Miscellanies. 387 



3. Memoir on the nerves of Fishes. — A subject which had been 

 given out for competition for the highest prize in the Natural Scien- 

 ces, by the French Academy, was an anatomical description of the 

 nerves of fishes. The Academy at its session on the 19th of July, 

 had received but one Memoir. This was written in latin, and accom- 

 panied by the most finished drawings, representing the distribution of 

 nerves in the Perca Lucioperca, the Eson Lucius, and the Petrom- 

 yzon Marinus. The memoir contained many excellent observations, 

 and a history, almost as complete as it was possible to expect of the 

 nerves of the first two species. It was much less perfect in relation 

 to the third, as the writer himself admitted. Nevertheless the Acad- 

 emy, with a view to contribute to the perfection of this work, and to 

 its jDublication, granted, on the principle of encouragement, the en- 

 tire premium of four thousand francs, which had been appropriated 

 to the proposed object. — Rev. Encyc. Juillet, 1830. 



4. On the connection of the Solfaterra loith Vesuvius. — On this 

 point and on the interesting question of the subterranean cavity before 

 the area of the solfaterra, on both of which I have in this paper strong- 

 ly expressed my opinion, I have the satisfaction of being able to cite 

 the authority of Sir Humphry Davy, a philosopher whose sober judg- 

 ment so admirably tempered his ingenious sagacity, as to render even 

 his hypothetical deductions highly valuable. He observes : There is no 

 question but that the ground under the Solfaterra is hollow, and there 

 is scarcely any reason to doubt of a subterranean communication be- 

 tween this crater and that of Vesuvius. Whenever Vesuvius is in an 

 active state, the Solfaterra is comparatively tranquil. I examined the 

 bocca of the Solfaterra, on the 31st February, 1820, two days before 

 the eruption of Vesuvius was at its height. The columns of steam, 

 which usually arise in large quantities when Vesuvius is tranquil, were 

 now scarcely visible, and a piece of paper thrown into the aperture 

 did not rise again, so that there was every reason to suppose the exis- 

 tence of a descending current of air. The subterraneous thunder 

 heard at such great distances, under Vesuvius, is almost a demonstra- 

 tion of the existence of great cavities below filled with aeriform mat- 

 ter, and the same excavations which in the active state of the volcano 

 throw out during; so great a length of time, immense volumes of 

 steam, must, there is every reason to believe, in its quiet state, be- 

 come filled with atmospheric air. — Brewster^s Journal, July, 1830. 



5. Iron Pyrites. — It is known to mineralogists, that common or 

 octohaedral pyrites and the white pyrites, which from their difference 

 of form were considered by Hauy as different ispecies, were found by 



