400. That’s an error.

Google cannot redirect you to http://worldcat.org/search?q=*Oeuvres J. J. Rousseau. Tome 1. -21.. - Paris : chez Th. Desoer, libraire, 1822-1825. - 21 v. ; 12 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.