With a mind at once philosophical and cultivated, he was able to generalise and describe, to unite erudition with good taste, and to treat questions of deepest science with that grace and picturesqueness of style, which renders them popular without detracting from their accuracy. His love for geology amounted to enthusiasm; he was therefore so zealous in propagating his views, that certain jealous minds could not pardon him, and led him to atone for his fault, by a voluntary exile. The apostle of the science, he likewise was its martyr; thus nothing was wanting to his fame. It is the privilege of men of genius to be persecuted. Obliged to yield to the storm, Pilla left Naples, but by his writings he belonged to Italy at large; and the unanimous acclamation which greeted him in the chair formerly occupied by Galileo, conferred on him by the liberality of the Grand Duke of Tuscany, formed at once his triumph and revenge. Besides the works mentioned, we owe to him a Mineralogical Treatise on Rocks;[35] an Introduction to the Study of Mineralogy;[36] and a Geological Itinerary from Naples to Vienna.[37] Thus, by approving the new productions which his activity produced, and which caused him to be better appreciated by the nation which had adopted him, the Tuscans had only to sanction the judgment they had already given of our _savant_, founded on his reputation and works. Footnote 35: Trattato mineralogico delle Roccie, Napoli. Footnote 36: Introduzione allo studio della geologia, Napoli. Footnote 37: Osservazioni Geologiche che si possono fare lungo la strada da Napoli a Vienna.