INTRODUCTION 



-55 Geology. 



* 5 5 1 Physical Geology. 



553 Economic Geology. 



'5535 Building stones. 



'5535 2 Granites. 



*6 Applied Science in general. 



'6 1 Medicine. 



'6 1 1 Anatomy. 



'6117 Motor system. 



61173 Muscles. 



'612 Physiology. 



[See Table A : subdivisions of '5 and '6.] 



When the number of books in any class is great, it may 

 be convenient to arrange them in groups according to some 

 characteristics other than their common subject. Thus : 



Divisions by Form. Books on say General Chemistry, as 

 shown above, would be all marked "54, but these may differ 

 much in the form of treatment of the subject systematic 

 manuals, dictionaries, essays, magazines, etc. If we insert a 

 cipher to show that our new groups are not limited to any 

 of the subdivisions of General Chemistry, we may write : 



5402 Manual of Chemistry. 



5403 Dictionary of Chemistry. 



5404 Essays on Chemistry. 



5405 Magazine of Chemistry. 



5406 Transactions of a Chemical Society. 

 [See Table B : Form divisions.] 



Divisions ~by Place. Books on say Geology, as shown 

 above, would be all marked -55, but these may deal with 

 different localities or with different strata. If we use brackets 

 to indicate this further departure from our original method, 

 we may write : 



' 5 5 ( * 1 5 ) Geology of coal strata. 



'55( 2 343) Geology of the Alps. 



ix 



