I design to consider some of the particular incitements to 

 the study of Nature, to treat of the history of the contem- 

 plation of the physical universe, or the gradual development 

 of the idea of the concurrent action of natural forces 

 co-operating in all that presents itself to our observation,- 

 and lastly, to notice the specialities of the several branches 

 of science, of which the mutual connection is indicated in 

 the general view of nature in the present volume. References 

 to authorities, together with details of observation, have been 

 placed at the close of each volume, in the form of Notes. 

 In the few instances in which I have introduced extracts 

 from the works of my friends, they are indicated by marks 

 of quotation ; and I have preferred the practice of giving the 

 identical words, to any paraphrase or abridgment. The deli- 

 cate and often contested questions of discovery and priority, 

 so dangerous to introduce in an uncontroversial work, are 

 rarely touched upon : the occasional references to classical 

 antiquity, and to that liighly favoured transition period 

 marked by the great geographical discoveries of the fifteenth 

 and sixteenth centuries, have had for their principal motive, 

 the wish, which is occasionally felt when dwelling on general 



views of nature, to escape from the more severe and dogma- 



. 



tical restraint of modern opinions, into the free and imagi- 

 native domain of earlier presentiments. 



It has sometimes been regarded as a discouraging consi- 



