Another indispensable requisite is a water-bottle--a good big one. My own belief is that a man in tolerable condition--let us say good internment-camp condition--can keep going for from two to three weeks on no more food than he can pick up in the fields. But thirty hours without water will, in most cases, be too much for him. Under the tortures of thirst his determination will be sapped. I was, therefore, always willing to exchange the most direct route for a longer one which offered good supplies of water. In my final and successful attempt, when I was leader of a party of three and had to traverse a part of Germany where brooks and streams are rare, I always preferred taking the risk of looking for fresh water rather than that of being without it for more than twenty hours between sources, relying in the meantime on what we had in our bottles. The more clothing one can take along the better--within reason, of course. One is prepared to do without a good deal, but food must, if necessary, be sacrificed for a sweater and an oilsilk. Two sets of underclothing to wear simultaneously when the weather turns cold are a comfort. Beyond this, any one will naturally take such food as can be carried conveniently. Chocolate, hardtack and dripping, with a little salt, is, in my opinion, as much as one wants. Being a deliberate person, I usually managed to have enough of these in readiness before I even thought of other arrangements for the start. People are very differently gifted with what might be called the out-of-door sense, though it is strong in some who have never really led an out-of-door life. Those who have this gift will know almost instinctively where to turn in an emergency, and will gather from the lie of the land information denied to those without it. This raises the question of companionship. As I am, fortunately, possessed of a fair share of this open-air sense, it was little handicap to me to be alone on my first attempt. In fact, as long as I was using the railways, it was a distinct advantage. At critical moments a man can decide more quickly what to do, if he has only himself to think of, than when he has to consider and possibly to communicate with a companion, who may be contemplating a better but quite different solution. To know that it is only one’s own skin that is at stake gives one that promptness of decision which is itself the seed of success; the thought of involving another man in an error easily clogs the swiftness of one’s action.