premise: I, Hercule Poirot, affirm that the man who entered the chemist's shop, and purchased strychnine at six o'clock on Monday last was not Mr. Inglethorp, for at six o'clock on that day Mr. Inglethorp was escorting Mrs. Raikes back to her home from a neighbouring farm. 
hypothesis: After escorting Mrs. Raikes back to her home, Mr. Inglethorp settled down to watch the game.