of the horizon. It was necessary that the apparatus of the pendulum should be fixed with solidity; and stones, of the weight of sixty quintals, were fixed in thick walls, with iron chains. Every thing that could be useful was lavished upon me; and, if my observations were bad, I had no excuse; it was entirely my own fault. Unfortunately the health of colonel Mudge, enfeebled by former labours, did not permit him to enjoy with me these preparations, so much as both of us could have wished; but in this respect his place was supplied by one of his sons, captain Richard Mudge, a young officer full of zeal, with whom I completed my labours. The care which I employed in this duty, did not hinder me from stealing an occasional glance at every thing that was fair and good in Scotland, that abode of morality and intelligence. But foreseeing that such objects might cause me to look upon the minute details of weights, lengths, and measures, as somewhat dry, I resolved not to think of them till my return; and, luckily for the experiments, I faithfully kept the word I had pledged to them.

After they were finished, it behoved us to go and repeat them in the Orkneys, the uttermost limit of the English arc. But colonel Mudge, always reflecting upon what might render his operations more complete, perceived, that it was possible to connect the Orkneys with the Shetland Isles, by triangles, whose apices should rest upon the Isles, or rather, upon the intermediate rocks of Faira and Foula. This plan extended the new arc two degrees to the north; and this was sufficient to decide him. But relatively to the general system of the operations of England and France, it had still another advantage of very different importance. This consisted in carrying the English line of operations two degrees towards the east, almost upon the meridian of Formentera, our last southern station in the Mediterranean. By this happy change, the English operation became the prolongation of ours, and the two together form an arc almost equal to the fourth part of the distance from the pole to the equator. If one might hope that the different nations of Europe would agree to choose the basis of a common system of measures, in nature, is there not here an element the most beautiful and the most sure which they could adopt? And this great arc, which, leaving the Balearic Isles, traverses Spain, France, England, and Scotland, and stops at the rocks of the ancient Thule, being taken in combination with the flattening of the earth, which is deduced from the measurement of the pendulum, or from the theory of the moon, will it not give for fundamental unity, or the METRE,' a measure the most complete, and I dare to say it, the most European which can ever be hoped for.

As soon as the possibility of this great project was recognised, it absorbed all our thoughts; the delicate health of colonel Mudge did not permit him to realise it in person, and he entrusted the execution of it to one of the officers who served under his orders. He left me his son, whose assistance had been so useful, and which became still more so. My apparatus, the portable observatory, the

large stones, and the iron chains, were all embarked with the instruments of the English operation, in the Investigator, brig of war, commanded by captain George Thomas, whose activity and skill do not certainly stand in need of any praise of mine, but whose inexhaustible politeness demands all my gratitude. This officer was so good as to take me on board his ship to Aberdeen, where, during a short day, I experienced the most distinguished hospitality. On the 9th of July we set sail for the Shetland Islands. We remained a long time at sea, detained by calms or contrary winds, regretting with all our hearts the loss of so many beautiful nights, which we could have so well employed in making our observations. On the 6th day we left the Orkneys, with their mountains, of a reddish colour, on our left, which even Roman enterprise had not passed; we discovered the Isle of Faira, which saw the vessel of the admiral of the invincible armada broken to pieces upon her rocks. At last the peaks of Shetland appeared to us in their clouds, and on the 18th July, we made the land, not far from the southern point of these Isles, where the tides of the atlantic, clashing with those proceeding from the sea of Norway, cause a continual swell, and an everlasting storm. The desolate aspect of the soil did not bely these approaches to it. It was no longer those fortunate isles of Spain-those smiling countriesValentia, that garden where the orange and lemon trees, in flower, shed their perfumes around the tomb of a Scipio, or over the majestic ruins of the ancient Saguntum. Here, on landing upon rocks mutilated by the waves, the eye sees nothing but a soil wet, desert, and covered with stones and moss, and craggy mountains, scarred by the iclemency of the heavens; not a tree, not a bush, to soften the savage aspect; here and there some scattered huts, whose roofs, covered with grass, allowed the thick smoke with which they are filled to escape into the fog. Reflecting on the sadness of this abode, where we were about to remain in exile during many months, we took a direction, not without trouble, across pathless plains and hills, towards the small assemblage of stone houses, forming the capital called Lerwick. There we began to feel that the social virtues of a country are not to be measured by its appearance of poverty or riches. It is impossible to conceive hospitality more free, more cordial, than that with which we were received. People who, but a moment before were ignorant of our names, were eager to conduct us every where. When informed of the object of our voyage, they gave us of themselves all the information which might be useful; they collected and delivered it to us, with the same interest as if they had been acting in a matter in which they were personally concerned. Above all, we received much essential counsel from Dr. Edmonston, a wellinformed physician, who has published a very good description of the Shetland Islands, and who recollects with pleasure, having attended, when at Paris, the lectures of our colleague M. Dumeril. He gave us a letter to his brother, who resides in the isle of Unst,

