No. I. — Account of Mount Vesuvius. 205 



suvius in this Journal, No. xiii. p. 13. The beds in the cra- 

 ter are of great size and thickness, from the many causes 

 which combine to produce the reduction of the indurated ma- 

 terial, the general high temperature and its great alternations, 

 the perpetual moisture and the acidified gases, all contributed; 

 but on the sides of the mountain these causes operate with 

 far less force, and the decomposition of the lavas is proportion- 

 ally slower. The time, however, is dependent upon the 

 quantity of felspar in the lava, for if silex predominates it is 

 not reduced in many centuries. The following is a notice of 

 the state of the lavas in 1828. " Lava of 1551. Fossa di 

 Gaetano. Heaths grow, and vines begin to be planted. 1737. 

 Little decomposed ; moss grows. 1760. More decomposed 

 than the last, but unfit for vegetation. 1771. Gray; moss; 

 no heath. 1785 Fossa di Sventurato. Hard and rough. 

 1794. Fossa di Cucazzello. More decomposed, especially the 

 scoria near the crater. Moss and heath, but no trees. 1805. 

 Fossa del Noce. White ; no moss. 1810. Gray and rough, 

 with some moss. 1822 Colour black ; very rough and irre- 

 gular ; no moss. Many of the above lavas are more forward 

 than that of Ischia, which flowed in 1302." * I took some 

 pains to examine a few of the lavas last year, and found that 

 of 1822 still perfectly sterile ; and from its tremendously un- 

 tractable appearance, it will probably long remain so. I have 

 in my possession characteristic specimens of the lavas of 1777 

 and 1819, with the actual lichens. The former has them 

 pretty long, (about three-eighths of an inch) and bushy. The 

 latter exhibits only minute stalks in the crevices of the rock, 

 and thinly scattered. Much more might be added regarding 

 the decomposition of lava; but we must hasten to notice some 

 other productions of the volcano, -f* 



* Daubeny, p. 204, Note. 



f This paper would be still more imperfect than I feel entitled to make 

 it, were I not to notice the dates of the eruptions of the volcano. I shall 

 merely give the years, and prefix an asterisk to the most tremendous. 

 The following list which I have compiled is, I believe, more complete than 

 any hitherto published. * a. d. 79, under Titus, the first recorded. 



* It destroyed Herculaneum and Pompei, which were much injured by an 

 earthquake which preceded it in 63. This interesting subject I shall resume in 

 another paper. 



VOL. IX NO. II. OCTOBER 1828. O 



