PREFACE. 



The constant progress made in every department of *^^— ^^^ 

 physical science, is a sufficient apology for the prepara- 

 tion and publication of a new elementary text-book on 

 Natural Philosophy. 



The principles of physical science are so intimately 

 connected with the arts and occupations of every-day 

 life, with our very existence and continuance as sentient 

 beings, that public oj)iuion, at J;he present time, impera- 

 tively demands that the course of instruction on this 

 subject should be as full, thorough, and complete 

 opportunity and time will permit. With this view, the 

 author has endeavored to render the work, in all its 

 arrangements and details, eminently practical, and, at 

 the same time, interesting to the student. The illustra- 

 tions and examples have been multiplied to a greater 

 extent than is usual in works of like character, and have 

 been derived, in most cases, from familiar and common 

 objects. 



Great care has been also taken to render the work eom-» 

 plete and accurate, and in full accordance with the latest 

 results of scientific discovery and research. 



In the arrangement of the subjects treated of, and in *^ 

 the incorporation of questions with the text, the most ap- ^ 

 proved methods, it is believed, have been followed. The 



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