Longitude
John Harrison
Rupert Gould
Elizabeth Harrison
Muriel Gould
Sir Kenhelm Digby
Laura Gurney
Dodo Gould
John Jefferies
Commodore Forrest
Christopher Irwin
Capt. Man
Halley's Secretary (uncredited)
Admiral Wagner
Admiral Balchen
Sir Frank Dyson
John Campbell
Captain Proctor
Edmund Halley
George Graham
Lieutenant (uncredited)