400. That’s an error.

Google cannot redirect you to http://worldcat.org/search?q=Locke's+Essay+human+understanding,+condensed+under+superintendence+A.J.+Valpy.+(Epitome+Engl.+lit.).+Condensed+clergyman+john+locke because the request was invalid.

This might be because the link was created a long time ago. Try your search again on Google. That’s all we know.