He gave up the legal profession, for which he was destined, and in 1740 went to Paris, where he studied natural history, chemistry, and metallurgy.
He subsequently traveled through France, investigating its natural history and mineral and other productions. In 1752, having become acquainted with Don Antonio de Ulloa, afterwards admiral of the Spanish fleet, Bowles was induced to enter the Spanish service, being appointed to superintend the state mines and to form a collection of natural history and fit up a chemical laboratory. He first visited the mercury mines of Almadén, which had been seriously damaged by fire, and the plans he suggested were successfully adopted for their resuscitation.
He afterwards traveled through Spain, investigating its minerals and natural history, living chiefly at Madrid and Bilbao.
Bowles is described as tall and fine-looking, generous, honourable, active, ingenious, and well informed. His society was much valued in the best Spanish circles.
He died at Madrid on 25 August 1780.