The corollary of such a rule was perfect “intelligence,” so that we could plan in certainty. The chief agent must be the general’s head; and his understanding must be faultless, leaving no room for chance. Morale, if built on knowledge, was broken by ignorance. When we knew all about the enemy we should be comfortable. We must take more pains in the service of news than any regular staff.

I was getting through my subject. The algebraical factor had been translated into terms of Arabia, and fitted like a glove. It promised victory. The biological factor had dictated to us a development of the tactical line most in accord with the genius of our tribesmen. There remained the psychological element to build up into an apt shape. I went to Xenophon and stole, to name it, his word diathetics, which had been the art of Cyrus before he struck.