In 1804, at the age of twenty-two, having completed his apprenticeship, and in the middle of the Napoleonic Wars, Jonathan became “intent on travelling to foreign countries”. He travelled to London where he was deceived into boarding a ship called the ‘Enterprise’, to find himself press-ganged as an ordinary seaman in the Royal Navy. He was taken aboard the ‘Hercules’, a seventy-four gun battleship, destined for Copenhagen. He “felt deeply concerned for (his) soul, convinced that (he) was not ready to die.” He “got safe home, however, with such a prize as England never saw before.” Many other dangerous adventures followed throughout Spain and Portugal, including taking part in the famous evacuation of the British Army from Corruna during Sir John Moore’s retreat, and surviving falling overboard on four separate occasions. He immediately followed his service in the Royal Navy with a spell in the Merchant Navy, completing a total period of six consecutive years at sea.