Regarding one online source for the text:

The Internet Wiretap online edition of

           AN ENQUIRY CONCERNING

HUMAN UNDERSTANDING

                    by

DAVID HUME

         Harvard Classics Volume 37

Copyright 1910 P.F. Collier & Son

    Prepared by 

The text in its entirety: http://www.knuten.liu.se/~bjoch509/works/hume/human_underst.txt

About the online edition.

This was scanned from the 1910 edition and mechanically checked against a commercial copy of the text from CDROM.

Differences were corrected against the paper edition. The text itself is thus a highly accurate rendition. The footnotes were entered manually.

This text is in the PUBLIC DOMAIN, released August 1993.