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The publication in 1814 of a voyage commenced in 1801, and of which all the essential parts were concluded within three years, requires some explanation. Shipwreck and a long imprisonment prevented my arrival in England until the latter end of 1810; much had then been done to forward the account, and the charts in particular were nearly prepared for the engraver; but it was desirable that the astronomical observations, upon which so much depended, should undergo a re-calculation, and the lunar distances have the advantage of being compared with the observations made at the same time at Greenwich; and in July 1811, the necessary authority was obtained from the Board of Longitude. A considerable delay hence arose, and it was prolonged by the Greenwich observations being found to differ so much from the calculated places of the sun and moon, given in the Nautical Almanacks of 1801, 2 and 3, as to make considerable alterations in the longitudes of places settled during the voyage; and a reconstruction of all the charts becoming thence indispensable to accuracy, I wished also to employ in it corrections of another kind, which before had been adopted only in some particular instances.

A variety of observations with the compass had shown the magnetic needle to differ from itself sometimes as much as six, and even seven degrees, in or very near the same place, and the differences appeared to be subject to regular laws; but it was so extraordinary in the present advanced state of navigation, that they should not have been before discovered and a mode of preventing or correcting them ascertained, that my deductions, and almost the facts were distrusted; and in the first construction of the charts I had feared to deviate much from the usual practice. Application was now made to the Admiralty for experiments to be tried with the compass on board different ships; and the results in five cases being conformable to one of the three laws before deduced, which alone was susceptible of proof in England, the whole were adopted without reserve, and the variations and bearings taken throughout the voyage underwent a systematic correction. From these causes the reconstruction of the charts could not be commenced before 1813, which, when the extent of them is considered, will explain why the publication did not take place sooner; but it is hoped that the advantage in point of accuracy will amply compensate the delay.

Besides correcting the lunar distances and the variations and bearings, there are some other particulars, both in the account of the voyage and in the Atlas, where the practice of former navigators has not been strictly followed. Latitudes, longitudes, and bearings, so important to the seaman and uninteresting to the general reader, have hitherto been interwoven in the text; they are here commonly separated from it, by which the one will be enabled to find them more readily, and the other perceive at a glance what may be passed. I heard it declared that a man who published a quarto volume without an index ought to be set in the pillory, and being unwilling to incur the full rigour of this sentence, a running title has been affixed to all the pages; on one side is expressed the country or coast, and on the opposite the particular part where the ship is at anchor or which is the immediate subject of examination; this, it is hoped, will answer the main purpose of an index, without swelling the volumes. Longitude is one of the most essential, but at the same time least certain data in hydrography; the man of science therefore requires something more than the general result of observations before giving his unqualified assent to their accuracy, and the progress of knowledge has of late been such, that a commander now wishes to know the foundation upon which he is to rest his confidence and the safety of his ship; to comply with this laudable desire, the particular results of the observations by which the most important points on each coast are fixed in longitude, as also the means used to obtain them, are given at the end of the volume wherein that coast is described., as being there of most easy reference.

The deviations in the Atlas from former practice, or rather the additional marks used, are intended to make the charts contain as full a journal of the voyage as can be conveyed in this form; a chart is the seaman's great, and often sole guide, and if the information in it can be rendered more complete without introducing confusion, the advantage will be admitted by those who are not opposers of all improvement. In closely following a track laid down upon a chart, seamen often run at night, unsuspicious of danger if none be marked; but some parts of that track were run in the night also, and there may consequently be rocks or shoals, as near even as half a mile, which might prove fatal to them; it therefore seems proper that night tracks should be distinguished from those of the day, and they are so in this Atlas, I believe, for the first time. A distinction is made between the situations at noon where the latitude was observed, and those in which none could be obtained; and the positions fixed in longitude by the time keepers are also marked in the track, as are the few points where a latitude was obtained from the moon.

It has appeared to me, that to show the direction and strength of the winds, with the kind of weather we had when running along these coasts, would be an useful addition to the charts; not only as it would enable those who may navigate by them alone to form a judgment of what is to be expected at the same season, but also that it may be seen how far circumstances prevented several parts of the coast being laid down so correctly as others. This has been done by single arrows, wherever they could be marked without confusion; they are more or less feathered, proportionate to the strength of wind intended to be expressed, and the arrows themselves give the direction. Under each is a short or abridged word, denoting the weather; when this weather prevailed in a more than usual degree a line is drawn under the word, and when in an excessive degree there are two lines. Single arrows being thus appropriated to the winds, the tides and currents are shown by double arrows, between which is usually marked the rate per hour.

