In 1887 Douglass was elected a Fellow of the Royal Society. He retired in 1892, being succeeded as Engineer-in-Chief by Thomas Matthews, and died in 1898 at his home on the Isle of Wight.
Douglass's election to the Royal Society in 1887 marked an important milestone. He left his role as Chief Engineer in 1892, which was taken over by Thomas Matthews, and passed away in 1898 at his home on the Isle of Wight.