about two o'clock
The chapter on `` Ars Bibliopolae , '' or the art of bookselling , would be , he hoped , a classic among generations of book vendors still unborn . Seated at his disorderly desk , caressed by a counterpane of drifting tobacco haze , he would pore over the manuscript , crossing out , interpolating , re-arguing , and then referring to volumes on his shelves . Bock would snore under the chair , and soon Roger 's brain would begin to waver . In the end he would fall asleep over his papers , wake with a cramp about two o'clock , and creak irritably to a lonely bed . All this we mention only to explain how it was that Roger was dozing at his desk about midnight , the evening after the call paid by Aubrey Gilbert . He was awakened by a draught of chill air passing like a mountain brook over his bald pate . Stiffly he sat up and looked about .