across the country I had an opportunity of witnessing some extensive improvements of which William Kermode, Esq., of Mona Yale, has set the example, by the introduction of a system of draining and irrigation, in which the fertilising effect of water is brought so prominently into observation. Strzelecki has given a very interesting account of these operations, and has pronounced a well-merited eulogium on the perseverance and public spirit of the enterprising proprietor.

We diverged from our direct route, also, as we returned, in order to pass through some of the richest land in the colony, and from which, owing to the agricultural skill and industry of Mr. Archer, and a few other proprietors, the most astonishing crops are produced. In traversing this part of the country in particular, it was impossible not to be struck with the truth of the general remark of all writers, that the diversity of hill and dale, forest and tillage, forming together with the rich and ​beautiful plains traversed by streams, and the comfortable mansions, surrounded by pleasure grounds, of the wealthier settlers, the perfection of agricultural landscape, recall to the recollection scenes so similar in our own country, that imagination could easily find a counterpart to many of the richest scenes of rural beauty which our most admired counties possess. Indeed, after being a short time in this charming country, it is difficult to feel that we are at the farthest distant point of the earth from our own loved land; and wherever we went, the hearty welcome and liberal hospitality with which we were received, seemed to strengthen, in no small degree, the impression of resemblance to our own happy island, except that in this the necessities of travellers being so much greater, offers a proportionally wider field for the exercise of these generous sentiments and conduct.

Towards the end of June we had finished all the repairs and refitment of the ships; had embarked provisions and stores to last us for three years, and were busily employed preparing the vessels for sea, intending, before the season for making another attempt to penetrate to the southward, to visit Sydney, in New South Wales, and the Bay of Islands, in New Zealand, for the purpose of getting magnetometric observations comparative with those of Rossbank Observatory, Van Diemen's Land, as we had done last year at Aukland Island, with the view to ascertain whether the cause of ​perturbation produced exactly similar and synchronous effects on instruments placed at the respective distances of six hundred, and fifteen hundred miles, and which we had only two opportunities last year of observing, at a distance of about a thousand miles from Van Diemen's Land.

The iron tanks, chain cables, anchors, and all iron materials which had necessarily been removed during the repairs of the vessels, having been replaced in the exact spot from which they had been taken, the process of swinging the ship round, to redetermine their united effect upon the compass, was accomplished on the 29th of June. We were surprised to find that both in amount and direction it had very considerably altered. Thus the points of no effect had changed since October, 1840, from nearly N. by W. to nearly N. by E., and from nearly S. by E. to nearly S. by W.; and the amount and direction of extreme deviation from 4º 6′ with the ship's head E. by N. to 5º 30′ with her head E.S.E., and from 4º 16′ with her head W.S.W. to 5º 13′ with her head West.

These results point out in a striking manner the necessity of frequently repeating experiments of this nature, where an ordinary amount of accuracy is desirable; as they moreover serve to prove that some kinds of iron, and perhaps various positions in which it may be placed with reference to the line of dip, render them more susceptible of change than others, or no alteration could have occurred in the direction of the points of minimum and ​maximum effect, and the amount of deviation only would have been affected had the power of the iron in the ship been uniformly increased. Colonel Sabine ascribes this change in the amount of deviation to a different, and perhaps a more probable, cause; and as it is a point of some importance to determine, I will give his explanation in his own words, first remarking, however, that as the greatest care had been taken that the distribution of iron in the ship should be always the same, or as nearly so as possible, the deviation of the plane of no effect amounting to more than a point and a half, cannot have arisen from any slight modifications of this nature, but must be ascribed to some other cause. He observes[6]:—

"After the arrival of the expedition at Hobarton, and before it sailed to the Antarctic Circle, a similar series of observations was made in the Erebus, on the 29th of October, 1840, and again repeated on her return to Hobarton the following autumn, viz. on the 29th of June, 1841. The south end of the needle being now the one which dipped below the horizon (the dip being 70.40 S.), the deviation of the compass was found to take place in the contrary direction to that which had been observed at Gillingham, the disturbance being towards the west as the ship's head went round from north by east to south, and towards the east as her head passed from south through west to north.

