INTRODUCTION 



and not for entertainment. Its compilation has 

 occupied the leisure left to the author by the claims 

 of pubhc duty. The authorities drawn upon are 

 faithfully recorded. The matter-of-fact title, in 

 place of some fanciful label, indicates the author's 

 aim, and the practical object of the work is aided by 

 the table of contents that forms Book I, enabhng 

 the reader to turn to any particular subject that he 

 desires to look up. 



Book I : Table of Contents of the remaining 

 thirty-six Books, the contents of each Book being 

 followed by a hst of the previous writers used as 

 authorities. 



Book II (see Book I init.) : Cosmology, astronomy, 

 meteorology, geography, geology. 



XlT 



