vi Unti'oDuctfom 



vancement in science and knowledge of God's 

 works, not to be able to rely implicitly upon 

 the laws of nature as consistent and con- 

 tinuous. 



In putting out these little volumes, it is not 

 to be understood that the subjects treated will 

 be more than touched upon, at the most salient 

 points. To do much more would require 

 volumes of immense size, and life would be too 

 short for me to write or for you to read them. 



Again : these volumes are " familiar talks." 

 The Author wishes to sit down with you so 

 to speak and not hold you at arm's length. 



It will be his aim to use the language of 

 common life and to avoid all technical names 

 so far as possible, or, when they are necessary, 

 to explain their meaning. The object is to 

 reach the thousands of readers who have not 

 and cannot have the advantages of a scientific 

 education, but who can by this means get at 

 least a rudimentary idea of some of the nat- 

 ural laws with which they are coming in con- 

 tact every hour, and through which the inner 

 man has constant communication with the 

 outer world. It may be, too, that many young 

 students will be helped by these plain general 

 views of topics which their text-books will 

 give them in detail. 



A knowledge of the real things in the ob- 

 jective world about us and the laws that gov- 

 ern them in their inter-relations is of practical 



