However he exceeded his authority by committing the East India Company to guaranteeing a treaty and by confronting a possible Maratha Empire invasion.[2] He resigned in 1773: Colonel Champion, who succeeded him, had to conduct the first Rohilla war.[5]
Besides the Thermometrical Observations published by the Royal Society, Barker also contributed Observations on a Voyage from Madras to England, 1774, and The Process of Making Ice in the East Indies to volume lxv., and an Account of an Observatory of the Brahmins at Benares to volume lxvii. of the Philosophical Transactions. [5]
There is a very short, incomplete notice of Sir Robert Barker in Major Stubbs's History of the Royal Bengal Artillery, 2 volulemes, 1877
consult also Malcolm's Life of Clive, Gleig's Life of Warren Hastings, and Mill's History of India
for his services at Manila see Draper's despatch in the Gentlemen's Magazine for 1763, and for Kettle's paintings at his seat the Gentlemen's Magazine for 1786.