26th.--An American brig from Portland, Captain Goodriche, master, was sold by the captain for six thousand dollars to the slave merchants. The crew then turned mutinous and refused to work after the slaves were put on board. The vessel was then manned by Spaniards, who had been put on shore from prizes taken by English men-of-war. Sending vessels nearly valueless to the coast with general cargo, and after having been visited by an English man-of-war several times, discharging their cargoes, and selling them to slave dealers, seems now to be a favourite plan with the Yankees. When the vessel sails she is not suspected, from her apparent unfitness for that trade. This vessel took on board six hundred slaves in a few hours, and though the swell was so heavy that none of the vessels in the roads could discharge their cargo, not one of the slaves was drowned. Knowing that a shipment of slaves was to take place, I stationed myself on the road where I knew they would have to pass. The first party consisted of about seventy very strong athletic men, apparently from twenty to twenty-five years of age. These were followed by a number more, carrying pails or buckets for their food on the passage. About forty were children, varying from seven to ten years of age. These were not in chains; but marched with two slight grass cords, knotted at intervals of a yard. The two cords are put, one on each side of the neck, and another knot is made in front of the neck, leaving sufficient room, but so tight as to prevent the head from being slipped through. The others were all in chains; sometimes eighty on one chain. At intervals of a yard are large circular links, which open to receive the neck, and which are secured by a padlock. I was surprised to see with what cheerfulness they all bustled along as if going to a fair. The returned or liberated slaves were all out to witness the procession, which seemed to give them great satisfaction; for they declared they had spent their happiest days in Bahia. I asked several their reason for leaving such a pleasant bondage; they assured me that it was owing to the revolt amongst some of the slaves in Bahia, who had been the means of ruining many slave-holders and large sugar manufacturers, who were unable to keep or employ them any longer. But, in all probability, these men were of the mutinous party, and had been sent out of the country.