Kate Devitt (whose earlier amalgmation of citation and reputation data we noted here) has also posted a ranking of journals by the Google Scholar h-index, but adjusted for volume of publication.  A few things are striking.  Mind and Language, a major journal in its subfield, undoubtedly benefits from the differing citation practices in linguistics, which are more like those in psychology and other social sciences (i.e., lots of citations to other research–other philosophy & social science journals do unusually well, no doubt for the same raeson).  Synthese plunges in this assessment (by comparison to its unadjusted rank, where it was #1 due to sheer volume), but Erkenntnis still does rather well.  History of philosophy journals fare poorly, since historical scholarship does not typically involve extensive citation to other historical scholarship.