the most northerly of the Archipelago; for although, on leaving Scotland, we had thought that we should establish ourselves at Lerwick; and although fort Charlotte, which protects that town, offered for our apparatus a very favourable situation, nevertheless we were attracted by this little isle of Unst, which offered us a station more northerly than Lerwick, by about half a degree, and also a little more easterly, consequently nearer to the meridian of Formentera. It is true, that it did not promise us a very convenient abode; but it may be conceived, that in going, we did not reckon on the enjoyment of luxury; in short, we made the choice which best suited our operations. Our new friends at Lerwick, pointed out to us the most experienced pilot of the isles, and we departed on the evening of the 20th of July, for our final destination. The science of our guide was not useless to us. A thick fog enveloped us; the wind, always favourable, freshened, and our vessel, plunged in profound darkness, flew with the rapidity of an arrow between rocks so numerous, and through straits so narrow, that without being conducted in this labyrinth by management so correct and quick, that it had become, one might almost say, a sense, it must have foundered a thousand times. Arrived at Unst, we eagerly ran over the isle. It presented nothing but fishermen's huts, and here and there some gentlemen's houses, too small to receive the great English instruments. We at first thought of pitching them upon the highest and most northerly mountains of the isle; but the difficulty of transporting thither the great instruments, which must necessarily have been done by men alone, made us give up the project. We preferred a small island called Balta, situated at the entrance of the principal bay of Unst, (which, closing it in, as it were, on the side of the sea, rendered it an excellent harbour, where the brig could cast anchor in perfect safety), and disembarked our instruments. At first I acceded to this choice. But on more nearly examining the new station, and considering how much it was exposed to gusts of wind, the extreme moisture which prevailed, the remoteness from every habitation, and the manifold difficulties which presented themselves to the formation of an establishment sufficiently solid, which the experiments of the pendulum demanded, I dreaded lest, in persisting in it, I should compromise the success of my operations. In consequence of this, captain Mudge and I decided to return to the Isle of Unst, and to ask a reception for ourselves, and our apparatus, in the only house which was in sight. Happily it was that of the brother of Mr. Edmonston, who received us so well at Lerwick. We experienced here the same kindness. A large sheep-fold, which was empty on account of its being summer, and whose thick walls were capable of resisting every storm, received the apparatus of the pendulum. The portable observatory, together with the repeating circle, were established in the garden of Mr. Edmonston. It was not without much labour that we succeeded in landing the large stones, and dragging them to the place of their destination. It required all the efforts of the brig's crew, animated by the obliging perse

