John Buchan 
The Island of Sheep 

I have never believed, as some people do, in I omens and forewarnings, for the dramatic things in my life have generally come upon me as suddenly as a tropical thunderstorm. But I have observed that in a queer way I have been sometimes prepared for them by my mind drifting into an unexpected mood. I would remember something I had not thought of for years, or start without reason an unusual line of thought. That was what happened to me on an October evening when I got into the train at Victoria.