In 1917 Dennis and his wife set sail for England on the
Elder Dempster steamship
Karina. On 1 August they were torpedoed off the south coast of
Ireland just outside
Queenstown and the ship sank. Mattie was rescued but Dennis drowned. One of their suitcases, containing a draft of the Igbo-English dictionary and part of an Igbo grammar, later washed up on the coast of
Wales. A fisherman found it, broken open on the beach. He collected the papers and dried them out. The suitcase had Dennis's name printed on the outside, and also contained the address of a donor. The fisherman wrote to her, and she in turn contacted Mattie. By this means the dictionary manuscript was eventually returned to CMS, ==Legacy==