Site of the Ancient City of the Aurunci. 247 



These considerations, if they do not persuade you of the 

 truth of my hypothesis, may at least plead my excuse for 

 having ventured to maintain it, even though it be one which 

 seems to have been repudiated by Sir H. Davy, and which a 

 geologist of reputation once, I think, stigmatized, by desig- 

 nating it as smelling of the laboratory. 



With respect to the former ground of discouragement, I 

 have already given my reasons for not regarding it as abso- 

 lutely fatal ; and with respect to the latter, as we all, I hope, 

 in the nineteenth century, are aware, that modern chemistry 

 is not confined within the limits of the apothecary's shop, I 

 consider it the highest testimony in favour of any geological 

 theory, to be able to say of it, that it has been submitted to 

 the severe ordeal of chemical investigation, and has not been 

 found wanting.* 



In conclusion, then, I will remark, that my visits to 

 Naples have afforded me the materials for laying before you, 

 on this and on two former occasions, a sketch of the pheno- 

 mena presented by the three great volcanic systems which 

 exist within the compass of that territory, and thereby, as it 

 so happens, exhibiting a picture of as many different phases 

 or conditions of igneous action, exemplified in the localities 

 which I have successively brought to your notice, namely, in 

 the country immediately round about Vesuvius, at Mount 

 Vultur, and at Rocca Monfina. 



The first of these localities exhibits, no doubt, the most 



* On this subject, however, it behoves me to speak with some diffidence, when 

 I see the contrary maintained by so eminent a chemist as Professor Bischof of 

 Bonn. All I can say is, that the objections he had originally put forth to this 

 hypothesis have been answered, in a manner which, to my mind at least, appeared 

 satisfactory, in Jameson's Journal for April 1839. The Professor, however, 

 having, in his memoir on the Natural History of Volcanoes and Earthquakes, 

 ■published in the very same number of that Journal, reiterated some of these, 

 and added a few other remarks, I will refer to the Appendix for a statement of 

 the grounds on which I conceive my original views to remain still unshaken ; 

 although it may be suggested, that the Professor's remarks referred to must, 

 from their date, have been written before he could have seen my reply to his 

 original memoir. See Appendix. 



