When Mahbub Ali gives Kim his first special message to bring to the Englishman in the city of Umballa, that Englishman turns out to be Colonel Creighton. Creighton is working for the "Ethnological Survey" (6.116), which is totally code for spy stuff. "Ethnology" means the study of different races and peoples—their manners, their customs, that kind of thing. Creighton's interest in "ethnology" is very specific: he wants to keep an eye on the peoples of India, using his vast spy network to nip any kind of rebellion against British authority in the bud.
The fact that Creighton is both an ethnologist—a student of people's manners and customs—and a military guy really reaffirms one of the major messages of this book: that there is a close connection between knowing about people and maintaining control over them. Creighton insists that Kim continue to learn and remain open-minded about the people around him, since people in Government service who refuse to try to understand "the talk or the customs of black men" (7.41) get their pay cut.
Creighton's insistence on the importance of learning local customs may seem super-liberal as an attitude from an army officer toward the people his country has conquered, but it's a little creepy that Creighton insists on studying the manners and habits of the Indian people at the same time that he is thinking up military strategies to keep India a colony of Britain.
Creighton's supposedly academic analysis of "strange Asiatic cults and unknown customs" (10.51) is not at all neutral or removed from the real world. The men of the Great Game apply this kind of anthropological information to their spying activities all the time in this book.
Consider Kim's disguise of Agent E.23 as a Saddhu holy man, or the Babu's use of the Sat Bhai secret society as a cover story for his silver amulets (which we discuss in the section "Symbols, Imagery, Allegory"). These agents are always adapting information about the manners and habits of the peoples of India in order to watch those people all the more closely and effectively.
Creighton's desire to join the academic ranks of the "silver-haired, bald-headed gentlemen who knew nothing of the Army" (10.51) at the Royal Society back in London cannot hide the fact that the information-gathering he does now has huge real-world consequences for the people he is keeping under such close watch.
Of course, it is precisely this link between the social sciences (geography, anthropology, and what have you) and the military that so attracts Kim to Creighton. When Kim first sees Creighton reading over Mahbub Ali's message about the five rebellious northern kings, Creighton takes immediate steps to arrange for the army to march north and teach these kings a lesson. Kim is impressed by this big news involving eight thousand troops and a real, live war. Creighton's combination of information-gathering (from agents such as Mahbub Ali and Kim himself), quick decision-making, and military authority is deeply appealing to Kim.