It had filled his mind, subconsciously, ever since he had slipped quickly in front of his brother Jack to open the front door to Mrs.Crofton, a couple of hours ago.
Mrs.Crofton was very much of a town lady, and she had actually been accompanied, during her short progress through the dark village, by her parlourmaid.

When Timmy opened the front door, she had been engaged in giving the girl a few last directions as to how a lighted candle was to be left out for her in her hall, for she had brought her latchkey with her.

After ringing the bell, the lady and her maid had moved away from the door a little way, and Timmy, staring out at the two figures, who stood illumined by the hall light out on the gravel carriage drive, had seen Something Else.
He did not invariably see Mrs.Crofton accompanied or companioned by that of which he had spoken to his mother.

Sometimes days would go by and he would see nothing, though he was a constant, if never a welcome, visitor at The Trellis House.
Then all at once, sometimes when she was in the garden, at other times in the charming little parlour, Timmy would see the wraith of Colonel Crofton, and the wraith of Colonel Crofton's terrier, Dandy, looking as real as the flesh-and-blood woman beside whom they seemed to stand.
Sometimes they appeared, as it were, intermittently, but now and again they would stay quite a long time.
As long as he could remember, Timmy had been aware of what Nanna expressed by the phrase "things that were not there," and he was so accustomed to the phenomena that it did not impress his own mind as anything very much out of the way, or strange.
Dr.O'Farrell had always shown a keen interest in Timmy's alleged visions and presentiments.

Like so many country doctors of the old school, he was a man not only of great natural shrewdness, but of considerable intellectual curiosity, and, from his point of view, by far the most inexplicable of the little boy's assertions had concerned a long vanished building which had stood, for something like three centuries, close to the parish church, right on the main street of the village.
One Easter Sunday, Timmy, coming out of church, had excitedly exclaimed that he saw to his right a house where no house had been up to yesterday.
His sisters had laughed at him and his mother had snubbed him.