The high and loyal principles which actuate all our … officers would, I am fully persuaded, prevent any wilful deviation from the instructions laid down by competent authority. But where theories are strongly held, they often insensibly influence the course of action, and lead unconsciously to interpretations and inferences in accordance with these theories.

I was thus in a good position for finding out by practice the mode of putting a thought which gives it easiest admittance into minds not prepared for it by habit; while I became practically conversant with the difficulties of moving bodies of men, the necessities of compromise, the art of sacrificing the non-essential to preserve the essential. I learnt how to obtain the best I could, when I could not obtain everything … to be pleased and encouraged when I could have the smallest part of it.