- nolia, Helianthus annuus, Victoria regina, Euryale amazonica,
&c. 203, 240
The different forms of plants determine the character of the landscape
as dependent on vegetation in different zones. Physiognomic
classification or division into groups according to external "facies"
or aspect, entirely different in its principles from the classification
according to the system of natural families. The study of the
physiognomy of plants is based principally on what are called the
vegetative organs, or those on which the preservation of the
individual depends; systematic botany grounds the arrangement
of natural families on a consideration of the reproductive organs,
or those on which the preservation of the species depends 205-210
On the Structure and Mode of Action of Volcanos in the different Parts
of the Earth—p. 211 to p. 241.
Influence of journeys in distant countries on the generalisation of
ideas, and the progress of physical geology. Influence of the
form of the Mediterranean on the earliest ideas respecting volcanic
phenomena. Comparative geology of volcanos. Periodical recurrence
of certain natural changes or revolutions which have their
origin in the interior of the globe. Relative proportion of the
height of volcanos to that of their cones of ashes in Pichincha,
the Peak of Teneriffe, and Vesuvius. Changes in the height of
the summit of volcanos. Measurements of the height of the
margins of the crater of Vesuvius from 1773 to 1822: the author's
measurements comprise the period from 1805 to 1822, 213-228
Particular description of the eruption in the night of 23-24
October, 1822. Falling in of a cone of cinders 426 English feet in
height, which previously stood in the interior of the crater. The
eruption of ashes from the 24th to the 28th of October is the most
