rises at 45° or even more. If the elevation of the cone in his time were only so much, then, since he states that this was also the elevation of the outer walls or amphitheatre, both must have increased pari passu. This view is of course untenable, and we are forced to believe that Captain Miller only gave a rough guess. His remarks on the vegetation are quite inconsistent with one another, for he says,There is no vegetation of any kind within the amphitheatre, but a few small trees are found on other parts of the island, which, however barren it may have been at one time, is now well wooded." Dr. Daubeny, in his description of Barren Island, though quoting from Lieutenant Colebrooke, gives the elevation of the cone at 4,000 feet, which must, I think, have been due to a clerical error. A somewhat modified reproduction of the original sketch is given. Mr. Scrope, in his work on Volcanos (2nd edition, Lond., 1862), writes regarding Barren Island: "This permanently active volcano is a cone about 4,000 feet high, rising in the centre of a circular cliff range, which entirely surrounds it except at one point where the sea has broken in." Though the authority is not given, it seems probable that this account is derived from Dr. Daubeney's, as the elevation is not given at 4,000 feet in any other work. In 1846 the island appears to have been visited by the Danish corvette Galathea, but the only record of the fact is said to be an inscription on a rock on the island-" GALATHEA, 1846." This we failed to observe. In the Bombay Times for July, 1852, on the authority of Dr. Buist, it is stated that the volcano was then very active, but I have not been able to refer to the original account. The chief points in the accounts subsequent to the above will be found incorporated below (see the table on pp. 20, 21). Dr. Playfair, Von Liebig, and the Andaman Committee agree in estimating the angle of the cone at 40° to 45°, and the elevation at from 975 to 980 feet. From the preceding records we may gather the following. The volcano has probably not been in violent eruption since the years which closed the last and commenced the present century. The lava-flow which stretches from the entrance open to the sea to the base of the cone was probably poured out during this period, and raised the level of the encircling valley some 40 feet above its elevation in 1789, when Blair saw it. He makes no mention of a lava-stream in his time. If it did not exist then, it cannot-as has been supposed by some-have been instrumental in the formation of the entrance. That this fissure was probably due to other causes we shall presently see. From Lieutenant Wales' figure it is apparent that no material change has taken place in the general configuration, and as it has been shown that 1,800 feet cannot have been the true height, and about 920 probably was, no great alteration in the elevation is likely to have taken place. 1 The statement "very active" from the Bombay Times is too vague for reliance. In a violent state of eruption, 32°17' 1,800 Parts remote from the cone of smoke, and frequently 1791 Horsburgh A quantity of very white smoke 1801 Almes close to the crater 1803 Horsburgh Exploded regularly every ten 1832 Dr.J.Adam's References. Firewood could be got with a mile 1843 Capt. Miller A clear full stream of trans 45° parent vapour 1848 Dr. Daubeny Founded on Blair's account ..... 4,000! Quotes previous accounts ..... Times 1857 Dr. Liebig Clouds of white vapour issued 40° 980 104° F. ? ..... G. Poulett Account same as that by Dr. 1862 4,000 Scrope Daubeny Account drawn up by Dr. Is there any published record of this visit? Daubeny on Volcanos, London, 1848, p. 413 "Bombay Times," July, 1852 Volcanos, by G. P. Scrope, Report on Barren Island, The names of authorities whose descriptions are not derived from personal observation are given in italics. General Description of Barren Island.-Seen from any side but the north-west, Barren Island appears as a nearly flat-topped hill with numerous spurs running down into the sea. From some aspects, however, the top of a central cone with a column of smoke rising from it is discernible. As the north-west side opens up to view, it is first realized that the island consists of a circular ridge forming a huge amphitheatre, which is broken down at one side for a distance of perhaps 150 yards to the level of the sea. The view obtainable through this entrance discloses a bare cone which rises from the centre of the island. Except at a sort of shoulder not far from the top, and at two peaks close to the summit, no rocks are seen on this cone, its smooth sides being covered with grey ash and occasional strings of shingle. Towards the top some whitish patches are seen, these are due to the presence of gypsum mixed with the ash. The accompanying illustration, it will be observed, is somewhat diagrammatic in its character, being rather of the nature of a