About nine o'clock
`` Aunt Emily , '' as the children called her at once , because she was Edna May 's aunt , welcomed them as warmly as Captain May had done , and everything in the cabin of the Wildfire was so comfortable that they felt at home at once . Supper was ready as soon as they were , and as they sat down to it Mark said he wished `` Aunt Clo '' could see it , for he thought it would give her some new ideas of what Yankees had to eat . After supper each of the children wrote a letter home , and Mark and Captain May walked up to the post-office to mail them . About nine o'clock a tug came for the ship , and very soon they had bid good-bye to Savannah , and were dropping down the muddy river towards the sea . As it was a fine moonlit night , the children stayed on deck with Mrs. Coburn to see what they could of the river , which here forms the boundary line between the States of Georgia and South Carolina . On both sides , as far as they could see , the marshes were covered with fields of growing rice , and every now and then they heard the sound of music coming from the funny little negro cabins which were scattered here and there along the banks . They passed the old forts Jackson and Pulaski , both on the south side of the river , and both deserted and falling to ruin , and very soon had left behind Tybee Island , with its flashing light , at the mouth of the river .