On the land, the shading of the hills gives a general idea of their elevation, and it has been assisted by saying how far particular hills and capes are visible from a ship's deck in fine weather; this will be useful to a seaman on first making the land, be a better criterion to judge of its height, and those hills not so marked may be more nearly estimated by comparison. Behind different parts of the coast is given a short description of their appearance, which it is conceived will be gratifying to scientific, and useful to professional men. The capes and hills whose positions are fixed by cross bearings taken on shore or from well ascertained points in the track, as also the stations whence bearings were observed with a theodolite, have distinguishing marks; which, with all others not before in common use, are explained on the General Chart, Plate I.

To have laid down no more than the lands and dangers seen in the Investigator and other vessels under my command, would have left several open spaces, and obliged the seaman to have recourse to other charts where the difference of positions might have perplexed; the discoveries and examinations of former navigators which come within the sphere of each sheet, are therefore incorporated with, or added to mine, but so marked as to be distinctly known. In making the combination, alterations in their longitudes were frequently necessary to agreement; and that they might be made with every regard to accuracy, the charts of the former discoveries were compared with the astronomical observations, narratives, or manuscript journals, when such could be had, and the alterations introduced where there seemed to be the best authority. This has been done with the charts of the east coast of New South Wales, published by Mr. Dalrymple from the manuscripts, as it should appear, of captain Cook; and since it may be thought presumptuous in me to have made alterations in any work of so great a master, this case is selected for a more particular explanation.

Time keepers were in their infancy in 1768, when captain Cook sailed upon his first voyage, and he was not then furnished with them; his longitude was therefore regulated only by occasional observations of lunar distances and some few of Jupiter's satellites, which even in the present improved state of instruments and tables, require to be connected by time keepers before satisfactory conclusions can be drawn. Errors of greater or less magnitude were thence unavoidable; at Cape Gloucester, where I quitted the East Coast, my longitude was 20½' greater than captain Cook's chart--at Cape York where the survey was again resumed, it was 58½; and to incorporate the intermediate parts, it was necessary not only to carry his scale of longitude 20½' more west, but also to reduce the extent of the coast. The chart was compared with the narrative and chart in Hawkesworth, and the log book of the Endeavour with them all; when it was found that reductions might be made in various places upon one or more of the above authorities, for differences between them were frequent and sometimes considerable, and in one instance alone a reduction of 12' in the chart was obtained. It is said in Hawkesworth (III, 202), "As soon as we got within side the reef (through Providential Channel) we anchored in nineteen fathom;" and afterwards (p. 204), that the channel, "bore E. N. E. distant ten or twelve miles." In the first chart the distance is 14½ miles, and nearly the same in that which accompanies the narrative; but in the log book it is said to be 2½ miles only, which corresponds with having anchored as soon as they got within the reef, and has been adopted. In some cases it was not easy to make a choice between these different authorities; but I have commonly followed the narrative and log book when they were found to specify with precision, and they generally produced such corrections to the chart as brought the longitudes of places nearer to my positions. Captain Cook's track in Plates XI. XII. and XIII. is laid down afresh from the log book; and many soundings, with some other useful particulars not to be found in the original chart, are introduced, for the benefit of any navigator who may follow the same route.

The reconstruction of the charts in the Atlas was done upon various scales, but that no error might escape unseen, the least was of ten inches to a degree of longitude; they were then reduced by Mr. Thomas Arrowsmith to four inches, this being thought sufficiently large for a general sailing scale; and each reduced sheet was scrupulously compared by me with the original before it went into the engravers hands, and the proof impressions with the drawing until no errors were found. To those who may read this voyage with a view to geographical information, a frequent reference to the Atlas is earnestly recommended; for many particulars are there marked which it would have been tedious to describe, and should any thing appear obscure in the narrative the charts will generally afford an elucidation.

From the general tenour of the explanations here given, it will perhaps be inferred that the perfection of the Atlas has been the principal object of concern; in fact, having no pretension to authorship, the writing of the narrative, though by much the most troublesome part of my labour, was not that upon which any hope of reputation was founded; a polished style was therefore not attempted, but some pains have been taken to render it clearly intelligible. The first quire of my manuscript was submitted to the judgment of a few literary friends, and I hope to have profited by the corrections they had the kindness to make; but finding these to bear more upon redundancies than inaccuracy of expression, I determined to confide in the indulgence of the public, endeavour to improve as the work advanced, and give my friends no further trouble. Matter, rather than manner, was the object of my anxiety; and if the reader shall be satisfied with the selection and arrangement, and not think the information destitute of such interest as might be expected from the subject, the utmost of my hopes will be accomplished.

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N.B. Throughout this narrative the variation has been allowed upon the bearings, and also in the direction of winds, tides, etc.; the whole are therefore to be considered with reference to the true poles of the earth, unless it be otherwise particularly expressed; and perhaps in some few cases of the ship's head when variations are taken, where the expression by compass, or magnetic, may have been omitted.