What to read after The Waif of the "Cynthia"?

In Noroë, Norway an exceptionally bright student is sought out by Dr. Schwaryencrona. The doctor goes to the student's home and requests that his parent's let him take their son to Norway to give him a proper education that make better use of his intellect. The parents tell the doctor of this history of this boy that came to live in their family. The father found the boy as a baby in a cradle attached to a buoy adrift at sea and the name on the buoy was Cynthia. The parents agree to let their boy Erik accompany the doctor to Stockholm for a better education, but also on the promise that the doctor will make every effort to find the boy's true parents. Erik receives a fine education but the doctor's efforts to discover his past prove unfruitful until the name Patrick O'Donoghan is discovered, he is the only sailor who survived the wreck of the Cynthia. A man named Tudor Brown keeps getting in the way of the doctor and Erik uncovering Erik's birthright as they travel on board the Alaska bound for a destination where the expect to meet the Vega the last known ship to have Patrick O'Donoghan as part of the crew.