verance of the officers. At last, on the 2d of August, we were in a condition to commence our astronomical observations, and on the 10th, we made the first experiment with the pendulum. On the 17th, we had eight of these experiments, and 270 observations of the latitude. I was now certain of the success of the operation; nothing but time and perseverance were required. Unfortunately, captain Mudge began to feel, in a disagreeable way, the influence of this residence. Although he carefully concealed what he felt, and his zeal was in no respect diminished, I myself perceived the alteration of his health, and the winds having brought to our isle a whale ship, which was intended for Spitzbergen, I determined him to avail himself of it to return to a more genial climate. He departed with regret, leaving me, on behalf of his father, all the powers, and even all the assistance of which I could stand in need. It was then, that left alone, I could feel how lucky it was that I had taken up my residence with Mr. Edmonston. The kindness of that excellent man seemed to increase with the difficulty of my situation. When alone, I could not make observations on the repeating circle, the working of which requires two persons, one to follow the star, and the other to mark the indications of the level. Mr. Edmonston, who took as great an interest in my labours as myself, suggested to me the idea of employing, for this latter part of the observation, a young carpenter, who had already given proofs of his intelligence and address in setting up our observatory, and who, besides, like all the peasants of Scotland, and even of these isles, could read, write, and cypher extremely well. I followed this advice; and having rendered the task of my new assistant as simple as possible, I began to give him some lessons a few days before the departure of captain Mudge. He made a very rapid progress, and perhaps acquitted himself better than a more learned assistant; for he observed and marked my level with all the fidelity of a mechanic; and on no account whatever, not even to satisfy my impatience to observe, would he have admitted my results to be good, before they were strictly within the condition which I had prescribed to him; that is to say, before the bubble of the level was in a state of perfect immobility. Nevertheless, as it is very necessary to reserve to on's self some means of verification, when one resolves to make an astronomer of a carpenter, I had, among the numbers which he wrote certain relations which he did not suspect, and which would have shown me his errors, if he had committed them. This happened sometimes at the commencement; and he was always very much surprised at my being able to detect and correct a mistake, which he himself had not perceived when making it, and which I had not seen made. But at the end of three days, there was no occasion for my occult science any longer to display itself. With this useful and sure assistance, I succeeded in the course of two months in collecting 38 series of the pendulum, each of five or six hours, 1400 observations of the latitude in 55 series, made equally on the south and

north of the zenith, and about 1200 observations of the absolute heights of the sun and the stars, to regulate the going of my clock. After this, it may be conceived that I hardly did any thing else than observe, and, in fact, I did not calculate in this place more than three or four observations, at great intervals from each other, in order to assure myself of their general rate, and to guide me in their continuation, delaying the final calculation until my return. In doing so I doubtless acted well, for although I have since devoted much time to them, they are not yet entirely finished. Nevertheless, the agreement of those observations, of which the calculations are completed, shows the accuracy which may be expected of them; and the results which are deduced from them, being combined with those of Formentera of the arc of France, give for the flattening of the earth exactly the same value which is deduced from the theory of the moon, and the measurement of the degrees compared at great distances. This perfect agreement between determinations so different, shows at once the certainty of the result, and the sure method which science employs to obtain it. It will be seen from this notice, that it is not without trouble that this point of precision has been reached, and it will not excite much surprise when it is known, that the variation of the length of the pendulum, by which the flattening is measured, is in all, from the equator to the pole, but four 'millimétres,' that is to say, less than two lines; and from Formentera to Unst, one millimétre and a half, or less than three-fourths of a line. It is these threefourths of a line however, which, appreciated as can now be done, exhibit and measure, even with great accuracy, the flattening of the whole terrestrial spheroid, and prove to us, that in spite of slight accidents of composition and arrangement, which this exterior and slender surface on which we move, presents to us the interior of the mass of our planet is composed of strata perfectly regular, and subjected to the laws of super-position, density, and form, which a primitive state of fluidity had assigned to them. The advantage of having completely performed my operations, how great soever it necessarily appeared to me, was neither the only nor the most precious I experienced in the family which had so kindly received me. If I had remained upon the rocks of Balta, I should, without doubt, have quitted these isles with all the prejudices of a foreigner. I should only have seen the dreariness of their situation, the poverty of their soil, and the inclemency of their sky; I should not have known that they contained beings sensible, kind, virtuous, and enlightened, like those I had the pleasure of knowing;* and even if I could have suspected their existence, which some kind service, some delicate attention would doubtless have disclosed, I should not have experienced the charm

* I cannot here recall all the persons who have loaded me with obligations; I shall add at least to the names of MM. Edmonston's those of Mr. Mowat, of Unst, and Leisk of Lunna.