6 Account of a visit to Barren Island. L Xo. 1, 



been the vent for fluid masses of rock, when such eruptions took 

 place on a larger scale than in more recent times. The smaller cone 

 in the centre of the old crater, corresponding in its size to the dimi- 

 nished forces of volcanic action, is of recent origin, and represents 

 those smaller cones of still active volcanoes which are usually dis- 

 tinguished as cones of eruption from the original cones, also called 

 the cones of elevation. 



We have it on record that about 60 years ago, the crater of the 

 little cone was throwing out showers of red hot stones of several 

 tons weight and enormous volumes of smoke (Captain Blair's account 

 Asiatic Researches 1795), and but for the isolated position of the 

 volcano preventing its more frequent observation, we should doubtless 

 be able to fix the date of the eruption that left the stream of lava 

 behind, which is now filling the valley and its outlet into the sea. 

 Since that time it has entered the period of decline of volcanic 

 activity, without however leaving us the assurance that it will not 

 some day revive again. 



From barometrical observations, I deduced the height of the 

 cone by Gauss's formula, allowing for the time of the day and the 

 influence of the hot ground near the summit, to be about 980 feet, 

 from the level of the sea to the northern edge of the crater. This 

 height is confirmed by a trigonometrical measurement of Lieutenant 

 Heathcote, I. N., to whom I am indebted for the communication 

 of his results. He visited the Island about four months earlier than 

 we did, when he found the height of the cone 975 feet above the 

 level of the sea, and the diameter of the Island 2,970 yards, 1.68 

 miles North and South. 



The few notes I could glean respecting the recent history of the 

 Island, are derived from the Island itself, from the records of the 

 Asiatic Society, and from Horsburgh. We found on a rock in the 

 transverse valley the inscription " Galathea 1846," showing that since 

 then no alteration has taken place. The same conclusion can be extend- 

 ed farther back to the year 1831 or 1832, judging from an account 

 communicated to the Asiatic Society (Asiatic Society's Journal, 

 April 1832) by Dr. J. Adam, whose informant landed in the month 

 of March, and reached the base of the cone. By this explicit account, 

 the descriptions of the Island in " Lyell,"* dated 1843, and in Hum- 

 * Lyell's Principles of Geology. 



