Page:Scientific Memoirs, Vol. 1 (1837).djvu/240

228 From these general conclusions we proceed to a survey of the different kingdoms of nature, in order to submit to a closer examination the peculiarity of their life and their mutual relations. For this purpose we must define more exactly the boundaries of each separate kingdom. Here we must first make a distinction between the celestial and the terrestrial bodies. To the former belong the solar systems, including the earth considered as a planet. The idea of terrestrial bodies comprehends all the different single objects perceptible by the senses in and on the earth. Now, terrestrial bodies, according to their appearing or not appearing as independent organisms, form two principal classes, and this leads to a second division of bodies into the organized and unorganized. We divide the inorganic bodies likewise, as far as we consider them members of the planet, into the constituent parts of the body of the earth, and the constituent parts of the atmosphere, viz. 1. Fossils and liquids; 2. Gases and vapours. The organic bodies are divided into vegetable and animal bodies. We have therefore four kingdoms of nature, and four different departments of natural philosophy belonging to them. The kingdom of the earth (Geology); the kingdom of the air (Atmospherology); the vegetable kingdom (Phytology, Botany); the animal kingdom (Zoology).

The great elementary masses of the earth are formed and governed by many powers, among which we may distinguish those which relate to the individual preservation of the planet, from those which originate in other heavenly bodies. Of the former the most remarkable is Gravitation, which manifests itself as the immediate principle of internal unity, the sensible tendency of all parts of the earth to a common centre, and therefore to an ideal unity, since according to Euclid no point can be represented materially. But another effect presenting itself in the visible relation of the earth to other heavenly bodies, is that which we perceive under the form of Light. These two powers, when united, produce other phænomena; for instance, heat, which results from the opposition between the rays of light and the direction of gravity: wherefore we observe the heat of the earth to be more intense, the more the heated body is found to be in a straight line between the illuminating and the illuminated object, that is, between the centre of the sun and that of the earth. To these also belongs the phænomenon called magnetism, as the effect of the gravitation of the earth, and its position with respect to the other planets, i. e. the direction of its axis. In heat the predominant principle is light; whereas the predominant principle in magnetism is gravitation. To these we find new powers still added, among which the mechanical and the chemical appear to be allied to gravitation and magnetism, (for the laws of mechanics are