 Delprat was born in Delft, the Netherlands, son of Major General Felix Albert Theodore Delprat (1812–1888), later minister of war, and his wife Elisabeth Francina, "née" van Santen Kolff.Delprat attended a high school in Amsterdam and later became an apprentice engineer on the Tay Bridge in Scotland.He attended science classes in Newport-on-Tay and learned calculus from his father by post.