400. That’s an error.

Google cannot redirect you to http://worldcat.org/search?q=Bibliothèque+l'homme+public+;+ou+analyse+raisonnée+des+principaux+ouvrages+françois+et+étrangers+jean-antoine-nicolas+caritat+marquis+condorcet 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.