THE PHILADELPHIA SLAVE CASE.-A correspondent in Philadelphia, in a letter dated Aug. 9, says:-
'The Grand Jury found true bills yesterday against Passmore Williamson and the five colored men for riot and assault and battery; also against William Still, another colored man, clerk in the Anti-Slavery office. Mr. Still, on hearing of his indictment, went forward voluntarily, and entered bonds for his appearance. J. M. McKim, Secretary of the Anti-Slavery Society, became his security.
The case came on to-day for trial; but the defendants not having been able, on so short a notice, to prepare their testimony, asked for a continuance, which after a good deal of resistance on the part of the counsel for Mr. Wheeler, was granted. The case is postponed till the 27th instant.’