CLASSTFTCATIOX. 401 



discovery of an object. Even such apparently trivial and 

 arbitrary arrangements as alphabetical or other indices, 

 are really classifications subject to all the principles of 

 the subject. No such arrangement can be of any use 

 unless it involves sonic correlation of circumstances, so 

 that knowing one thing we learn another. If we merely 

 arrange letters in the pigeon-holes of a secretaire we 

 establish a correlation, for all letters in the first hole will 

 be written by persons, for instance, whose names begin 

 with A, and so on. Knowing then the initial letter^of 

 the writer s name we know also the place of the letter, and 

 the labour of search is thus reduced to one twenty-sixth 

 part of what it would be without any arrangement. 



Now the purpose of a mere catalogue is to discover the 

 place in which an object is to be found, but the art of 

 cataloguing involves logical considerations of some interest 

 and importance. We want to establish a correlation be 

 tween the place of an object and some circumstance about 

 the object which shall enable us readily to refer to it ; 

 this circumstance therefore should be that which will 

 most readily dwell in the memory of the searcher. A 

 piece of poetry, for instance, will be best remembered, in 

 all probability, by the first line of the piece, according 

 to the laws of the association of ideas, and the name of 

 the author will be the next most definite circumstance ; 

 a catalogue of poetry should therefore be arranged alpha 

 betically according to the first word of the piece, or the 

 name of the author, or, still better, in both ways. It 

 would be wholly absurd and impossible to arrange poems 

 according to their subjects, so vague and mixed are these 

 found to be when the attempt is made. 



It is a matter of considerable literary importance to 



decide upon the best mode of cataloguing books, so that 



any required book in a library shall be most readily 



found. Books may be classified in a great number of 



VOL. TI. 



