202 Physical Notices on the Bay of Naples. 



" Prodromo dclla Mineralogia Vesuviana" (a work which I 

 have not been fortunate enough to see,) it displays, I under- 

 stand, too fully that imperfect knowledge, that separation from 

 the literature of modern Europe and the progress of modern 

 science, too prevalent, alas ! in Italy, — the land of Roman 

 greatness, — the land of the Medici, — and the golden age of Leo 

 the Tenth. 



The reduplications of names to the same mineral, where 

 there is not a well established correspondence of scientific men 

 in different quarters, must perpetually occur, especially in Ve- 

 suvius, where species not hitherto noticed are daily brought to 

 light, and after receiving some high sounding name are found 

 to have been long known in the far northern schools of Great 

 Britain, Germany, and Sweden. * The rage for multiplying 

 species too exceeds all bounds, and the slightest, perhaps for- 

 tuitous distinction is considered a sufficient ground for giving 

 a new appellation to the mineral. Where this chaos of unmean- 

 ing language is to end seems doubtful. As things go on at 

 present, the terminology of the science must become so per- 

 plexed as to intimidate the boldest student. These digressive 

 remarks may perhaps have led to the idea that I am going to 

 attempt the reform of the Vesuvian mineralogy ; but far other 

 is the case. They are rather intended as an apology for being 

 able to do so little where more might have been expected, and 

 infinitely more is yet to be looked for. Brevity I must prin- 

 cipally attempt, and that the little I say may be intelligible 

 and satisfactory to the well informed reader. Although, con- 

 trary to the synthetical method, it will be far best to com- 

 mence with the compound rocks of Vesuvius, and then to des- 

 cend to the simple minerals. 



I. Lava. — This rock is for the most part an intimate com- 

 pound of two simple minerals, augite and felspar, although 

 some other species occasionally occupy a large share of the 

 composition. On the general forms and massive grouping of 

 the Vesuvian lavas I have already made some remarks, but 

 in their minuter characters they do not differ less widely. 

 The lavas are for the most part either compact, cellular, or 

 decomposed. The compact kind is generally porphyritic, 



* See this Journal, No. xiv. p. 32G. 

 3 



