28 CELESTIAL, ATMOSPHERIC, AND 



CHAPTEE III. 



CELESTIAL, ATMOSPHEKIC, AND TEREESTRIAL 

 PHENOMENA. 



Aristotle's descriptions and explanations of these three 

 classes of phenomena are such that it is proposed to treat 

 of them in one and the same chapter. .To treat of them 

 separately would erroneously suggest a division such as he 

 never effected. At the present time, the subject-matter 

 dealt with in this chapter would be properly assigned to the 

 sciences of astronomy, meteorology, physical geography, 

 and geology. Aristotle's Meteorology and his work on 

 the Heavens contain, in fact, much information about the 

 heavenly bodies, rainbows, winds, earthquakes, the sea, 

 periodical changes of land and sea, and other phenomena, 

 but the causes assigned for some of these, and the manner 

 in which they are described, show that he did not appreciate 

 their true nature. Such want of appreciation may be seen 

 from the facts that he considered the Milky Way to be due 

 to causes much the same as those by which he believed 

 comets to be produced, that both depended on the ascent of 

 certain vapours from the Earth, and that earthquakes, 

 lightning, and thunder were due to the same general cause 

 as winds. His descriptions and explanations, often accom- 

 panied by the views of other philosophers, are of historic 

 value, and he records some events, such as, for example, 

 some appearances of comets, changes in the distribution of 

 land and sea, and volcanic eruptions and earthquakes, which 

 are very interesting in themselves. 



Inaccurate though his explanations of phenomena often 

 are, yet he shows a desire to reason out rather than to guess 

 at the causes of such phenomena, and, compared with those 

 of his predecessors, his views are generally founded on much 

 more carefully considered arguments. 



The fundamental principles on which his arguments 

 were based, viz., the formation of terrestrial matter from 

 four elements, the natural motions of which were upwards 



