INTRODUCTION 



*6 Applied Science in general. 



63 Agriculture. 



631 Soils. 



'6316 Fertilisers. 



63167 Chemical. 



6317 Machines. 



634 Forestry. 



65 Commerce. 



[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 Chemistry 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 

 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 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 : 



'55( IT 5) Geology of coal strata. 



55(2343) Geology of the Alps. 



*55(8) Geology of S. America. 



'55(85) Geology of Peru. 



[See Table C : Place divisions.] 



Divisions by Eelation. A book may deal with two or 

 more subjects, or with a subject in its relation to some other 

 topic. After assigning to the book the number denoting its 



IX 