bird'seye view, than a representation taken from an actual point of view. The total diameter of the island is, on the authority of Lieutenant Heathcote, 2,970 yards. The circuit of the island, from the time it took us to row round, I estimated at about six miles. The high encircling ridge is formed of somewhat irregularly deposited layers of lava, ash, and conglomerate, which dip away from the centre. A section of these may be seen on the left hand of the gap or entrance, and others at various points on the sea-face, no two of them corresponding exactly in character. These beds or layers generally dip at angles of 35° to 40°, which inclination appears to be continued steadily under the sea, as bottom, except at one place, has not been found with a line of 150 fathoms at one-quarter of a mile from the shore. This steepness has been unfavourable to the formation of a fringing reef of coral of any magnitude, such as we find surrounding some of the islands of the Andaman and Nicobar groups. The elevation of this outer ridge varies somewhat in places, but it probably nowhere is much in excess of 1,000 feet. Its highest points are towards the south and west. The appearance presented by the inner scarped face of this amphitheatre is very peculiar. In several places cornice lines mark the position of particular beds, but a purplish grey, or in places brownish, ash spreads over the steep slopes, except towards the south-west and west, where there are some trees and shrubby vegetation. To the north, south, and east a few tufts of grass-generally arranged in long vertical lines, the first being a sort of protection to those below it-are the only plants which have managed to establish a footing in the loose ash. The outer slopes facing the sea are for the most part covered with a luxuriant vegetation, in which large forest trees may be discerned. These latter attract considerable numbers of fruiteating pigeons (Carpophaga bicolor). From its composition and character, it is evident that this ring of cliffs is the remnant of the original cone which gradually rises from below the sea. For a long time Barren Island was considered by Von Buch and others of his school as a most favourable example of his elevation theory of craters. Since, however, the island is in reality only formed of volcanic materials elevated above the sea without a trace of any pre-existing rocks, it is evident that its peculiar form gives no support to that now exploded hypothesis. Hot Spring.-Close to the landing-place, there is a hot spring which has been mentioned in several of the accounts of the island. Dr. Playfair found the temperature to exceed 140°,-the limit of his thermometer. Dr. Liebig's thermometer was only graduated up to 104°, but judging from the feel to the hands, he estimated it to be near the boiling-point. The Andaman Committee record it at from 158° to 163°. At the time of our visit the highest temperature of the water where it bubbled out of the rocks, close to high-water mark, was 130° F. We therefore failed to boil some eggs in it which we had brought with us for the purpose. The water is perfectly clear and sweet,' and there was no trace of sulphurous vapours. Strange to say, where, though mingled with the sea, it was still too hot for the hand to be retained in it with comfort, there were a number of brilliantly-coloured fish swimming about. Facing the landing-place is the termination of a flow of lava which extends backwards for about a mile to the base of the cone, round which it laps for perhaps of the circumference. The height or thickness of this flow of lava is about 10 feet at first, gradually rising to about 50 feet where it emerges from the base of the cone. The upper surface is deeply cleft and covered over with blocks of black cellular lava which rest upon one another in confused piles. Sometimes they are poised so insecurely one upon another that it is a matter of no little risk to attempt scrambling over them. Towards the base of the flow the rock from its slower cooling is more compact and less cellular. In places it contains white crystals of a mineral resembling leucite. In others it is a true basalt with numerous crystals of olivine. As pointed out by Dr. Liebig, the older lava seen in the section of the ridge differs from this; it consists of a reddish matrix with crystals of felspar (probably sanidine), olivine, and augite. A somewhat similar rock occurs on Narkondam. On our way to the central cone from the landing-place, we at first endeavoured to avoid the rough surface of the lava-flow by keeping on the slope of the gap; but after a short distance the bushes and unevenness of the ground compelled us to strike down on the lava, when we found, to our astonishment, a sort of path which must have 1 The Andaman Committee do not appear to have realized this fact, as they spent no little time and trouble in excavating a well without finding a trace of water. |