​"The line of no deviation was not found to correspond accurately with the north and south points of the compass on either of the occasions at Hobarton; but in 1840 coincided more nearly with the north by west and south by east, and in 1841 with the north by east and south by west. We may perhaps ascribe with probability irregularities of this nature to slight modifications in the distribution of the iron at different periods, which we cannot but view as of not unlikely occurrence; for example, such as might be occasioned by the ship being secured at different times by the starboard or larboard chain cable. In. looking through the observations of the Erebus, it is evident that there was no systematic or constant deviation of the plane of the ship's attraction from that of her principal section; but that the points of no disturbance were sometimes a little on the one side, and sometimes a little on the other, of the north and south points. It appears, therefore, not improper to class these irregularities with those others of accidental occurrence which occasion similar discordances in partial results, and are usually ranged under the general technical head of errors of observation.

"If, further, we compare generally the deviations in 1840 with those of June 1841, the latter appear systematically rather the more considerable in amount. Viewed as a single fact, this circumstance might be regarded simply as indicating that some change had taken place in the interim in the ​arrangement and distribution of the ship's iron, and an easy and natural explanation might appear to be afforded. It is, however, one of several facts which have presented themselves in the course of a careful examination of the observations of the first two years of the expedition, which seem to point to the possibility of a somewhat different cause; viz., that when a ship changes her magnetic latitude, the corresponding change in the magnetism of the ship, or, more strictly, in that portion of it which is derived from induction, follows, but does not always, or altogether, take place instantaneously. It would accord with this supposition, that the disturbance of the compass should be less in the Erebus on her first arrival at Hobarton in 1840, than on her return there in 1841; because in 1840 she had recently passed through the lowest magnetic latitudes, and in 1841 she came immediately from the highest. The observations in 1840 give a less value for α tan θ[7], than those of 1841; and taking the dip at Hobarton as the value of θ, to which the induced magnetism of the ship on both occasions should strictly correspond, we should have a less value for α in 1840 than in 1841; whereas, if with the same dip we take a mean between the disturbances of the compass on the first arrival and on the return, by which we may be conceived to neutralise in a great measure the temporary influences which ​have been supposed, we find the value of α to be almost identical with the result of the former experiments at Gillingham. From this accordance in the value of the constant, in dips which differ so greatly as from 69 N. to 70 S., we should infer the probability first, that the local attraction of the Erebus was due to induced magnetism alone, the influence of any portions of iron, which, in the strict sense of the term, were permanently magnetic, being insensible; and secondly, that no material change affecting the standard compass had taken place in the distribution of the iron. These inferences are by no means inconsistent with the supposition above suggested, that some portions of her iron might be of a quality intermediate between that of perfectly soft iron, which undergoes instantaneous change, and that of iron which acquires permanent magnetism, and that such portions should be liable, in regard to their magnetic condition, to be more or less in arrear of the ship's magnetic position. I abstain from entering further into this question at present, because a fitter opportunity of doing so will be afforded when the whole of the observations of the expedition shall be collected, including those which have to be made at Rio de Janeiro on the return from the high latitudes of the south, and in England, after passing through the low magnetic latitudes of the equatorial region. Should it prove that the induced magnetism of a ship due to any particular dip requires time for its full development, more or ​less, according to the various qualities of her iron, the corrections to be applied may possibly in some ships be considerably complicated thereby; fortunately in the Erebus the difference in the amount of the disturbance on the two occasions, which gave rise to this discussion, is not of any serious consequence; and we may employ, without any material inconvenience, for our present purpose, the mean of the two series as applicable generally between their respective dates, for which interval we especially desire the corrections."

All other arrangements being completed by the evening of the 6th July, we on that day took leave of our numerous friends in the colony; from whom, during the several months we had lived amongst them, we had received an uninterrupted continuance of the greatest possible kindness and hospitality, and for many of whom we must ever entertain the liveliest feelings of gratitude and regard.

  1. ↑ Strzelecki, Physical Description, p. 148.
  2. ↑ For a statistical account of this establishment, see Appendix, No. III.
  3. ↑ For a detailed account of this curious production of nature, see Appendix.
  4. ↑ This communication was accompanied by a complete and valuable set of specimens, now deposited in the British Museum.
  5. ↑ See Cosmos, p. 288. and note, p. 95.
  6. ↑ Phil. Trans. R.S. Part II. 1843, p. 152.
  7. ↑ See Phil. Trans. R.S. p. 149.
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