INTRODUCTION. 



SPECIAL RESULTS OF OBSERVATION IN THE DOMAIN" 

 OF TELLURIC PHENOMENA. 



Ix a work embracing so wide a field as the Cosmos, which 

 aims at combining perspicuous comjfrehensibility with general 

 clearness, the composition and co-ordination of the whole 

 are perhaps of greater importance than copiousness of detail. 

 This mode of treating the subject becomes the more desirable 

 because, in the Book of Nature, the generalization of views, 

 both in reference to the objectivity of external phenomena 

 and the reflection of the aspects of nature upon the imagination 

 and feelings of man, must be carefully separated from the 

 enumeration of individual results. The first two volumes of 

 the Cosmos were devoted to this kind of generalization, in 

 which the contemplation of the Universe was considered as 

 one great natural whole, while at the same time care was 

 taken to show how, in the most widely remote zones, man- 

 kind had, in the course of ages, gradually striven to discover 

 the mutual actions of natural forces. Although a great accu- 

 mulation of phenomena may tend to demonstrate their causal 

 connection, a General Picture of Nature can only produce 

 fresh and vivid impressions when, bounded by narrow limits, 

 its perspicuity is not sacrificed to an excessive aggregation 

 of crowded facts. 



As in a collection of graphical illustrations of the surface 

 and of the inner structure of the earth's crust, general maps 

 precede those of a special character, it has seemed to me that 

 in a physical description of the Universe it would be most 

 appropriate, and most in accordance with the plan of the 

 present work, if, to the consideration of the entire Universe 

 from general and higher points of view, I were to append in 

 the latter volumes those special results of observation upon 



VOL. v. B 



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