Page:Aspects of nature in different lands and different climates; with scientific elucidations (IA b29329668 0002).pdf/342

 &c. 203, 240
 * nolia, Helianthus annuus, Victoria regina, Euryale amazonica,

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