ANNOTATIONS AND ADDITIONS. 243 



ANNOTATIONS AND ADDITIONS. 



( l ) p. 226. "A more complete determination of the 

 height of all parts of the margin of the crater!' 



Oltmanns, my astronomical fellow labourer, of whom, 

 alas ! science has been early deprived, re-calculated the 

 barometric measurements of Vesuvius referred to in the pre- 

 ceding memoir (of the 22d and 25th of November, and of 

 the 1st of December, 1822), and has compared the results 

 with the measurements which have been communicated to 

 me in manuscript by Lord Minto, Yisconti, Monticelli, 

 JBrioschi, and Poulett Scrope. 



A. Eocca del Palo, the highest and northern margin of the Crater 



of Vesuvius. 



Toises. Eng. ft. 



Saussure, barometric measurement computed in 

 1773, probably by Deluc's formula . . . 609 3894 



Poli, 1794, barometic. '. ; V . . . . 606 3875 



Breislak, 1794, barometric (but, like Poll, the for- 

 mula employed uncertain) 613 3920 



Gay-Lussac,LeopoldvonBuch,andHumboldt, 1805, 

 barometric, computed by Laplace's formula, as 

 are also all the barometric results which follow . 603 3856 



Brioschi, 1810, trigonometric . . . . 638 4080 



Visconti, 1816, trigonometric. . . ; . 622 3977 



Lord Minto, 1822, barometric, often repeated . 621 7931 



