368 VIEWS OF NATUEE. 



difference between the eruption of dry ashes and mud-like inun- 

 dations of tuff and trass, investing fragments of wood, charcoal, 

 and shells. The quantity of ashes recently erupted from Mount 

 Vesuvius, like every phenomenon connected with volcanos 

 and other great and fearful natural phenomena, has been 

 greatly exaggerated in the public papers ; and two Neapolitan 

 chemists, Vicenzo Pepe and Guiseppe di Nobili, even asserted 

 that the cinders were mixed with given proportions of gold and 

 silver, notwithstanding the counter-statements of Monticelli 

 and Covelli. According to my researches the stratum of ashes 

 which fell during the twelve days was only three feet in 

 thickness in the direction of Bosche Tre Case, on the declivity 

 of the cone, where they were mixed with rapilli, while in the 

 plains its greatest thickness did not exceed from 16 to 19 

 inches. Measurements of this kind must not be made at 

 spots where the ashes have been drifted by the wind, like 

 snow or sand, or where they have been accumulated in pulp- 

 like heaps by means of water. The times are passed in which, 

 after the manner of the ancients, nothing was regarded in 

 volcanic phenomena save the marvellous, and when men would 

 believe, like Ctesias, that the ashes from Etna were borne as 

 far as the Indian peninsula. A portion of the Mexican gold 

 and silver veins is certainly found in trachytic porphyry, but 

 in the ashes of Vesuvius which I myself collected, and which 

 were, at my request, examined by that distinguished chemist 

 Heinrich Rose, no trace of either gold or silver was to be 

 discovered. 



However much these results, which perfectly correspond 

 with the more exact observations of Monticelli, may differ from 

 those recently announced, it cannot be denied that the erup- 

 tion of ashes, which continued from the 24th to the 28th of 

 October, is the most memorable that has been recorded, on 

 unquestionable evidence, in reference to Mount Vesuvius, 

 since the death of the elder Pliny. The quantity of ashes 

 erupted on this occasion was probably three times as great 



