It was in Paris that my next adventure occurred. I had gone there following one of those agreeably indefinite conversations with my tutor which always preceded some especial undertaking. “Why not take a rest for a few weeks?” he would say. “You have not seen Paris in some time. You would enjoy visiting the city again—don’t you think so?” And I would obligingly agree with him—and in due course would receive whatever instructions were necessary. It may seem that such methods are needlessly cumbersome and a little too romantic to be real; but in fact there is an excellent reason for them. Work such as mine is governed too greatly by emergencies to admit of definite planning beforehand. A contingency is foreseen—faintly, and as a possibility only—and it is thought advisable to have a man on the scene. But until that contingency develops into an assured fact, it would be the sheerest waste of energy to give an agent definite instructions which might have to be changed at any moment. [Illustration: General Villa and Colonel Trinidad Rodriguez, von der Goltz’s commanding officer.] [Illustration: General Raul Madero, the brother of the murdered President of Mexico.] So I had become accustomed to receive my instructions in hints and stingy morsels, understanding perfectly that it was part of my task to discover for myself the exact details of the situation which confronted my government. If I were not sufficiently astute to perceive for myself many things which my superiors would never tell me—well, I was in the wrong profession, and the sooner I discovered it the better. I went to Paris in just that way and put up at the Grand Hotel. So far as I knew I was on genuine leave of absence from all duties and I proceeded to amuse myself. Though under no obligations to report to anyone, I did occasionally drop around to the Quai d’Orsay—where most of the embassies and consulates are—to chat with men I knew. One day it was suggested to me at the Germany Embassy that I lunch alone the next day at a certain table in the Café Americaine. “I would suggest,” said one of the secretaries, “that you wear the black derby you have on. It is quite becoming,”—this with an expressionless face. “I would suggest also that you hang it on the wall behind your table, not checking it. Take note of the precise hook upon which you hang it. It may be that there will be a man at the next table who also will be wearing a black derby hat, which he will hang on the hook next to yours. When you go out be careful to take down his hat instead of your own.” I asked no questions. I knew better. Old and well known as it is, the “hat trick” is perennially useful. Its very simplicity makes it difficult of detection. It is still the best means of publicly exchanging documents between persons who must not be seen to have any connection with each other.