vi PREFACE. 



manner as that of the human race has spontaneously 

 grown. 



I conceived that a vast amount of knowledge respecting 

 natural phenomena and their interdependence, and even 

 some practical experience of scientific method, could be 

 conveyed, with all the precision of statement, which is what 

 distinguishes science from common information ; and, yet, 

 without overstepping the comprehension of learners who 

 possessed no further share of preliminary educational dis- 

 cipUne, than that which falls to the lot of the boys and girls 

 who pass through an ordinary primary school. And I 

 thought, that, if my plan could be properly carried out, it 

 would not only yield results of value in themselves, but 

 would facilitate the subsequent entrance of the learners into 

 the portals of the special sciences. 



I undertook, therefore, to deliver twelve lectures, not on 

 any particular branch of natural knowledge, but on natural 

 phenomena in general ; and I borrowed the title of " Physio- 

 graphy," which had already been long applied, in a different 

 sense, to a department of mineralogy, for my subject; 

 inasmuch as I wished to draw a clear line of demarcation, 

 both as to matter and method, between it and what is 

 commonly understood by " Physical Geography." 



Many highly valuable compendia of Physical Geography, 

 for the use of scientific students of that subject, are extant ; 

 but, in my judgment, most of the elementary works I have 

 seen, begin at the wrong end, and too often terminate in an 

 omnium gatherum of scraps of all sorts of undigested and 

 unconnected information; thereby entirely destroying the 

 educational value of that study which Kant justly termed 

 the "propaedeutic of natural knowledge." 



