ANNOTATIONS AND ADDITIONS. 395 



ANNOTATIONS AND ADDITIONS. 



(*) p. 384. "A more complete determination of the height of all 



parts of the margin of the crater." 



Oltmanns, my astronomical fellow-laborer, of whom, alas ! science 

 has been early deprived, re-calculated the barometric measurements 

 of Vesuvius referred to in the preceding 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 com- 

 municated to me in manuscript by Lord Minto, Yisconti, Monticelli, 

 Brioschi, and Poulett Scrope. 



A. Rocca del Palo, the highest and Northern Margin of the Crater of Vesuvius. 



Toises. Eng. ft. 



Saussure, barometric measurement computed in 1773, pro- 

 bably by Deluc's formula - - - ^ ! 'K *&u - * 609 3894 

 Poli, 1794, barometric - > .^ \ - * * ... 606 3875 

 Breislak, 1794, barometric (but, like Poli, the formula em- 

 ployed uncertain) - . < ,*s V* " 613, 3920 

 Gay-Lassac, Leopold von Buch, and Humboldt, 1805, baro- 

 metric computed by Laplace's formula, as are also all the 

 barometric results which follow ----- 603 , 3856 



Brioschi, 18 10; trigonometric 638 4080 



Visconti, 1816, trigonometric - - - - - - - 622 3977 



Lord Minto, 1822, barometric, often repeated - - - 621 3971 

 Poulett Scrope, 1822, barometric, somewhat uncertain, from 

 the proportion between the diameters of the tube and 



cistern being unknown - - --.-<*"- - 604 3862 



Monticelli and Covelli, 1822 - ~ - - - * -~ - - 624 3990 



Humboldt, 1822 - 629 4022 



Most probable result, 317 toises, or 2027 English feet, above the Hermit- 

 age; or 625 toises, or 3996 English feet, above the level of the sea. 



