Biography of Baron Leopold von Buck. § 



more and more acutely that it is only half observations which 

 I am making. I am perplexed with the contradictions into 

 which Nature seems here to fall with herself, and even my 

 very bodily health suffers under the mortifying feeling of 

 beino- obliged to confess in the end that one does not know 

 what one ought to believe, — frequently does not know if it be 

 even admissible to believe one's very eyes." Again, " I 

 assure you that Nature contradicts herself much more than I 

 here seem to do." (He had been speaking of the neptunic 

 origin of basalt.) " Make the finest and surest observa- 

 tions, and then go a few miles farther on, and you will find 

 occasion, upon grounds just as certain, to maintain the very 

 opposite of your former conclusion. You see that, in such a 

 mess, it is somewhat venturesome to publish observations 

 that are still so imperfectly established. It is possible that 

 they may be altered in a day ; but. two days of Vesuvius 

 would bring all this to a point." These lines afford likewise 

 an interesting proof of the strict scientific conscientiousness 

 of their author. 



Buch arrived for the first time at Naples on the 19th of 

 February 1799 : he studied Vesuvius with the most careful 

 attention, as might have been expected from his longing 

 desire to visit the volcano. He was present again, along 

 with Humboldt and Gay-Lussac, at the eruption of 12th 

 August 1805. To these two visits we are indebted for Buch's 

 excellent and lively descriptions of the phenomena of the vol- 

 cano, and especially for the first attempt to explain the re- 

 lations of these phenomena, — an attempt which has since, 

 after more extensive experience, merely received more exact 

 definitions upon some individual points (nur einzelene nahere 

 Feststellungen erfahren). The whole description is a model 

 of that lively, accurately descriptive, and, at the same time, 

 picturesque and eloquent style by which the writings of the 

 deceased were in general so eminently distinguished. 



In the year 1802 he visited the south of France, the re- 

 markable volcanic district of Auvergne, the great counter- 

 part of our volcanic Eifel. Amongst various other impor- 

 tant matters, he was the first to determine the notion of the 

 rock termed by him trap-porphyry, or (as forming the Puy 

 de Dome) Domite, — a rock to which Hauy afterwards gave 



