372 ERUPTION OF VESUVIUS. 



one hundred francs. Or, calling five francs a dollar, one 

 thousand one hundred and ninety-one, and two thousand 

 eight hundred and twenty dollars ! 



If it took a small fortune to buy these books, it took a 

 large one to make them. The exact amount is not 

 known, but it is estimated at two hundred thousand 

 dollars. The French and Prussian Governments assisted 

 in their publication, but the greater part of the cost was 

 borne by Humboldt himself, and of course was lost. 

 For however successful such works are, scientifically, they 

 are always failures in a mercantile point of view. The 

 labour and expense involved in the writing and publish- 

 ing of these ^v orks gives us a grander idea of Humboldt, 

 .han we could obtain from any relation of his travels. 

 '. ^hey show his intense and unselfish devotion to science, 

 - -a devotion of which few men besides himself were 

 C{ oable, and to which no man ever sacrificed more — and 

 p. .ce him among the literary benefactors of the world. 



But to return to our narrative, from which these biblio- 

 graphical remarks have led us. Humboldt remained at 

 Paris until 1822, when he proceeded to Yerona, where 

 another Congress was being held. There he met the 

 King of Prussia, and after the Congress was over, ac- 

 companied him on a journey through Ital}^, stopping on 

 the way at Venice, Rome, and Naples. While at Naples, 

 Humboldt had several opportunities of visiting Vesuvius, 

 w4iich was in a very active state. A series of eruptions 

 succeeded each other, from the commencement of the 

 year to the time of his visit to Naples, w^hich was in 

 October or November. He made three ascents of Vesu- 

 vius, partly to wdtness the eruption, and repeat his 

 former barometric measurements of the mountain, ana 



