Make an astrolabe, and obtain the latitude of the island, and, by an eclipse of the moon, the longitude also. By means of the Epitome make a chart on Mercator's projection, and find out the distance from any known land.

I found in my book a description of an instrument used by the ancients to ascertain altitudes and to measure angles, called an Astrolabe, which, upon careful study and examination of the cut, I felt confident would serve my purpose admirably. So to work I went, and in this manner. I made first a strong four-legged stool or bench, about three feet in height and four feet long, and two feet wide upon the top. I then took some nice planed pieces of my dark hardwood and made a smooth surface about an inch thick and five feet square. On this, afterwards to be erected on the stool at right angles like an inverted letter T, I drew a circle with a pair of immense dividers that I made for this purpose, taking in all the area possible, which made my circle about fifty-nine inches in diameter, leaving a margin of one inch,—supposing my inches to have been of the right length; and this I determined by the length of the knuckle of my thumb, which I formerly used for quick measurement, and from which standard I constructed the only rule I ever have used on the island. How nearly correct it is I have no means of knowing. This groove I impressed into the wood by repeatedly turning the dividers around the circumference. I then went to work and subdivided this circle into degrees and minutes, which I did by marking the circle once across at any angle passing through the centre mark, and then by another mark crossing this one at exactly right angles, which I determined by means of my dividers—as laid down in Bowditch's Epitome—by the use of them at equal distances from the centre on the line already marked, sweeping them till the two lines crossed beyond the circumference, making a small mark there so as to erect a perpendicular on the base already drawn. This cut my circle at once into quadrants of 90° each, and these were subdivided again in like manner. I made the circle large on purpose, so as to be able to mark it plainly to sections of one minute each, and by its size to avoid any error in any angle, the chances of which were greatly decreased by every inch of diameter. As I constructed it, I had nearly one-half an inch of circumference to mark sixty minutes upon, and as I only subdivided one of the quadrants it did not take me very long, each degree being represented by a space slightly smaller than a half inch, which was a good large scale to work upon. Having finished the marking of my board I nailed it firmly to the stool in an upright position, with the quadrant, that I had carefully subdivided on the marked circumference, pointing with one of its angles to zenith, and the other on a line with the top of the stool. I then procured a nice straight piece of cane some six feet in length and about an inch in diameter, and with a heated rod of iron burned out all the pith between each joint till I had made a nice tube of that length. Just within the aperture at one end I fastened with a little fish glue a large strong hair from the beard of one of my goats. I then fastened, by means of a hole through the centre of my upright disc, this tube or telescope to it on the side that was subdivided into degrees, and about an inch from the face. I fastened this so that it was held firmly in place, and yet could be moved upon its centre by the pressure of my hand on either arm. This tube I then furnished with a small delicate pin on the outside, in an exact line with the stretched hair inside the tube, and pointing to the degrees and minutes on the marked circumference on the disc, which it almost touched. In other words, if I moved one arm of the tube, the needle on the outside would follow the grooved circumference on the disc, and upon being released would mark some given degree or minute. Having gotten this machine all in order and complete, I placed it one day so as to examine the sun near noon, and here is how I obtained my latitude. What I was doing now was not so very difficult. I well knew that there were several ways to determine latitude. I was aware that the difference of a minute or two even in my altitude, as apparently observed, would not disturb my computation more than a mile or so. In fact each minute marked upon the disc practically stood for one mile of latitude, and the mean of several observations would correct even any errors from this cause.

I waited till I knew that it was nearly noon by the appearance of the sun, and then commenced operations. In the first place I aimed my tube at the sun, and to be able to do so without injuring my eye, I would say that I had fitted the orifice of the tube nearest to me with a piece of smoke-colored membrane or backbone of the squid, which is as transparent as glass, and very thin and delicate. Having, by moving the tube with my hand, brought the sun so that it seemed to stand upon the hair in the outer end of the tube, or like a great capital O upon a base line O, I left it carefully in that position for a moment or two, and then applied my eye again, and found, as I supposed, that the sun no longer seemingly rested upon the hair in my tube, but had risen, which forced me to again lower the arm nearest me and elevate the other extremity, and proved to me that it was not yet noon, and that the sun had not yet reached the meridian. This I did many times, till at last the sun seemed for a minute or so to stand still, as sailors say, and I knew that it was at meridian. I took good care not to touch the instrument, but waited quietly till, by glancing through it, I saw in a few moments the disc of the sun, or lower limb as it is termed, begin to drop below the hair in my tube, and I was then positive that it had passed the meridian. Being assured of this, I went carefully to the marked circumference on the upright disc and noted carefully the degree and minute to which the needle in the side of the tube pointed, which in this case was 54° 51'. Having carefully marked this down with ink upon birch bark, I went again to the other end of the tube, and, elevating it, brought the outer end down toward the sea till the hair and the horizon seemed to be one. I then again carefully observed the degree and minute at which the needle pointed, which in this case was 7° 16', and my task was done; for, by subtracting 7° 16' from 54° 51' I obtained 47° 35', which was exactly the apparent altitude of the sun at noon on September 22, 1866, civil account; and, having that, it was easy to determine the latitude in the following manner:—

