502 Mr. R. Mallet on the 



crater and to the highest point of the island. The statements which 

 have been made as to the relative heights of different points of this island 

 appear to be only derived from guess, and are greatly in error, as I am 

 enabled to show, although I am not in a position to give heights which are 

 rigidly correct, my hypsometric measurements having been made by 

 means of a single aneroid. 



Diagram No. 1. 



The pergola of Padre Ranza's house (marked A, Diagram No. 1) was 

 found to be 211 feet above the sea at St. Yincenzo, and the highest point 

 of the island (marked B) is 2843 feet thus measured. Captain Smyth, 

 however, gives the height as only 2576 feet : this was probably taken 

 by him by the usual nautical methods of triangulation, and if so, may not 

 be more exact than my own rough barometric measurement. The height 

 of the ridge overhanging the crater, marked C, was in like manner found 

 to be 1200 feet. We were enabled to clamber down from this over crags 

 of lava, whose irregular terraces and ledges were capped, more or less 

 deeply, with black volcanic sand, containing immense quantities of crys- 

 tals of augite, down to a point overhanging the landward wall of the 

 crater, and at no great distance from its verge, from whence we witnessed 

 the phenomena of eruption. This point, marked C', I found to be 904 feet 

 above the level of the sea. From this point the great, irregular, and 

 somewhat oval funnel-shaped crater was before us ; and looking seaward 

 the highly irregular walls bounding its edges sloped towards the sea, and 

 were united transversely by the sharp irregular edge or summit of the 

 mass of broken and in great part wholly discontinuous and angular 

 ejected fragments, which form a slope down to the sea, between the oppo- 

 site sides or jaws of the cove or reentrant angle in the coast-line called 

 the Schiarrazza. From the point where we stood this edge (D on Diagram) 

 was estimated by the eye and clinometer at about 300 feet below us ; and 

 the narrower width of the crater thus seen across at its brim I estimated 

 at from 300 to 400 feet. The form of the crater as described by Smyth 

 (' Sicily and its Islands,' p. 255) in 1824 was staled to be circular, and 



