The Cleveland ironstone had been considered inferior for steelmaking, as it contained a relatively high percentage of phosphorus at 1.8 to 2.0%, weakening the resulting iron.
In 1875, Bell began to move out of working in industry by retiring from his partnership with Robert Benson Bowman and Robert Stirling Newall, leaving the two of them to continue to run the chemical works until 1878, when Newall bought out Bowman [REF].