Page:Aspects of nature in different lands and different climates; with scientific elucidations (IA b29329668 0002).pdf/253

 E. Plain of the Atrio del Cavallo.

Toises. Eng. ft.

Humboldt, 1822, barometric                        403  —  2577

F. Foot of the cone of ashes.

Toises. Eng. ft.

Gay-Lussac, Leopold von Buch, and Humboldt, 1805, barometric                                370  —  2366

Humboldt, 1822, barometric                        388  —  2481

G. Hermitage del Salvatore.

Toises. Eng. ft.

Gay-Lussac, Leopold von Buch, and Humboldt, 1805, barometric                                300   —  1918

Lord Minto, 1822, barometric                      307.9 —  1969

Humboldt, 1822, barometric repeated               308.7 —  1974

Part of my measurements have been printed in Monticelli's Storia de' fenomeni del Vesuvio, avvenuti negli anni 1821-1823, p. 115; but the neglected correction for the height of the mercury in the cistern has somewhat disfigured the results as there published. When it is remembered that the results given in the above table were obtained with barometers of very different constructions, at various hours of the day, with winds from very different quarters, and on the unequally heated declivity of a volcano, in a locality in which the decrease of atmospheric temperature differs greatly from that which is supposed in our barometric formulæ,—the agreement will be found to be as great as could be expected, and quite satisfactory.

My measurements in 1822, at the time of the Congress of Verona, when I accompanied the late King of Prussia to