ondered in what the lodger's experiments
consisted. It was odd that she had never been able to discover what
it was he really did with that big gas-stove. All she knew was
that he used a very high degree of heat.

CHAPTER XV

The Buntings went to bed early that night. But Mrs. Bunting made
up her mind to keep awake. She was set upon knowing at what hour
of the night the lodger would come down into her kitchen to carry
through his experiment, and, above all, she was anxious to know
how long he would stay there.

But she had had a long and a very anxious day, and presently she
fell asleep.

The church clock hard by struck two, and, suddenly Mrs. Bunting
awoke. She felt put out, sharply annoyed with herself. How could
she have dropped off like that? Mr. Sleuth must have been down
and up again hours ago!

Then, gradually, she became aware that there was a faint acrid
odour in the room. Elusive, intangible, it yet seemed to encompass
her and the snoring man by her side, almost as a vapour might have
done.

Mrs. Bunting sat up in bed and sniffed; and then, in spite of the
cold, she quietly crept out of her nice, warm bedclothes, and
crawled along to the bottom of the bed. When there, Mr. Sleuth's
landlady did a very curious thing; she leaned over the brass rail
and put her face close to the hinge of the door giving into the
hall. Yes, it was from here that this strange, horrible odor was
coming; the smell must be very strong in the passage.

As, shivering, she crept back under the bedclothes, she longed to
give her sleeping husband a good shake, and in fancy she heard
herself saying, "Bunting, get up! There's something strange and
dreadful going on downstairs which we ought to know about."

But as she lay there, by her husband's side, listening with painful
intentness for the slightest sound, she knew very well that she
would do nothing of the sort.

What if the lodger did make a certain amount of mess--a certain
amount of smell--in her nice clean kitchen? Was he not--was he
not an almost perfect lodger? If they did anything to upset him,
where could they ever hope to get another like him?

Three o'clock struck before Mrs. Bunting heard slow, heavy steps
creaking up the kitchen stairs. But Mr. Sleuth did not go straight
up to his own quarters, as she had expected him to do. Instead, he
went to the front door, and, opening it, put on the chain. Then he
came past her door, and she thought--but could not be su