Thus I demonstrated the latitude of my island; but now for the longitude. To obtain that I knew that I must first ascertain the time at the island: I could do nothing without that; for longitude was, as I well knew, simply time changed into degrees. I thought of fifty different ways to obtain correct time, but believed none of them sufficiently accurate for my purpose. I could make a sundial for one thing, find out the length of the day by the Epitome and Nautical Almanac, make candles to burn such a length of time, sand to run down an inclined plane at such a rate, but none of these would do.

The difference of a minute, or one-sixtieth of a degree, in an observed altitude would only affect, as I have said, my latitude just one mile, whilst an error of time of one minute from true time would, as I was well aware, throw my longitude out just fifteen miles; hence it behoved me to have exact time if I desired to get exact longitude, and therefore I saw nothing for it but that I must construct a clock, and at it I went. It was not such an enormous undertaking after all. Of course I should make it of wood, and in my boyhood I knew many wooden clocks that kept excellent time; besides, if I could only construct something that would keep time for an hour or two without much error, it would answer my purpose. If I had a clock that I could set at noon by my observation, nearly correct, I could correct it perfectly by an afternoon observation, and have for an hour or so true time, even if it did gain or lose a few minutes in twenty-four hours. So to work I set, and soon turned out the few small wheels necessary, and the weight and pendulum for the same. I spent little time upon the non-essentials, but put it together inside my house on the wall, open so that I could get at it, and furnished it with wooden hands and a thin wooden face.

After I had arranged it and found that it would tick, and by observations at noon for a few days been able to regulate the pendulum, I went diving into the Epitome and the Nautical Almanac as to how I should utilize it so as to get my longitude, after all; when one evening, in turning over the Nautical Almanac, which was calculated for 1866, 1867, 1868, and 1869, my eye fell upon the following, and I felt that my task was done:—

Total eclipse of the moon, September 30,1866, invisible at Greenwich, visible in South America, South Pacific Ocean, and parts of Africa, Asia, and Indian Ocean.

FORMULA (CIVIL ACCOUNT).

This was all I needed to verify my longitude past peradventure, and I went to work at once, calculating when the eclipse ought to take place, nearly, with me.

At a rough calculation I knew that my island was situated somewhere between the 110° and 120° of longitude west of Greenwich, that is to say, in the neighborhood of seven hours' difference of time later than Greenwich time. Therefore I knew that if the moon entered the penumbra at Greenwich (although invisible) on the 30d. 5h. 44 min. A.M. that I ought to look for it to occur visibly to my eyes somewhere from one to two o'clock in the afternoon of the same day, or seven hours later. The exact difference in the time between Greenwich and that to be observed on my island, changed into degrees and minutes, would, of course be the true longitude west of Greenwich.

It was with the utmost anxiety that I awaited the coming of the 30th of September, for it all depended upon pleasant weather whether or not I should be able to make my observation. I placed my astrolabe so as to be able to move it quickly in any needed direction, as I intended to use the tube to look at the sun through so as not to blind my eyes. I also prepared my birch bark in the house, and commenced practising myself in counting seconds, for I should have to leave my instrument and go to the house, counting all the time to note the time marked by my clock. I found upon practice that I could not make this work very successfully, and that according to the state of my feelings or excitement I counted long and short minutes. This would not do; I must invent something better; and I finally bethought myself of counting the beatings of my pulse with the finger of one hand upon the wrist of the other, and applying the proportion to the interval between the observed time by my clock.

The morning at last came that I so much desired, and nothing could be more beautiful than the balmy, spring-like day that surrounded me. The sky was cloudless and the sun shone down in splendor through a clear and pure atmosphere. The morning passed slowly away, and it seemed as if the moon and sun would never approach each other; but finally, in the afternoon, the heavens showed me that the eclipse would soon take place, and I made my arrangements to take four observations, as follows: Time when moon entered shadow; time when total phase began; time when total phase ended; time when moon left shadow.

