U. S. District Court Judge Julius J. Hoffman, who once called Bobby G. Seale, national chairman of the Black Panther Party, "a dangerous man," dropped riot conspiracy charges against him Monday.

Seale and seven others-the "Chicago Eight"-stood trial last fall and winter on conspiracy charges stemming from disturbances at the 1968 Democratic National Convention. Seale was severed from the case by Hoffman for his behavior in the courtroom and given a four-year contempt of court sentence.

Hoffman dismissed the charges without comment at the request of U. S. Attorney William J. Bauer. The government felt it was "inappropriate to try Seale alone on a conspiracy charge" since the seven co-defendants in the case had been acquitted on this charge, Bauer said.

Seale also faces murder conspiracy charges in New Haven, Connecticut, along with 12 other Panthers.