The Trial of Capt. John Lockhart, for misdemeanor, (in being a passenger on board a vessel engaged in the slave trade,) was commenced before Judge Halyburton yesterday, in the U. S. District Court. His counsel objected to the first count in the indictment, which was decided by the Judge to be of no account, and the instrument was quashed.--A grand jury was ordered to convene at 5 o'clock to make another presentment, --Prisoner was offered bail, if he chose to avail himself of it.