Nothing could have been better than the afternoon I experienced to make these observations, and in less than six hours the whole affair was over, with the following result, I having carefully regulated my clock as near as possible by an observation at noon:—

Which, reduced to time, gives the longitude of the island 119° 11' 15 west of Greenwich.

There, my problem was done and I was for the moment happy. Perhaps some will wonder why I cared to obtain the latitude and longitude of my island at all. Let me explain. My Bowditch's Epitome gave the latitude and longitude of all prominent capes, harbors, headlands, light-houses, etc., in the whole Pacific Ocean. In other words, knowing now the latitude and longitude of my own island, I had only to project a chart on Mercator's projection, pricking off the relative positions of the land on all sides of me, as well as the position of my island, to have a practical and useful chart. Of course I should not be able to draw the coast line or the circumference of any island, but my chart would show just what latitude and longitude Easter Island was in, for instance, and just how far and in exactly what direction my island lay from it. Also, how far I was from the American coast, and the exact distance and course from any of the principal ports such as Lima, Valparaiso, Pisco, etc. How far from New Zealand and the Society Islands, and in what direction from them.

Having marked the exact latitude and longitude of each of these places, which were fully given in the Epitome, on my chart, I could call upon my memory often to fill in the coast lines, and even if I should in the case of the islands, make them even imaginary, there would be no harm done, for the little black star on each would show me where the latitude and longitude met exactly, and I should be furnished with a practical chart as far as sea navigation was concerned, but not one that would be of much account in entering any harbors.

I cannot say that at this time I had any fixed plan of escaping from the island, but I very well knew that nothing in the world would aid me so much in the attempt as to know the position in latitude and longitude that the island occupied, and a chart of the surrounding seas, with its numerous islands and headlands on the main land. It can well be conceived that my first task after determining the position of my island was to turn to the Epitome to ascertain the nearest land to me there marked down, and after diligent search this is what I found:—

"Easter Island Peak," 27° 8' south latitude and 109° 17' west longitude.

"Island," 28° 6' south latitude and 95° 12' west longitude.

"Group of Islands," 31° 3' south latitude and 129° 24' west longitude.

"Massafuera," 33° 45' south latitude and 80° 47' west longitude, which I speedily worked out, by the principles of Mercator's sailing, to be in course and distance from my island, as follows:—

Of these four places only two ever had a name, and I did not know whether Easter Island was inhabited or not, and about Massafuera I was totally ignorant.

Easter Island, I knew, of course, was one of the so-called Society Islands, and was the nearest practical land to which I could escape. But how was I safely to pass over a thousand miles of water? This investigation only proved to me what I had so long feared, namely, that my island was out of the track of all trade, and that it would be a miracle should I be preserved by the arrival of any vessel. I knew now that I must really give up all hope in that direction, and set to work seriously to help myself.

I therefore applied myself with great vigor to my chart which I outlined upon nice goatskin parchment, which I glued together till I had a surface nearly four feet square, upon which I could lay out all the Pacific Ocean on a nice, large scale, by Mercator's projection. I went on with my daily work, and made this matter one for evening amusement, and as I pricked off the latitude and longitude of some well-known place, that I in former years had visited, my heart swelled within me with grief and mortification, and I had often to stop and wipe the tears from my eyes before I could proceed.

Release from my prison seemed farther from me than ever, as I advanced in my task, and although I had a sort of morbid pleasure in my work, and a fascination to linger over it, yet I saw plainly that I was indeed cast away; for what could I do alone in a boat, even supposing that I could build one strong enough to resist one thousand miles of water? Who was to steer when I was asleep? and then supposing I should be able to arrive at Easter Island, what guarantee had I that I should not be murdered at once by the natives?

No, here I was fixed beyond fate upon my own island, where, with the exception of companionship, I had everything that human heart could wish for. But on the other hand, without companionship I lacked everything that is worth living for in this world. I felt that the problem of all problems hereafter to me would be how can I escape to some civilized country in safety? And from what I now knew, it seemed as if it would remain a problem till my bones were left whitening in the Hermitage.

My discovery of the latitude and longitude of the island had brought me no comfort, and I felt much more uneasy now than I did before finishing my task. But as the summer weather came on, I regained to a degree my good spirits, keeping, however, the problem of escape continually working in my mind, for I knew that there must be some way to solve it, especially with the resources that I had gathered around about me.