He became associated with James Watt when Watt 's business partner , John Roebuck , was unable to pay a debt to Boulton , who accepted Roebuck 's share of Watt 's patent as settlement .
When Watt 's business partner , John Roebuck was unable to pay a debt to Boulton , he accepted Roebuck 's share of Watt 's patent as settlement .