Appendix. 401 



On the 3d of August, Captain Senhouse of the St. Vincent effect- 

 ed a landing in the Hind cutter, and hoisted the British flag, calling 

 it Graham Island. The form of the crater was found to be nearly a 

 perfect circle, and complete along its whole circumference except for 

 about 250 yards on its south-eastern side, which were broken and 

 low, not apparently more than 3 ft. high. The height of the highest 

 part was found, upon a rough computation, to be 180 ft.j the whole 

 circuit of the island was from a mile and a quarter to a mile and a 

 third. It bore the general appearane of two longitudinal hills, con- 

 nected by intermediate low land sending up smoke and vapor in 

 abundance. The circular basin, the centre of the island, was full 

 of boiling salt water, of a dingy red color ; and the vapor was very 

 oppressive, causing nausea and faintness. 



Captain Senhouse informs us that the fragm.ents of rock brought 

 away by the Hind cutter are compact and heavy, and that the whole 

 surface of the island is dense and perfectly hard under the feet. No 

 variety of lava was procured, nor even any jet or streams of lava 

 seen ; and Mr. Osborne, surgeon to His Majesty's ship Ganges, states 

 that the substances of which the island is composed are chiefly ashes, 

 the pulverized remains of coal deprived of its bitumen, iron scoriae, 

 and a kind of ferruginous clay, or oxided earth. The scoriae occur 

 in irregular masses, some compact, dense, and sonorous, others light, 

 friable, and amorphous, with metallic lustre, slightly magnetic, barely 

 moving the loadstone. A piece of limestone was also found thrown 

 up with the other substances, having no marks of combustion. There 

 were, according to the same observer, no traces of lava, no terra puz- 

 zolana, no pumice, nor other stones, usually found on volcanic hills. 



The principal phenomena attendant on the elevation of Graham 

 Island are the form of the ejected mass and its composition ; and 

 more information will be contained in the study of these two features, 

 than in any hypothetical surmises on the mode of ejection, and on the 

 character and nature of the action by which this took place. 



It will at once be observed, in the sketches of the island which 

 accompany this notice, that its appearance differs very much ac- 

 cording to the distance at which it is viewed. In Fig. 1, it is the 

 summit of a volcano, a cone of eruption slightly elevated above the 

 level of the sea ; but, on a nearer approach, its form is found to be 

 that of a circular cra'ter with more or less perpendicular walls (Fig. 

 2.), like most of the craters of elevation surrounding the internal 

 craters of volcanoes, or the islands and insulated formations of sup- 



VoL. XXL— No. 2. 51 



