Final answer:
The tavern keeper who tries to save Isabel and Ruth is Mr. Ruggles.
Step-by-step explanation:
The tavern keeper who tries to save Isabel and Ruth by purchasing them in Newport instead of the Locktons is Mr. Ruggles. Upon receiving a certificate and a five-dollar bill from Mr. Ruggles, Isabel and Ruth set out to take passage on board the steamboat John W. Richmond for Newport, on their way to New Bedford. Mr. Ruggles gave them a letter to a Mr. Shaw in Newport, and although they lacked the necessary money to pay their fare, they decided to take seats in the stage and promised to pay when they got to New Bedford.