in the spring of 1768 he resigned his commission, being disappointed at not meeting with more sympathy in his studies from his brother-officers. he found, however, one congenial friend in alexander blair, afterwards a captain in the 69th regiment of foot. while in the army keir wrote a treatise on the art of war, which was accidentally burnt at his publishers, and a pamphlet addressed to the marquis of granby in favour of the sale of commissions. at this same period he used to rise at four o'clock in the morning to read the classics and military writers, and he translated many chapters of polybius.