Complex sentence: To resolve this, the Admiralty instructed Captain Robert FitzRoy to command on a survey expedition which included as one of its essential requirements a stop at Fernando Noronha to confirm its exact longitude using the 22 chronometers on board the ship to give the precise time of observations.
Split into simpler sentences: To resolve this, the Admiralty instructed Captain Robert FitzRoy to command on a survey expedition. One of its essential tasks was a stop at Fernando Noronha to confirm its exact longitude, using the 22 chronometers on board the ship to give the precise time of observations.