344 Darwinism and Other Essays. 



before this new catalogue can become the index 

 to all the treasures of the library. 1 



Another great undertaking was begun simul- 

 taneously in 1861. The object of an alphabetical 

 catalogue like those above described is " to enable 

 a person to determine really whether any particu- 

 lar work belongs to the library, and, if it does, 

 where it is placed." If you are in search of 

 Lloyd's " Lectures on the Wave-Theory of Light," 

 you will look in the alphabetical catalogue under 

 "LLOYD, Humphrey." Now this alphabetical ar- 

 rangement is the only one practicable in a public 

 library, because it is the only one on which all 

 catalogues can be made to agree, and it is the 

 only one sufficiently simple to be generally under- 

 stood. For the purpose here required, of finding 

 a particular work, an arrangement according to 

 subject-matter would be entirely chimerical. 

 Nothing short of omniscience could- ever be sure 

 of finding a given title amid such a heterogeneous 

 multitude. Every man who can read knows the 

 order of the alphabet, but not one in a thousand 

 can be expected to master all the points that de- 

 termine the arrangement of a catalogue of sub- 

 jects, as, for example, why one of three kindred 



1 About seventeen thousand of these old titles were added during 

 the two years ending in July, 1877. 



